Domestic Terrorism: Overview of Federal Criminal Law and Constitutional Issues

Domestic Terrorism: Overview of Federal Criminal Law and Constitutional Issues

Domestic Terrorism: Overview of Federal
July 2, 2021
Criminal Law and Constitutional Issues
Peter G. Berris
Federal statute defines domestic terrorism to include dangerous criminal acts intended to
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intimidate or coerce a civilian population or to influence or affect government policy or conduct

within the jurisdiction of the United States. Despite the federal statutory definition, no federal
Michael A. Foster
criminal provision expressly prohibits “domestic terrorism.” Nevertheless, numerous federal
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statutes offer prosecutors options in charging violent and destructive conduct consistent with the

statutory definition of domestic terrorism. Some of these statutes can be characterized as
expressly focused on terrorism, listing criminal offenses to include, among others, providing
Jonathan M. Gaffney
material support or resources to terrorists and engaging in terrorism transcending domestic
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boundaries. Other generally applicable federal criminal laws may also be relevant to domestic

terrorism prosecutions. For example, depending on the defendant’s motive, target, or means,
various federal criminal statutes protecting certain property or persons, prohibiting violence

motivated by particular biases, or criminalizing possession or use of specific weapons may apply.
Depending on the circumstances, prosecutors may also rely on accomplice liability or inchoate offenses such as attempt,
conspiracy, or solicitation to charge conduct consistent with the definition of domestic terrorism. Beyond applicable offenses,
domestic terrorism may be relevant in federal sentencing, either through specific statutes that authorize additional penalties in
the domestic terrorism context or through the United States Sentencing Guidelines, which include an upward adjustment for
offenses connected to terrorism.
Civil disturbances over the past year have reportedly heightened interest in laws governing domestic terrorism, a topic that
has long been a matter of congressional concern. As a number of proposals introduced in the 116th and 117th Congresses
reflect, Congress remains interested in additional legislation addressing domestic terrorism, and any legislative action in this
area would take place against the backdrop of a broader discussion of potential policy concerns and constitutional
considerations. For instance, some observers dispute whether there is a gap in the existing federal domestic terrorism legal
regime that leaves some violent or destructive conduct outside the scope of federal jurisdiction, and, if so, what new criminal
provisions would be required. Additionally, certain constitutional constraints, such as First Amendment protections, Fourth
Amendment restrictions on government searches, and broader federalism-based limitations on federal jurisdiction, may be
relevant should Congress consider new domestic terrorism law.

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Contents
Introduction ..................................................................................................................................... 1
Federal Criminal Terrorism Laws .................................................................................................... 2
Material Support: 18 U.S.C. §§ 2339A & 2339B ..................................................................... 3
Material Support to Terrorists Under 18 U.S.C. § 2339A ................................................... 3
Material Support to Foreign Terrorist Organizations Under 18 U.S.C. § 2339B ................ 7
Terrorism Transcending National Boundaries: 18 U.S.C. § 2332b ........................................... 9
Remaining Chapter 113B Offenses .......................................................................................... 11
Other Federal Criminal Laws Applicable to Domestic Terrorism ................................................. 14
Substantive Criminal Laws ..................................................................................................... 14
Crimes of Violent Unrest .................................................................................................. 16
Crimes against Government Authority ............................................................................. 19
Crimes against Persons ..................................................................................................... 22
Crimes Involving Infrastructure or Federal Property ........................................................ 26
Hate Crimes ...................................................................................................................... 28
Crimes Involving Specific Weapons ................................................................................. 32
Crimes Involving Threats.................................................................................................. 37
Crimes Involving Computers ............................................................................................ 39
Inchoate and Accomplice Liability ......................................................................................... 41
Conspiracy ........................................................................................................................ 42
Attempt ............................................................................................................................. 42
Solicitation ........................................................................................................................ 43
Accomplice Liability ........................................................................................................ 44
Domestic Terrorism at Sentencing ................................................................................................ 45
Statutes with Terrorism-Related Sentence Enhancement Provisions ...................................... 45
Terrorism under the U.S. Sentencing Guidelines .................................................................... 47
Considerations for Congress.......................................................................................................... 49
Is there a Gap in Current Law? ............................................................................................... 49
Differences in Offenses and Sentences ............................................................................. 49
Differences in Intelligence Gathering ............................................................................... 51
Need for a Separate Domestic Terrorism Law .................................................................. 53
Constitutional Issues ............................................................................................................... 54
Federalism ......................................................................................................................... 54
The First Amendment ....................................................................................................... 55
Fourth Amendment ........................................................................................................... 60
Legislative Proposals .............................................................................................................. 62
117th Congress .................................................................................................................. 62
116th Congress .................................................................................................................. 63

Tables
Table 1. Comparison of Domestic Terrorism Legislation .............................................................. 66

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Contacts
Author Information ........................................................................................................................ 67

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Introduction
Domestic terrorism has been an issue of longstanding congressional concern.1 Occurrences such
as the events of January 6, 2021, at the U.S. Capitol—which involved some conduct that federal
law enforcement described as domestic terrorism2—have reportedly heightened congressional
interest in the federal statutory regime governing domestic terrorism.3
Federal statute defines domestic terrorism as:
[A]ctivities that--
(A) involve acts dangerous to human life that are a violation of the criminal laws of
the United States or of any State;
(B) appear to be intended--
(i) to intimidate or coerce a civilian population;
(ii) to influence the policy of a government by intimidation or coercion; or
(iii) to affect the conduct of a government by mass destruction, assassination, or
kidnapping; and
(C) occur primarily within the territorial jurisdiction of the United States.[4]
Although defined in federal law, there is no federal criminal provision expressly prohibiting
“domestic terrorism,” as the terms defining domestic terrorism are not elements of criminal
offenses.5 Conduct consistent with the definition of domestic terrorism may still be a federal

1 See, e.g., Domestic Terrorism Prevention Act of 2017, S. 2148, 115th Cong. (2017); Establishing the Select
Committee on White Supremacy and Domestic Terror Movements, H.R. 515, 115th Cong. (2017); Animal Enterprise
Terrorism Act, P.L. 109-374, 120 Stat. 2652 (2006); Antiterrorism Act of 1993, H.R. 1438, 103rd Cong. (1993);
Terrorism Prevention and Protection Act of 1993, H.R. 1301, 103rd Cong. (1993); see also infra, § “Legislative
Proposals.”
2 See, e.g., FBI Oversight/Current Security Threats: Hearing Before the Senate Judiciary Committee, 117th Cong.
(Mar. 2, 2021) (statement of Christopher Wray, Dir., FBI) [hereinafter FBI Oversight Hearing] (describing some
conduct committed during the events of January 6 as domestic terrorism).
3 See, e.g., Greg Myre, An Old Debate Renewed: Does The U.S. Now Need A Domestic Terrorism Law?, NPR (Mar.
16, 2021), https://www.npr.org/2021/03/16/976430540/an-old-debate-renewed-does-the-u-s-now-need-a-domestic-
terrorism-law; Karoun Demirjian, Bipartisan Support Emerges for Domestic-Terror Bills as Experts Warn Threat May
Last ‘10 to 20 Years’, WASH. POST (Feb. 4, 2021), https://www.washingtonpost.com/national-security/capitol-riot-
domestic-terror-legislation/2021/02/04/f43ec214-6733-11eb-8468-21bc48f07fe5_story.html; Raquel Martin, Renewed
Push in Congress to Pass Bill Targeting Domestic Terrorism, ABC NEWS (Jan. 27, 2021),
https://www.abc27.com/news/renewed-push-in-congress-to-pass-bill-targeting-domestic-terrorism/. Such events have
also prompted additional focus on domestic terrorism by the Executive Branch. See Attorney General Merrick B.
Garland, Remarks: Domestic Terrorism Policy Address (June 30, 2021), https://www.justice.gov/opa/speech/attorney-
general-merrick-b-garland-remarks-domestic-terrorism-policy-address (describing DOJ strategy for countering
domestic terrorism as an “effort” that “comes on the heels of another large and heinous attack – this time, the January
6th assault on our nation’s Capitol”); see generally U.S. DEP’T OF JUSTICE, NATIONAL STRATEGY FOR COUNTERING
DOMESTIC TERRORISM (June 2021).
4 18 U.S.C. § 2331(5). Unless noted otherwise, the term “domestic terrorism” as used in this report refers to conduct
consistent with this definition. Law enforcement also use a number of other terms in contexts similar to domestic
terrorism, such as “homegrown violent extremism.” Additional clarification on such terminology may be found in
another CRS product. See generally CRS Insight IN10299, Sifting Domestic Terrorism from Hate Crime and
Homegrown Violent Extremism, by Lisa N. Sacco. Various state laws may also prohibit domestic terrorism but are
beyond the scope of this report. See Shirin Sinnar, Separate and Unequal: The Law of "Domestic" and "International"
Terrorism, 117 MICH. L. REV. 1333, 1353-54 (2019).
5 CRS Legal Sidebar LSB10340, Domestic Terrorism: Some Considerations, by Charles Doyle.
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crime, however, under numerous statutes prohibiting terrorism6 and other types of violent or
destructive conduct.7 In addition, domestic terrorism may be relevant to the sentencing of those
convicted of federal crimes.8
Any congressional consideration of additional legislation in the area of domestic terrorism—such
as a criminal statute expressly prohibiting acts of domestic terror—would necessarily involve a
broader discussion of potential policy concerns and constitutional constraints.9 For example,
some observers have debated whether a gap exists in federal criminal law leaving certain acts of
domestic terrorism beyond the scope of federal jurisdiction.10 Legislation seeking to address
domestic terrorism also may implicate certain constitutional considerations, such as First
Amendment protections of speech and association, Fourth Amendment restrictions on
government searches, and broader federalism-based restraints on federal jurisdiction in general.11
This report provides an overview of federal criminal terrorism laws and analyzes the extent to
which they might apply in the context of domestic terrorism. It next summarizes other generally-
applicable substantive criminal laws, including inchoate offenses such as conspiracy, which might
impose criminal liability for acts considered domestic terrorism. This report then briefly describes
how domestic terrorism could potentially impact federal sentencing outcomes. Next, the report
discusses various considerations in enacting new domestic terrorism legislation, including the
extent to which there may be a gap in federal laws applicable to domestic terrorism, as well as
relevant constitutional limitations on additional legislation. It concludes with an overview of
select legislative proposals introduced in the 116th and 117th Congresses.
Federal Criminal Terrorism Laws
Chapter 113B of Title 18 of the U.S. Code identifies certain federal criminal offenses under the
heading of “terrorism.”12 Some of the provisions in Chapter 113B expressly relate to international
conduct or “foreign” terrorist organizations, but many others can apply to conduct with either an
international or domestic focus.13 Two of the principal criminal provisions in Chapter 113B

6 Infra, § “Federal Criminal Terrorism Laws.”
7 Infra, § “Substantive Criminal Laws.”
8 Infra, § “Domestic Terrorism at Sentencing.”
9 Infra, § “Considerations for Congress.”
10 Infra, § “Is there a Gap in Current Law?”
11 Infra, § “Constitutional Issues.”
12 As described infra, one of the offenses in Chapter 113B incorporates a larger list of federal crimes, many from other
chapters, which are defined separately as “federal crimes of terrorism” if certain additional requirements are met. A
federal crime of terrorism is defined as a listed offense that is “calculated to influence or affect the conduct of
government by intimidation or coercion, or to retaliate against government conduct.” 18 U.S.C. § 2332b(g)(5)(B); see
id. § 2339A(a) (proscribing material support in connection with listed offenses, among other things). For instance, one
offense found outside of Chapter 113B and included as a federal crime of terrorism concerns attacks on mass
transportation systems. See id. § 2332b(g)(5)(B); id. § 1992. Many other federal criminal statutes also may be used to
prosecute conduct meeting the definition of “domestic terrorism” in 18 U.S.C. § 2331(5) or the definition of
“terrorism” in 28 C.F.R. § 0.85(l) (“Terrorism includes the unlawful use of force and violence against persons or
property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of
political or social objectives.”). A number of the statutes found outside Chapter 113B are addressed infra, § “Other
Federal Criminal Laws Applicable to Domestic Terrorism.” Inclusion on the list of federal crimes of terrorism has other
legal implications and effects, such as constituting predicate offenses for other federal crimes like RICO violations, 18
U.S.C. § 1961(1), and extending the applicable statute of limitations. See id. § 3286.
13 E.g., 18 U.S.C. § 2332a (proscribing use of weapons of mass destruction); id. § 2339A (proscribing providing
material support or resources in furtherance of certain federal crimes).
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Domestic Terrorism: Overview of Federal Criminal Law and Constitutional Issues

prohibit “material support,” which is either (1) knowing that such support will be used or
intending that such support be used to commit violations of separate federal criminal statutes
associated with terrorism14 or (2) where such support is of a designated foreign terrorist
organization.15 Additional offenses in Chapter 113B address “acts of terrorism transcending
national boundaries”16 and specific terrorism-related activities such as, among other things,
possessing or using certain kinds of weapons17 or engaging in financial transactions with
governments of countries that support international terrorism.18 This section provides an overview
of the criminal offenses19 in Chapter 113B, focusing on the provisions that proscribe material
support of terrorism and terrorism transcending national boundaries.
Material Support: 18 U.S.C. §§ 2339A & 2339B
Some of the most common20 federal charges in terrorism cases are the so-called “material
support” offenses found in Sections 2339A and 2339B of Title 18 of the U.S. Code. Though both
provisions use the term “material support or resources,” they have substantially different
requirements in terms of the objects of such support and the mental state required to commit the
crime, among other things. Broadly, Section 2339A prohibits providing support for specific
terrorism-related criminal offenses, while Section 2339B prohibits providing support to foreign
terrorist organizations. As such, Section 2339A can apply to conduct meeting the definition of
domestic terrorism, depending on the applicable offense being supported, while Section 2339B
may be viewed as being limited in scope to international terrorism.21 This report addresses both
provisions for purposes of comparison.
Material Support to Terrorists Under 18 U.S.C. § 2339A
18 U.S.C. § 2339A prohibits (1) providing “material support or resources”; (2) concealing or
disguising “the nature, location, source, or ownership of material support or resources”; or
(3) attempting or conspiring to so provide, conceal, or disguise material support or resources;
while knowing or intending that the material support or resources will be used to prepare for or
carry out a violation of at least one of over fifty predicate federal offenses or to prepare for or
carry out the concealment of escape from such a violation.22 The statute defines “material support
or resources” broadly as tangible or intangible property, services, or personnel (including the

14 Id. § 2339A.
15 Id. § 2339B.
16 Id. § 2332b.
17 E.g., id. § 2332h.
18 Id. § 2332d.
19 Several sections of Chapter 113B address matters such as, among other things, civil remedies for victims of
international terrorism, id. § 2333, and requests for military assistance during emergency situations involving weapons
of mass destruction, id. § 2332e. These and other non-criminal legal matters related to terrorism are beyond the scope
of this report.
20 See HUMAN RIGHTS WATCH, ILLUSION OF JUSTICE: HUMAN RIGHTS ABUSES IN U.S. TERRORISM PROSECUTIONS 62-63
& n. 247 (2014), https://www.hrw.org/report/2014/07/21/illusion-justice/human-rights-abuses-us-terrorism-
prosecutions (concluding that material support charges constituted largest share of convictions in terrorism cases since
September 11, 2001).
21 See MICHAEL GERMAN & SARA ROBINSON, BRENNAN CTR. FOR JUST., WRONG PRIORITIES ON FIGHTING TERRORISM 8
(2018), https://www.brennancenter.org/sites/default/files/2019-08/Report_Wrong_Priorities_Terrorism.pdf (describing
“limited application of § 2339B to international terrorism cases”).
22 18 U.S.C. § 2339A(a).
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person providing the support)23 and gives an inclusive list of examples such as currency,
monetary instruments, financial securities, financial services, lodging, training,24 expert advice or
assistance,25 safehouses, false documentation or identification, communications equipment,
facilities, weapons, lethal substances, explosives, and transportation.26 In short, Section 2339A
prohibits supporting in various ways the preparation for, commission of, or concealment of
escape from commission of other, specifically listed terrorism-related offenses.
As noted, the material support or resources must relate to a separate federal offense listed in the
statute.27 According to one scholar,28 the predicate offenses in Section 2339A generally can be
separated into three categories: (1) offenses “committed with particular weapons” (like explosives
or nuclear weapons)29 or “tactics historically associated with terrorism” (such as hostage
taking30); (2) offenses where there is a “distinct federal interest” in the target of violence (e.g.,

23 18 U.S.C. § 2339B, which prohibits providing material support or resources to designated foreign terrorist
organizations, contains a more specific definition of “personnel,” but at least one court has held that that definition does
not apply to Section 2339A and that providing personnel under Section 2339A includes making available or furnishing
individuals (including oneself) “for the purpose of actively preparing for or carrying out the crimes prohibited by the
statute through some form of coordinated action.” United States v. Abu-Jihaad, 600 F. Supp. 2d 362, 400 (D. Conn.
2009); see also Estate of Parsons v. Palestinian Auth., 952 F. Supp. 2d 61, 68 (D.D.C. 2013) (finding Abu-Jihaad
definition of “personnel” to be “compelling” and applying it in civil action).
24 “Training” is separately defined as “instruction or teaching designed to impart a specific skill, as opposed to general
knowledge.” Id. § 2339A(b)(2). These and other definitions related to specific kinds of material support appear to have
been enacted to address certain constitutional concerns, which are discussed in more detail infra, § “Constitutional
Issues.” See also, e.g., Holder v. Humanitarian L. Project, 561 U.S. 1, 21 (2010) (noting “narrowing definitions” added
to Section 2339A in upholding Section 2339B against constitutional challenge); United States v. Amawi, 695 F.3d 457,
482 (6th Cir. 2012) (“[A]lthough the conspiracy was closely related to, and indeed proved by, many of the defendants’
conversations about political and religious matters, the conviction was based on an agreement to cooperate in the
commission [of] a crime, not simply to talk about it.”); United States v. Stewart, 590 F.3d 93, 115 (2d Cir. 2009)
(acknowledging lack of dispute “that section 2339A may not be used to prosecute mere advocacy or other protected
speech” under First Amendment but recognizing that speech integral to criminal conduct is unprotected).
25 “Expert advice or assistance” is separately defined as “advice or assistance derived from scientific, technical or other
specialized knowledge.” Id. § 2339A(b)(3).
26 Id. § 2339A(b)(1). Medicine and religious materials are excepted from the definition. Id. More broadly, providing
material support or resources is distinct from accomplice liability for a federal offense under 18 U.S.C. § 2. That
provision establishes liability for anyone who “aids, abets, counsels, commands, induces or procures” the commission
of a federal crime. Id. § 2(a). However, one court has noted that “proving that a person provided ‘material support’
requires more than merely encouraging or counseling someone to commit a crime,” which is all that is required for
liability under Section 2. United States v. Abu Khatallah, 151 F. Supp. 3d 116, 142 (D.D.C. 2015). Accomplice liability
is discussed more generally infra, § “Accomplice Liability.”
27 18 U.S.C. § 2339A(a). Almost all of the separate offenses listed in Section 2339A(a) are also included in the list of
“federal crimes of terrorism” in Section 2332b(g)(5)(B), which is itself mostly incorporated for purposes of Section
2339A, though there are a few differences—for example, 18 U.S.C. § 1091, addressing genocide, is included as a
predicate offense in Section 2339A but is not listed as a federal crime of terrorism under 2332b(g)(5)(B). Section
2339A, and the other material support provision in Section 2339B, are also included in the list of “federal crimes of
terrorism” in Section 2332b(g)(5)(B) but are excepted from incorporation as predicate offenses for purposes of material
support under Section 2339A, presumably to prevent the apparent redundancy of providing material support or
resources for providing material support or resources. See id. § 2339A(a).
28 Sinnar, supra note 4.
29 E.g., 18 U.S.C. § 844(i) (proscribing malicious destruction of or damage to certain property “by means of fire or an
explosive”); id. § 2332i (addressing acts of nuclear terrorism).
30 See id. § 1203.
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killing a federal employee31 or attacking communication lines or systems32); and (3) offenses
“with an international nexus” (such as conspiring to murder, kidnap, or maim persons abroad33).
At least two commentators have examined the Section 2339A predicate offenses individually and
concluded that the vast majority—fifty-one, to be precise—can apply to domestic terrorism.34 For
instance, in 2018, a Florida resident mailed explosive devices to a number of government officials
and public figures, ostensibly motivated by domestic political views.35 Among many other things,
he was charged with multiple counts of using a weapon of mass destruction in violation of 18
U.S.C. § 2332a,36 which is a predicate offense listed in Section 2339A. Both the federal
prosecutors and the judge in the case referred to the man’s actions as “domestic terrorism.”37
Thus, assuming the predicate offense for a Section 2339A charge is one that does not require an
international nexus or conduct—like Section 2332a in the preceding example—“material
support” under Section 2339A can include purely domestic conduct and/or U.S.-based
ideologically motivated conduct.38
One who provides material support or resources under Section 2339A must, in order to violate the
statute, do so “knowing or intending that they are to be used” in connection with one of the listed
predicate offenses.39 This mens rea, or mental-state, requirement “extends both to the support
itself, and to the underlying purposes for which the support is given.”40 In other words, the statute

31 Id. § 1114.
32 Id. § 1362.
33 Id. § 956(a)(1).
34 GERMAN & ROBINSON, supra note 21, at 5-6; AMY C. COLLINS, GEO. WASH. UNIV. PROGRAM ON EXTREMISM, THE
NEED FOR A SPECIFIC LAW AGAINST DOMESTIC TERRORISM 12 (2020),
https://extremism.gwu.edu/sites/g/files/zaxdzs2191/f/The%20Need%20for%20a%20Specific%20Law%20Against%20
Domestic%20Terrorism.pdf.
35 See Katie Honan, Scott Calvert & Arian Campo-Flores, Suspect in Letter Bombs: A History of Arrests and a Prior
Bomb Threat, WALL ST. J. (Oct. 26, 2018), https://www.wsj.com/articles/suspect-in-letter-bombs-a-history-of-arrests-
and-a-prior-bomb-threat-1540572060.
36 See United States v. Sayoc, No. 18-CR-820, 2019 WL 1452501, at *1 (S.D.N.Y. Mar. 28, 2019) (verdict).
37 See United States v. Sayoc, 388 F. Supp. 3d 300, 302 (S.D.N.Y. 2019) (imposing sentence); Press Release, Dep’t of
Justice, Cesar Sayoc Pleads Guilty to 65 Felonies for Mailing 16 Improvised Explosive Devices in Connection with
October 2018 Domestic Terrorist Attack (Mar. 21, 2019), https://www.justice.gov/opa/pr/cesar-sayoc-pleads-guilty-65-
felonies-mailing-16-improvised-explosive-devices-connection.
38 E.g., United States v. Looker, 168 F.3d 484 (4th Cir. 1998) (table op.) (involving commander of militia organization
in West Virginia who discussed targets of violence in contemplated conflict between militia and federal government
and ordered the manufacture of improvised explosive devices for sale to undercover FBI agent posing as broker for
resale to terrorist organizations). As described supra, the definition of “domestic terrorism” in the U.S. Code requires
that the conduct occur “primarily within the territorial jurisdiction of the United States” but does not speak to the
source of the object or ideology. 18 U.S.C. § 2331(5). Thus, theoretically, even acts perpetrated in service of a foreign-
influenced ideology or transnational goals could fall within the statutory definition of “domestic terrorism.” See, e.g.,
Smith ex rel. Smith v. Islamic Emirate of Afghanistan, 262 F. Supp. 2d 217, 221 (S.D.N.Y. 2003) (“The acts of
September 11 clearly ‘occurred primarily’ in the United States—indeed, they occurred entirely in the United States:
airplanes owned and operated by U.S. carriers took off from U.S. airports and were in route to U.S. destinations when
they were hijacked and crashed into U.S. landmarks.”). However, the FBI apparently views domestic terrorism as
suggesting “ideological goals stemming from domestic influences, such as racial bias and anti-government sentiment.”
CRS Insight IN11573, Domestic Terrorism and the Attack on the U.S. Capitol, by Lisa N. Sacco. In any event,
although Section 2339A was “designed to punish activity connected to terrorism, an association with terrorism is not an
element of the crime” itself. United States v. Abu Khatallah, 151 F. Supp. 3d 116, 139 (D.D.C. 2015). Thus, “criminal
liability under § 2339A attaches regardless of any linkage to terrorism,” either domestic or international. Id.
39 18 U.S.C. § 2339A(a).
40 United States v. Mehanna, 735 F.3d 32, 43 (1st Cir. 2013).
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imposes “an explicit specific intent requirement to further illegal activities,”41 meaning that the
defendant must have intended, or at least known, not just that he or she was providing material
support or resources but that the material support or resources would be used to facilitate a
violation of one of the predicate offenses.42
In addition to the actual provision of material support or resources under Section 2339A, the
statute proscribes attempts and conspiracies to do the same.43 These crimes are “inchoate,”
meaning that they are “crimes on their way to becoming other crimes unless stopped or
abandoned.”44 An attempt to violate Section 2339A requires (1) “intent to commit the object
crime”45 (i.e., providing material support or resources with the requisite mental state) and (2) “at
least one substantial step toward the actual commission” of the crime.46 So long as these elements
are present, it is no defense to liability that completion of the crime would have been factually
impossible—for instance, if the attempt was to provide material support or resources to what
turned out to be undercover law enforcement officers.47
With respect to conspiracy, its “essence” is an agreement to commit an act in violation of the
law.48 Conspiracies to commit federal crimes are proscribed under 18 U.S.C. § 371, which
additionally requires that at least one of the conspirators commits an “overt act” to further the
conspiracy.49 However, the conspiracy provision of Section 2339A does not carry an overt-act
requirement, meaning that agreement to provide material support or resources with the requisite
mental state is sufficient for liability.50 Some of the offenses listed in Section 2339A are
themselves inchoate offenses—for instance, 18 U.S.C. § 956(a)(1) proscribes conspiracies to kill,
kidnap, maim, or injure persons in a foreign country.51 Thus, Section 2339A can be used to punish
a conspiracy to provide material support or resources in furtherance of a crime that is itself a
conspiracy to take further unlawful action, and such a charge will not be deemed an
impermissible “conspiracy to conspire.”52

41 United States v. Taleb-Jedi, 566 F. Supp. 2d 157, 179 (E.D.N.Y. 2008).
42 Cf. Holder v. Humanitarian L. Project, 561 U.S. 1, 17 (2010) (recognizing that Section 2339A “refer[s] to intent to
further terrorist activity”).
43 18 U.S.C. § 2339A(a).
44 CRS Report R42001, Attempt: An Overview of Federal Criminal Law, by Charles Doyle. Attempt and conspiracy in
relation to offenses that may be charged as domestic terrorism, as a general matter, are discussed infra, § “Inchoate and
Accomplice Liability.”
45 United States v. Farhane, 634 F.3d 127, 145 (2d Cir. 2011) (involving attempt to provide material support or
resources under Section 2339B).
46 United States v. Mehanna, 735 F.3d 32, 53 (1st Cir. 2013).
47 E.g., United States v. Suarez, 893 F.3d 1330, 1335 (11th Cir. 2018) (involving attempt to provide material support or
resources under Section 2339B).
48 CRS Report R41223, Federal Conspiracy Law: A Brief Overview, by Charles Doyle.
49 See 18 U.S.C. § 371 (requiring at least one of the conspirators to “do any act to effect the object of the conspiracy”);
Whitfield v. United States, 543 U.S. 209, 212 (2005) (acknowledging that Section 371 “expressly includes an overt-act
requirement”). An overt act is an outward, physical manifestation of intent to effect the conspiracy’s object. See Overt
Act, BLACK’S LAW DICTIONARY (11th ed. 2019).
50 E.g., United States v. Moalin, 973 F.3d 977, 1006-07 (9th Cir. 2020). A defendant charged with conspiracy may also
be charged with the substantive crime, if completed, as well as with other “reasonably foreseeable” crimes of co-
conspirators committed in furtherance of the conspiracy. United States v. Henry, 984 F.3d 1343, 1355 (9th Cir. 2021)
(quoting United States v. Long, 301 F.3d 1095, 1103 (9th Cir. 2002)); United States v. Abu Khatallah, 314 F. Supp. 3d
179, 188 (D.D.C. 2018).
51 18 U.S.C. § 956(a)(1).
52 United States v. Stewart, 590 F.3d 93, 118-19 (2d Cir. 2009).
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Violations of Section 2339A, including its attempt and conspiracy provisions, are punishable by
fine, imprisonment for up to 15 years, or both.53 If death results, punishment increases to
imprisonment for any term of years or for life.54
Material Support to Foreign Terrorist Organizations Under 18 U.S.C. § 2339B
18 U.S.C. § 2339B bears some similarities to Section 2339A, most notably in its core proscription
of providing “material support or resources” and associated definitions, but other details of the
two offenses vary considerably. Section 2339B prohibits “knowingly” providing, or attempting or
conspiring to provide, material support or resources “to a foreign terrorist organization.”55 Thus,
the focus of the statute is not on the use for which the support or resources are intended (as in
Section 2339A), but on the recipient or intended recipient.
The term “material support or resources” in Section 2339B has the same definition as under
Section 2339A, including the sub-definitions of “training” and “expert advice or assistance.”56
Thus, material support or resources under Section 2339B broadly include tangible or intangible
property, services, or “personnel.”57 However, Section 2339B includes additional provisions and
definitions related to the proscribed conduct that have been added over time in light of concern
that providing support to an organization may encompass advocacy or association protected by
the Constitution.58 Specifically, the statute stipulates that although providing personnel may
include providing oneself to aid a foreign terrorist organization, personnel must be provided “to
work under that terrorist organization’s direction or control or to organize, manage, supervise, or
otherwise direct the operation of that organization.”59 As such, persons “who act entirely
independently of the foreign terrorist organization to advance its goals” are not considered as
“working under the foreign terrorist organization’s direction and control.”60 Section 2339B
further makes clear that it is not to be “construed or applied so as to abridge the exercise of rights
guaranteed under the First Amendment,”61 and the Supreme Court has recognized that consistent
with First Amendment limitations, providing a “service” to an organization connotes activity
“performed in coordination with, or at the direction of,” the relevant organization.62 Accordingly,
Section 2339B does not proscribe pure political speech, independent advocacy, or “mere
association” with an organization—instead, it is limited to speech or conduct coordinated with, or
at least directed to, the organization itself.63

53 18 U.S.C. § 2339A(a). Terrorism sentencing enhancements are discussed in more detail infra, § “Domestic Terrorism
at Sentencing.”
54 18 U.S.C. § 2339A(a).
55 18 U.S.C. § 2339B(a)(1). Beyond the core criminal proscription, Section 2339B addresses a number of related
matters that are beyond the scope of this report, including establishing a reporting requirement for financial institutions
that hold funds for a foreign terrorist organization, establishing extraterritorial jurisdiction, structuring investigations,
and protecting classified information. See id. § 2339B(a)(2)-(f).
56 Id. § 2339B(g)(4).
57 Id. § 2339A(b)(1).
58 Constitutional issues related to domestic terrorism, including First Amendment concerns, are discussed infra,
§ “Constitutional Issues.”
59 18 U.S.C. § 2339B(h).
60 Id.
61 Id. § 2339B(i).
62 Holder v. Humanitarian L. Project, 561 U.S. 1, 24 (2010) (noting that “[t]he use of the word ‘to’ indicates a
connection between the service and the foreign group”).
63 E.g., United States v. Nagi, 254 F. Supp. 3d 548, 557-58 (W.D.N.Y. 2017); United States v. Elshinawy, 228 F. Supp.
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Material support or resources must be provided “to a foreign terrorist organization,”64 and the
statute defines a “terrorist organization” as an organization designated under Section 219 of the
Immigration and Nationality Act.65 That provision, codified at 8 U.S.C. § 1189, authorizes the
Secretary of State to designate an organization as a foreign terrorist organization if he or she finds
that (1) the organization is foreign, (2) the organization engages in terrorist activity or terrorism66
or “retains the capability and intent to engage in terrorist activity or terrorism,” and (3) “the
terrorist activity or terrorism of the organization threatens the security of United States nationals
or the national security of the United States.”67 The remainder of Section 1189 sets out detailed
procedures for designation, its effects, amendments to a designation, revocation of a designation
by the Secretary or Congress, and review of a designation by the Secretary or the courts.68 A
designation may not be challenged, however, in a criminal proceeding by a defendant who is
alleged to have violated Section 2339B.69
Material support or resources under Section 2339B must be provided “knowingly,”70 and a
clarifying amendment passed in 200471 elaborates that to meet this mental-state requirement, the
defendant must have knowledge that the organization (1) is a designated terrorist organization (as
described in the preceding paragraph), (2) “has engaged or engages in terrorist activity,” or (3)
“has engaged or engages in terrorism.”72 The terms “terrorist activity” and “terrorism” are defined
by reference to two separate statutes: 8 U.S.C. § 1182(a)(3)(B), which defines “terrorist activity”
as “any activity which is unlawful under the laws of the place where it is committed (or which, if
it had been committed in the United States, would be unlawful under the laws of the United States
or any State) and which involves” specific kinds of conduct including, among other things,
hijacking or sabotage, assassination, or use of certain weapons with intent to endanger individual
safety or cause substantial damage to property;73 and 22 U.S.C. § 2656f(d)(2), which defines
“terrorism” as “premeditated, politically motivated violence perpetrated against noncombatant
targets by subnational groups or clandestine agents.”74 As it relates to the requisite mental state
under Section 2339B, the import of these references is that liability depends on “knowledge about

3d 520, 536 (D. Md. 2016). Section 2339B also contains an exception to criminal liability “in connection with the term
‘personnel’, ‘training’, or ‘expert advice or assistance’ if the provision of that material support or resources to a foreign
terrorist organization was approved by the Secretary of State with the concurrence of the Attorney General,” though
approval may not be given for material support “that may be used to carry out terrorist activity.” 18 U.S.C. § 2339B(j).
64 Id. § 2339B(a)(1).
65 Id. § 2339B(g)(6).
66 The terms “terrorist activity” and “terrorism” are defined in separate statutes, as described infra.
67 8 U.S.C. § 1189(a). The statute requires consultation with the Secretary of the Treasury and the Attorney General. Id.
§ 1189(d)(4).
68 See id. § 1189(a)(2)-(c).
69 See United States v. Ali, 799 F.3d 1008, 1019 (8th Cir. 2015); United States v. Afshari, 426 F.3d 1150, 1155 (9th
Cir. 2005).
70 18 U.S.C. § 2339B(a)(1).
71 Holder v. Humanitarian L. Project, 561 U.S. 1, 12 (2010).
72 18 U.S.C. § 2339B(a)(1).
73 8 U.S.C. § 1182(a)(3)(B)(iii)(I)-(VI). The same statute separately defines the term “engage in terrorist activity” as
participation in terrorist activity in various ways, e.g., preparing or planning it, soliciting funds or other things of value
for it, or gathering information on particular targets for it. Id. § 1182(a)(3)(B)(iv).
74 22 U.S.C. § 2656f(d)(2).
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the organization’s connection to terrorism,” but “specific intent to further the organization’s
terrorist activities” is not required.75
As with Section 2339A, Section 2339B also criminalizes attempts and conspiracies to provide
material support or resources, and the requirements are similar.76 Violations of Section 2339B’s
material support proscription, including through attempt or conspiracy, are punishable by fine,
imprisonment for up to 20 years, or both.77 If death results, however, punishment increases to
imprisonment for any term of years or for life.78
Terrorism Transcending National Boundaries: 18 U.S.C. § 2332b
Prohibited Acts and Penalties
18 U.S.C. § 2332b proscribes specific kinds of violent acts and damage to property within the
United States where “conduct transcending national boundaries” is involved and certain
jurisdictional prerequisites are met.79 The statute imposes criminal penalties for (1) killing,
kidnapping, maiming, committing an assault resulting in serious bodily injury, or assaulting with
a dangerous weapon any person within the United States; or (2) creating a “substantial risk of
serious bodily injury to any other person” by destroying, damaging, or attempting or conspiring to
destroy or damage property within the United States, where either (1) or (2) is committed “in
violation of the laws” of a state or the United States.80 These proscriptions apply only when
“conduct transcending national boundaries” is involved and at least one of six jurisdictional
circumstances, such as a connection to interstate or foreign commerce, is present.81 Threats,
attempts, and conspiracies to violate the substantive provisions of Section 2332b are also
prohibited.82
Reported cases involving Section 2332b offenses are relatively few, and thus there is little judicial
guidance on many of the statutory elements.83 That said, although Section 2332b is sometimes

75 Holder, 561 U.S. at 16-17.
76 See supra notes 43-52 and accompanying text.
77 18 U.S.C. § 2339B(a)(1). Terrorism sentencing enhancements are discussed in more detail infra, § “Domestic
Terrorism at Sentencing.”
78 18 U.S.C. § 2339B(a)(1).
79 Id. § 2332b(a)(1).
80 Id. It appears that the “in violation of the laws” requirement calls for identification of a separate federal or state
criminal provision that the killing or other identified conduct violates. E.g., Superseding Information at 2, United States
v. Arbabsiar, No. 11-CR-897 (S.D.N.Y. Oct. 17, 2012) (specifically referencing 18 U.S.C. § 1116). A separate
subsection of Section 2332b supports this reading by clarifying that when a prosecution “is based upon the adoption of
State law, only the elements of the offense under State law, and not any provisions pertaining to criminal procedure or
evidence, are adopted.” 18 U.S.C. § 2332b(d)(2).
81 18 U.S.C. §§ 2332b(a)(1), (b).
82 Id. § 2332b(a)(2). The separate proscription regarding attempt and conspiracy creates an oddity, and perhaps
redundancy, with respect to Section (a)(1)(B), as that provision prohibits creating a substantial risk of serious bodily
injury by destroying, damaging, or attempting or conspiring to destroy or damage property. Id. § 2332b(a)(1)(B). Thus,
read together, the provisions appear to prohibit, among other things, attempting or conspiring to create a substantial risk
of serious bodily injury by attempting or conspiring to destroy or damage property. It appears that in at least one case,
federal prosecutors charged violations of both Section (a)(1)(B) and Section (a)(2) based on a solo plot to blow up a
courthouse, though the Section (a)(2) charge may have been based on a threat the defendant made regarding the plot.
See United States v. Nesgoda, 199 F. App’x 114, 115 (3d Cir. 2006) (unpublished).
83 Beyond the offenses described, Section 2332b contains other provisions addressing extraterritorial jurisdiction,
investigative authority, and the definition of a list of “federal crimes of terrorism” that have legal implications
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characterized as an “international terrorism” provision,84 it appears that its offenses may
encompass conduct meeting the statutory definition of “domestic terrorism” in the sense that they
address acts dangerous to human life, in violation of state or federal criminal law, that may be
intended to intimidate civilians or influence or affect the policy or conduct of a government85 and
occur “primarily within the territorial jurisdiction of the United States.”86 In this last respect,
Section 2332b defines “conduct transcending national boundaries” to mean “conduct occurring
outside of the United States in addition to the conduct occurring in the United States,”87 but at
least one case involving a conspiracy under Section 2332b(a)(2) appears to support a fairly
limited reading of that requirement. In United States v. Wright, a U.S. resident was charged under
Section 2332b’s conspiracy provision based on his participation in a plot to, among other things,
kill a U.S. citizen within the United States for insulting the Prophet Mohammed.88 The “conduct
transcending national boundaries” in the case was primarily a co-conspirator’s exchange of
information online with someone located outside the United States.89 The defendant argued that
“mere communications” were insufficient to meet the statutory element of conduct transcending
national boundaries because such conduct must be criminal, but the trial court disagreed,90 and
the U.S. Court of Appeals for the First Circuit affirmed.91 The appellate court stated that even
assuming the requisite conduct must be “substantial” to constitute conduct transcending national
boundaries, the foreign resident’s provision to the co-conspirator of “research and guidance on
the plot to kill” the U.S. citizen sufficed.92
It is not clear whether a defendant must know of conduct transcending national boundaries to
violate Section 2332b, so long as such conduct occurs. The statute states that proof of
“knowledge by any defendant of a jurisdictional base alleged in the indictment is not required,”93
and in Wright, the trial court treated the phrase “involving conduct transcending national
boundaries” as establishing only a jurisdictional element for which no proof of mental state was
necessary.94 That said, the appellate court in the case appeared to assume that at least knowledge
of the conduct transcending national boundaries was required.95

addressed elsewhere in this report.
84 E.g., Harry Litman, A Domestic Terrorism Statute Doesn’t Exist. Congress Must Pass One app Now, WASH. POST
(Aug. 5, 2019), https://www.washingtonpost.com/opinions/2019/08/05/domestic-terrorism-statute-doesnt-exist-
congress-must-pass-one-now/ (“18 U.S. Code § 2332b lays out a laundry list of ‘acts of terrorism transcending national
boundaries,’—i.e., acts of international terrorism—with commensurately serious penalties, including sentences of
death.”).
85 A violation of Section 2332b does not depend on any particular ideological motive, and thus a purpose to intimidate
civilians or impact a government could underlie conduct charged in a Section 2332b case but would not be required.
86 18 U.S.C. § 2331(5).
87 Id. § 2332b(g)(1).
88 285 F. Supp. 3d 443, 447-49 (D. Mass. 2018).
89 Id. at 459-60.
90 Id. at 460.
91 United States v. Wright, 937 F.3d 8, 33 (1st Cir. 2019).
92 Id.
93 18 U.S.C. § 2332b(d)(1). Proof of mens rea (a requisite mental state) is undoubtedly required with respect to the non-
jurisdictional conduct prohibited in Section 2332b. See, e.g., Staples v. United States, 511 U.S. 600, 605 (1994)
(“[S]ilence . . . by itself does not necessarily suggest that Congress intended to dispense with a conventional mens rea
element, which would require that the defendant know the facts that make his conduct illegal.”).
94 285 F. Supp. 3d at 460. Regardless, the trial court determined that “[t]he evidence presented at trial showed that [the
defendant] and his coconspirators knew that the conspiracy involved conduct that transcended national boundaries.” Id.
95 937 F.3d at 37 (finding no “clear and obvious” error in the jury instruction regarding what Wright “needed to ‘know
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Maximum penalties for violations of Section 2332b depend on the conduct involved. If a death
results, the death penalty or imprisonment for up to life is authorized.96 Kidnapping is punishable
by up to life in prison, maiming by up to 35 years, assault with a dangerous weapon or resulting
in serious bodily injury by up to 30 years, destruction of property by up to 25 years, attempt or
conspiracy by up to the maximum punishment applicable for a completed offense, and threat by
up to 10 years.97
Definition of “Federal Crime of Terrorism” in § 2332b(g)
Separate from the offense established in Section 2332b, the statute also defines a list of over fifty
federal offenses (including the Section 2332b offense) that are “federal crime[s] of terrorism” if
“calculated to influence or affect the conduct of government by intimidation or coercion, or to
retaliate against government conduct.”98 Some of the listed offenses are those found in Chapter
113B itself, while others are in different chapters of Title 18 or other titles of the U.S. Code.99
Although located in the statutory section denominated “[a]cts of terrorism transcending national
boundaries,” the definition does not require that a listed offense with the requisite purpose
involve transnational conduct in order to be considered a “federal crime of terrorism.”100 Section
2332b also does not establish separate criminal penalties for “federal crimes of terrorism,” but the
definition is used for other purposes—notably, (1) the Attorney General is given primary
investigative responsibility for all “federal crimes of terrorism,”101 (2) the listed offenses are
incorporated as predicate offenses under the “material support” provision in Section 2339A,102
and (3) the term is incorporated in an adjustment under the U.S. Sentencing Guidelines that can
increase a Guidelines sentence range if the offense at issue involved or sought to promote a
“federal crime of terrorism.”103 The latter two aspects of the “federal crime of terrorism”
definition are discussed in the separate sections of this report addressing those topics.
Remaining Chapter 113B Offenses
Beyond the three broader “material support” and “transcending national boundaries” terrorism
offenses in Chapter 113B, the remaining offenses address specific kinds of conduct such as using
particular weapons or providing financing in service of terrorist acts. Some of these other Chapter

specifically,’” and no error in the court’s instruction that the government had to establish that “Wright ‘reasonably
understood that he was engaged in a conspiracy to do conduct that transcends national boundaries’”). Because Wright
involved a conspiracy, it was not disputed that the defendant had to have the “specific intent” to accomplish the object
of the conspiracy. Id. at 36.
96 18 U.S.C. § 2332b(c)(1)(A).
97 Id. §§ 2332b(c)(1)(B)-(G). Probation is prohibited, and a term of imprisonment under Section 2332b must run
consecutive to any other term of imprisonment. Id. § 2332b(c)(2). Terrorism sentencing enhancements are discussed in
more detail infra, § “Domestic Terrorism at Sentencing.”
98 Id. § 2332b(g)(5).
99 A number of offenses outside of Chapter 113B that are defined as “federal crimes of terrorism” and can apply to
domestic terrorism are discussed infra, § “Other Federal Criminal Laws Applicable to Domestic Terrorism.”
100 United States v. Salim, 549 F.3d 67, 79 (2d Cir. 2008). That said, the listed offenses may themselves bear a
transnational conduct element or otherwise include an international component.
101 18 U.S.C. § 2332b(f).
102 Id. § 2339A(a). Exception is made for the “material support” provisions in Sections 2339A and 2339B, apparently
to avoid redundancy. Id.
103 U.S. SENT’G GUIDELINES MANUAL § 3A1.4 (U.S. SENT’G COMM’N 2018).
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113B offenses have limitations making them applicable only to international terrorism or conduct
abroad, but many may be applicable, at least in part, to domestic-focused conduct.
In the former category, 18 U.S.C. § 2332 proscribes homicide (as well as attempt and conspiracy)
and other violent acts outside the United States against U.S. nationals, where the Attorney
General or a high-ranking subordinate certifies that the offense was “intended to coerce,
intimidate, or retaliate against a government or a civilian population.”104 Section 2332d prohibits
a U.S. person from engaging in a financial transaction with the government of a country
designated as “supporting international terrorism,” if the person knows or has reasonable cause to
know that the country is so designated.105 Section 2332f prohibits bombing public spaces,
government or infrastructure facilities, or public transportation systems with intent to cause death,
serious bodily injury, or extensive destruction likely to result in major economic loss.106 A lengthy
list of jurisdictional prerequisites in Section 2332f makes clear that if the offense takes place in
the United States, there must be some link to a foreign state or foreign national or stateless
person, or a perpetrator must be found outside the United States.107 Finally, Section 2339D makes
it a crime to knowingly receive “military-type training”108 from or on behalf of an organization
designated at that time as a foreign terrorist organization, provided at least one of a number of
jurisdictional prerequisites is met.109 Designation is made under the same authorities previously
discussed in connection with Section 2339B, and the mental state requirement is the same as
well—i.e., a person must have knowledge that the organization is either so designated, has
engaged or engages in terrorist activity, or has engaged or engages in terrorism, as defined under
separate legal provisions.110

104 18 U.S.C. § 2332(a)-(d).
105 Id. § 2332d(a).
106 Id. § 2332f(a)(1). The specific conduct prohibited is unlawfully delivering, placing, discharging, or detonating an
explosive or other lethal device in, into, or against a place of public use, a state or government facility, a public
transportation system, or an infrastructure facility. Id. Attempts and conspiracies are also proscribed. Id. § 2332f(a)(2).
Beyond the exception noted in footnote 107, infra, additional exception is made for activities of armed forces during
armed conflict and activities undertaken by military forces in the exercise of official duties. Id. § 2332f(d)(1)-(2).
107 The one jurisdictional prerequisite that potentially could apply to purely domestic-focused conduct is that the
offense occurs in the United States and “is committed in an attempt to compel . . . the United States to do or abstain
from doing any act.” Id. § 2332f(b)(1)(B). However, even then, a separate exception states that, among other things,
Section 2332f does not apply to offenses committed within the United States “where the alleged offender and the
victims are United States citizens and the alleged offender is found in the United States.” Id. § 2332f(d)(3). That said,
conduct that takes place in the United States and may meet the statutory definition of domestic terrorism can still come
within the purview of Section 2332f if the offender or at least one victim is a foreign national and the offense has a
substantial effect on interstate or foreign commerce. See, e.g., Indictment (Original & Last Amended/Superseded),
United States v. Tsarnaev, 968 F.3d 24 (1st Cir. 2020) (No. 16-6001), 2013 WL 3215742 (in case involving domestic
bombing by naturalized U.S. citizen, alleging that a victim was a national of another country and the offense had a
substantial effect on interstate and foreign commerce).
108 Military-type training is defined as including “training in means or methods that can cause death or serious bodily
injury, destroy or damage property, or disrupt services to critical infrastructure, or training on the use, storage,
production, or assembly” of explosives, firearms, or “other weapons” such as weapons of mass destruction. Id.
§ 2339D(c)(1).
109 Id. § 2339D(a)-(b).
110 See id. § 2339D(a); supra notes 64-75 and accompanying text.
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In the latter category, Sections 2332a, 2332g, and 2332h largely prohibit the use of weapons of
mass destruction (WMDs),111 missile systems designed to destroy aircraft,112 and radiological
dispersal devices, respectively.113 Section 2332i restricts possession or use of radioactive material
and radioactive/radiation-emitting/nuclear explosive devices with intent to cause certain harms or
to compel the acts of others.114 All of these offenses require that at least one of a number of
jurisdictional prerequisites is present, and while many of the prerequisites address conditions
existing or directed outside the United States, others relate to domestic-focused circumstances—
for instance, 2332a, 2332g, and 2332h can apply domestically if a connection to interstate
commerce exists,115 and Section 2332i jurisdiction exists if the prohibited conduct simply takes
place in the United States,116 among many other things. Likewise, Section 2339 prohibits
harboring or concealing a person that the offender knows, or has reasonable grounds to believe,
has committed or is about to commit one of several listed offenses that can apply domestically,
such as arson and bombing of government property risking or causing injury or death (18 U.S.C.

111 18 U.S.C. § 2332a. Use of WMDs against persons or property “without lawful authority,” as well as threats,
attempts, and conspiracies to do the same, are prohibited. Id. § 2332a(a). One federal appellate court has described the
“without lawful authority” element as being “intended to except persons who are authorized by the appropriate
authorities to use hazardous biological agents for legitimate purposes.” United States v. Wise, 221 F.3d 140, 149 (5th
Cir. 2000). A WMD is defined as a destructive device (including a bomb, grenade, mine, certain rockets and missiles,
and similar devices); any weapon designed or intended to cause death or serious bodily injury through toxic or
poisonous chemicals or precursors; any weapon involving a biological agent, toxin, or vector; or any weapon that is
designed to release radiation or radioactivity at a level dangerous to human life. 18 U.S.C. § 2332a(c)(2). Other
criminal prohibitions listed as “federal crimes of terrorism” but found outside of Chapter 113B can also apply to similar
kinds of weapons or substances. See, e.g., 18 U.S.C. § 175(a) (prohibiting knowing development, production,
stockpiling, transfer, acquisition, retention, or possession of “any biological agent, toxin, or delivery system for use as a
weapon”).
112 Specifically, the statute prohibits knowingly producing, constructing, otherwise acquiring, transferring, receiving,
possessing, importing or exporting, using, or possessing and threatening to use an explosive or incendiary rocket or
missile designed to destroy aircraft (unless not designed for use as a weapon), a device for launching such a rocket or
missile, or any part to be used in assembling the same. Id. § 2332g(a)(1)-(2). Attempts and conspiracies are also
proscribed. Id. § 2332g(c)(1). Exception is made for federal or state government conduct and conduct pursuant to the
terms of a government contract. Id. § 2332g(a)(3).
113 The provision prohibits knowingly producing, constructing, otherwise acquiring, transferring, receiving, possessing,
importing or exporting, using, or possessing and threatening to use weapons, devices, or objects that are designed or
intended to release radiation or radioactivity at a level dangerous to human life or that can endanger human life through
release of the same. Id. § 2332h(a)(1). Attempts and conspiracies are also proscribed. Id. § 2332h(c)(1). Exception is
made for federal government conduct or conduct pursuant to the terms of a federal government contract. Id.
§ 2332h(a)(2).
114 Specifically, the statute prohibits knowingly and unlawfully (1) possessing radioactive material or making or
possessing a “device” with intent to cause death, serious bodily injury, or substantial damage to property or the
environment; or (2) using radioactive material or a “device” or causing certain radioactive risk or releases from a
nuclear facility with intent to cause death, serious bodily injury, or substantial damage to property or the environment
(or knowing that the same is likely) or to compel a person, international organization, or country to act or refrain from
acting. Id. § 2332i(a)(1). A “device” is defined separately as a nuclear explosive device or radioactive material
dispersal or radiation-emitting device that may cause death, serious bodily injury or substantial damage to property or
the environment. Id. § 2332i(e)(2). A threat to do any of the above “under circumstances in which the threat may
reasonably be believed” or a demand to possess or access radioactive material, a device, or a nuclear facility by threat
or use of force are also proscribed, as are attempts and conspiracies. Id. § 2332i(a)(2)-(3). Exception is made for the
activities of armed forces during armed conflict and activities undertaken by military forces in the exercise of official
duties. Id. § 2332i(d).
115 See id. § 2332a(a)(2) (prohibition applies against persons or property within the United States if one of several links
to interstate or foreign commerce exists); id. § 2332g(b)(1) (jurisdiction exists if offense occurs in or affects interstate
or foreign commerce); id. § 2332h(b)(1) (same).
116 Id. § 2332i(b)(1).
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§ 844(f), discussed infra) or using a WMD (18 U.S.C. § 2332a, discussed supra).117 Lastly,
Section 2339C prohibits “unlawfully and willfully”118 providing or collecting funds with the
intention or knowledge that such funds will be used to carry out either (1) an act in violation of
certain international treaties, or (2) any other act intended to cause death or serious bodily injury
to a civilian, or to a person not taking active part in the hostilities in a situation of armed conflict,
when the purpose of the act “by its nature or context” is to intimidate a population or compel a
government or international organization to act or refrain from acting.119 Among other
circumstances giving rise to jurisdiction over the offense, jurisdiction exists if the offense takes
place in the United States and is directed toward or results in carrying out a predicate act (i.e., an
act in violation of one of the specified treaties or intended to cause death or serious bodily injury
with the stated conditions) also within the United States, so long as either the offense or predicate
act bears a sufficient connection to interstate commerce.120
Other Federal Criminal Laws Applicable to
Domestic Terrorism
As discussed above, some, but not all, federal criminal laws that expressly address terrorism can
apply in the context of domestic terrorism.121 Additionally, depending on the circumstances,
conduct that fits within the legal definition of domestic terrorism could violate any number of
generally applicable federal criminal laws ranging from hate crime statutes to provisions
protecting government property. General principles of inchoate and accomplice liability may also
expand the reach of these laws and the terrorism-specific statutes discussed previously. Finally,
performing acts connected to or considered to be domestic terrorism can impact the sentence
imposed for committing these and other federal offenses.
Substantive Criminal Laws
Some observers estimate that dozens of federal criminal statutes could apply to domestic
terrorism,122 and it is possible to envision examples of domestic terrorism that might violate

117 Id. § 2339(a).
118 One court has noted that the term “unlawfully” is meant to “embody common law defenses.” N.Y. Times Co. v.
DOJ, 756 F.3d 100, 126 n.10 (2d Cir. 2014) (reviewing legislative history). Caselaw appears to provide little
elaboration on the term “willfully” as used in Section 2339C, and the word is a “notoriously slippery” one in general.
United States v. Starnes, 583 F.3d 196, 210 (3d Cir. 2009) (quoting United States v. Ladish Malting Co., 135 F.3d 484,
487-88 (7th Cir. 1998)). In an unpublished opinion, one court suggested in passing that the standard of “unlawfully and
willfully” in Section 2339C is “arguably higher” than knowledge. Hussein v. Dahabshiil Transfer Servs. Ltd., 705 F.
App’x 40, 41 (2d Cir. 2017) (summary order).
119 Id. § 2339C(a)(1). It is not necessary that the so-called predicate act for which funds are collected or provided
actually occur. Id. § 2339C(a)(3). Attempts and conspiracies are also proscribed. Id. § 2339C(a)(2). Separately, Section
2339 prohibits knowingly concealing funds, proceeds, or “material support or resources” knowing or intending that
they are or were provided or collected in violation of Section 2339C or, in the case of material support or resources, in
violation of Section 2339B (addressing support to foreign terrorist organizations, discussed supra).
120 Id. § 2339C(b)(1)(G)(ii). Other domestic-focused jurisdictional circumstances exist, such as when a predicate act
seeks to compel the United States to do or abstain from doing any act. Id. § 2339C(b)(5).
121 Supra, § “Federal Criminal Terrorism Laws.”
122 See GERMAN & ROBINSON, supra note 21, at 6-7, 10-12.
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tangentially-relevant criminal laws.123 Given the large number of federal criminal laws,124 a
comprehensive review is beyond the scope of this report. Instead, this section overviews the basic
categories of federal statutes that could implicitly criminalize acts of domestic terrorism,125
including:
 Crimes of violent unrest,
 Crimes against government authority,
 Crimes against persons,
 Crimes involving infrastructure or federal property,
 Hate crimes,
 Crimes involving specific weapons,
 Crimes involving threats, and
 Crimes involving computers.
Acts of domestic terrorism, however, may not fit neatly within a single category. In the past, acts
of domestic terrorism have resulted in charges under multiple statutes126—and many relevant
statutes could plausibly fall within multiple categories.127 But the categories provide clarity and
illustrate how underlying conduct may inform federal prosecutors’ selection of charges, and the
broader designation of the crime.128 For example, the choice of statute might depend on, among

123 For example, according to analysis by one observer, DOJ used a statute prohibiting “manufacturing, distributing or
dispensing a controlled substance” as the lead charge in four domestic terrorism prosecutions between the 2013 and
2017 financial years. Id. at 10.
124 See John G. Malcolm, Morally Innocent, Legally Guilty: The Case for Mens Rea Reform, 18 FEDERALIST SOC’Y
REV. 40, 41 (2017) (estimating that there are approximately 5,000 federal statutes carrying criminal penalties). This
number does not include federal regulations that implicate criminal penalties, which may number over 300,000. Id.
125 Other statutes might be used to target groups engaged in domestic terrorism more generally. For example, some
observers have suggested that the Racketeer Influenced and Corrupt Organizations Act (RICO)—often associated with
prosecutions in the organized crime context—may be useful in prosecuting groups engaged in domestic terrorism. See,
e.g., Francesca Laguardia, Considering A Domestic Terrorism Statute and Its Alternatives, 114 NW. U. L. REV. 1061,
1093 (2020) (“The possibility of using RICO, . . . the organized crime law enforcement powerhouse, to pursue
terrorists, has been floated in legal scholarship since at least 1990.”). For more information on RICO see generally CRS
Report 96-950, RICO: A Brief Sketch, by Charles Doyle. Statutes criminalizing financial crimes such as money
laundering could also potentially be applicable to certain aspects of the financing of domestic terrorism. See generally
CRS Testimony TE10056, A Persistent and Evolving Threat: An Examination of the Financing of Domestic Terrorism
and Extremism, by Rena S. Miller. For legal analysis of money laundering statutes see generally CRS Report RL33315,
Money Laundering: An Overview of 18 U.S.C. § 1956 and Related Federal Criminal Law, by Charles Doyle.
126 For example, in connection with an incident described by DOJ as a domestic terrorist attack, prosecutors charged
one individual under several statutes, including those prohibiting interstate transportation or receipt of explosives,
interstate threats, and illegal mailing of explosives. Press Release, U.S. Dep’t of Justice, Cesar Sayoc Pleads Guilty to
65 Felonies for Mailing 16 Improvised Explosive Devices in Connection with October 2018 Domestic Terrorist Attack
(Mar. 21, 2019), https://www.justice.gov/opa/pr/cesar-sayoc-pleads-guilty-65-felonies-mailing-16-improvised-
explosive-devices-connection [hereinafter Sayoc Plea Press Release]; Press Release, U.S. Dep’t of Justice, Cesar
Altieri Sayoc Charged in 30-Count Indictment With Mailing Improvised Explosive Devices in Connection With
Domestic Terrorist Attack (Nov. 9, 2018), https://www.justice.gov/opa/pr/cesar-altieri-sayoc-charged-30-count-
indictment-mailing-improvised-explosive-devices.
127 E.g., 18 U.S.C. § 175 (restricting use of specific weapons (biological agents) and prohibiting certain threats
involving them (§ 175 is a predicate offense for 18 U.S.C. § 2339A discussed above)); id. § 245(b)(2) (prohibiting
certain hate crimes and authorizing increased penalties where defendant uses specific weapon (dangerous weapons) in
committing hate crime); id. § 247 (prohibiting various hate crimes and protecting both certain persons and property);
49 U.S.C. § 46505 (criminalizing certain conduct involving specific weapons (firearms or explosives) when it involves
infrastructure (aircraft) (§§ 46505(b)(3) and (c) are predicate offenses for 18 U.S.C. § 2339A discussed above)).
128 See, e.g., FBI Oversight Hearing, supra note 2 (statement of Christopher Wray, Dir., FBI) (“We [the FBI] focus on
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other things,129 the weapon used by the defendant (e.g., biological agents under 18 U.S.C. §
175),130 the target selected (e.g., federal property under 18 U.S.C. § 1361),131 or the defendant’s
motive (e.g., bias against the victim’s race under 18 U.S.C. § 249(a)(1)).132 Relatedly, such
circumstances may also determine whether there is federal jurisdiction, rather than state or local,
to investigate or prosecute conduct that could be described as domestic terrorism.133
Crimes of Violent Unrest
In recent months, high-ranking law enforcement officials have expressed concern over the
possible intersection of domestic terrorism and violent unrest, such as rioting and other
destructive mob behavior.134 For example, in a March 2, 2021 Senate Judiciary Hearing, Federal
Bureau of Investigation (FBI) Director Christopher Wray described some of the conduct
committed during the events of January 6, 2021 at the U.S. Capitol—such as the breaching of
Capitol grounds and “violence against law enforcement”—as domestic terrorism.135 According to
Wray, the incident involved lawful protesters, as well as individuals who came to “be part of a
peaceful protest” but who engaged in “low-level criminal behavior” after being “swept up in . . .
motive or emotion.”136 Law enforcement officials have indicated that the events of January 6
illustrate the potential for domestic terrorists to use social unrest as a weapon, by “turning large
groups of people to violence.”137 As such, there are a number of federal criminal statutes that
could be relevant when individuals participate in violent unrest, including the federal anti-riot act
and civil disorder statute. This section discusses both in turn.

the violence and the violation of federal law. And then the ideology comes into it as a further piece of the puzzle as we
build up the case.”).
129 For example, DOJ policy is generally to charge the most serious applicable offense, although typically “a defendant
will have committed more than one criminal act and his/her conduct may be prosecuted under more than one statute.”
DOJ Manual: Criminal §§ 9-27.300, https://www.justice.gov/jm/jm-9-27000-principles-federal-prosecution#9-27.300.
130 See Sinnar, supra note 4, at 1352 (explaining how the weapon used by a suspect may impact charging decisions in
domestic terrorism context).
131 See, e.g., Debra Cassens Weiss, 9th Circuit upholds part of federal anti-riot law in case against white supremacists,
ABA JOURNAL (Mar. 5, 2021), https://www.abajournal.com/news/article/9th-circuit-upholds-part-of-federal-anti-riot-
law-in-case-against-white-supremacists (speculating that because the events of January 6, 2021 at the Capitol “took
place on federal property and involved federal personnel,” the “government hasn’t had to use the [anti-riot act] against
people who participated” in the events).
132 See, e.g., Hate Crimes, FBI, https://www.fbi.gov/investigate/civil-rights/hate-crimes (last visited Mar. 29, 2021)
(explaining how “an added element of bias” may turn a “traditional offense like murder, arson, or vandalism” into a
hate crime).
133 See generally, What We Investigate, FBI, https://www.fbi.gov/investigate (last visited Apr. 7, 2021).
134 See, e.g., Press Release, U.S. Dep’t of Justice, Attorney General William P. Barr's Statement on Riots and Domestic
Terrorism (May 31, 2020), https://www.justice.gov/opa/pr/attorney-general-william-p-barrs-statement-riots-and-
domestic-terrorism (describing certain violence connected to rioting as domestic terrorism and stating that “the voices
of peaceful and legitimate protests have been hijacked by violent radical extremists”).
135 See, e.g., FBI Oversight Hearing, supra note 2(statement of Christopher Wray, Dir., FBI).
136 Id.
137 Lisa Desjardins, FBI director sounds the alarm on the growing threat of domestic terrorism, PBS (Mar. 2, 2021),
https://www.pbs.org/newshour/show/fbi-director-sounds-the-alarm-on-the-growing-threat-of-domestic-terrorism.
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Anti-Riot Act: 18 U.S.C. § 2101
The anti-riot act, 18 U.S.C. § 2101, has been used to prosecute conduct such as looting, setting
fires, distributing explosives,138 and assaulting protestors139 at rallies or demonstrations. Section
2101 imposes fines and up to five years of imprisonment for traveling in, or using a facility of,
interstate commerce with intent to do one of four activities: (1) incite a riot, (2) organize,
promote, encourage, or participate in, or carry on a riot, (3) commit any act of violence in
furtherance of a riot, or (4) aid or abet any person in such activities.140 The statute defines riots as
“a public disturbance involving” violent acts, or certain threats of violence, by at least one
individual who is “part of an assemblage of three or more persons,” where such acts or threats
result in, or “constitute a clear and present danger of,” property damage or injury to another.141
The statute defines inciting, organizing, promoting, encouraging, participating in, or carrying on a
riot to mean “urging or instigating other persons to riot.”142 That definition specifically excludes
advocacy of ideas or oral or written expression of beliefs that do not advocate violence.143
Although a potentially broad range of conduct could violate the anti-riot act, several limitations
curtail its applicability. First, as noted, the law does not govern conduct lacking an interstate
commerce nexus.144 Second, the statute requires that while traveling in, or using a facility of,
interstate commerce, the suspect engage in an overt act145—an outward manifestation of intent to
commit a crime.146 In practice, those overt acts appear to overlap with the four prohibited
activities listed above.147 Overt acts can include, for example, committing a violent act in
furtherance of a riot.148 Third, the statute applies only to intentional conduct, and courts have
construed the anti-riot act to “require[] the government to prove a defendant’s intent [to engage in
a prohibited purpose] at two points in time:” (1) “when the defendant [travels in or] uses a facility
of interstate commerce with the intent to incite a riot,” and (2) “when the defendant commits an
overt act . . . .”149 Fourth, at least one federal court has imposed causality requirements between
the defendant’s conduct and the riot, requiring that the defendant’s conduct be “sufficiently
closely related as a propelling cause of a riot,” and not a mere attenuated link.150 Finally, there

138 E.g., Criminal Complaint, United States v. Rupert, No. 20-mj-344 (D. Minn. 2020).
139 See, e.g., Press Release, U.S. Dep’t of Justice, Remaining Members of California-Based White Supremacist Group
Plead Guilty to Federal Rioting Charges in Connection with August 2017 “Unite the Right” Rally in Charlottesville
(May 3, 2019), https://www.justice.gov/usao-wdva/pr/remaining-members-california-based-white-supremacist-group-
plead-guilty-federal-rioting (describing guilty pleas entered by individuals who, among other things, “assaulted
protestors and other individuals” at a rally).
140 18 U.S.C. § 2101(a).
141 Id. § 2102(a).
142 Id. § 2102(b).
143 Id.
144 Id. § 2101(a); accord United States v. Daley, 378 F. Supp. 3d 539, 558 (W.D. Va. 2019), aff’d sub nom. United
States v. Miselis, 972 F.3d 518 (4th Cir. 2020) (determining that § 2101 “plainly requires that a defendant travel in or
use a facility of interstate or foreign commerce with the requisite intent”).
145 18 U.S.C. § 2101(a).
146 Overt Act, BLACK’S LAW DICTIONARY (11th ed. 2019).
147 See United States v. Rundo, No. 19-50189, 2021 WL 821938, at *4 (9th Cir. Mar. 4, 2021) (“We hold that the overt
act requirement refers to acts that fulfill the elements themselves, and not mere steps toward, or related to, one or more
of those elements.”).
148 E.g., Daley, 378 F. Supp. 3d at 560.
149 E.g., United States v. Markiewicz, 978 F.2d 786, 813 (2d Cir. 1992).
150 E.g., United States v. Dellinger, 472 F.2d 340, 361 (7th Cir. 1972).
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may be constitutional limitations on the application of the anti-riot act.151 At least two federal
appellate courts have held that to the extent Section 2101 prohibits urging, encouraging, or
promoting a riot, it is overbroad and unconstitutionally proscribes First Amendment protected
activity.152 In addition, these courts concluded that the statutory language restricting Section 2101
from applying to oral or written expression of beliefs advocating violence is unconstitutional,
because the effect is that Section 2101 prohibits advocacy of violence, and “the First Amendment
protects that kind of advocacy.”153 These courts did not strike down all of Section 2101, however,
but rather severed the portions deemed unconstitutional under the First Amendment.154
Civil Disorder: 18 U.S.C. § 231
Another federal criminal statute concerning violent unrest is the civil disorder statute, 18 U.S.C.
§ 231, which the Department of Justice (DOJ) has used to charge dozens of individuals in
connection with the events of January 6, 2021 at the Capitol.155 “Civil disorder” is a term of art
defined as a “public disturbance involving acts of violence by assemblages of three or more
persons, which causes an immediate danger of or results in” injury to the property or person of
another.156 Of note, section 231 imposes fines and a maximum prison term of five years for
“commit[ting] or attempt[ing] to commit any act to obstruct, impede, or interfere with” a fireman
or law enforcement officer “lawfully engaged in the lawful performance of his official duties”
during a civil disorder, assuming certain jurisdictional requirements are satisfied.157
Although there is minimal case law construing the statute, courts have identified various limiting
principles on its application. For example, the statute has been read to regulate violent physical
acts only and not to concern speech.158 In this vein, one federal appellate court upheld the civil
disorder conviction of a defendant who threw a cherry bomb at a line of police officers
responding to a fire at a riot.159 Several other factors limit the applicability of the civil disorder
statute. First, although it is silent on an intent requirement, courts have construed the civil
disorder statute to criminalize only intentional conduct.160 Second, like the anti-riot act discussed
above, the civil disorder statute has jurisdictional limitations on its reach.161 Specifically, the
statute requires either (1) conduct that “obstructs, delays, or adversely affects” interstate

151 See Rundo, 2021 WL 821938, at *5-6.
152 Id.; United States v. Miselis, 972 F.3d 518, 536-38 (4th Cir. 2020). These courts disagreed on whether § 2101’s
language prohibiting organizing a riot was similarly problematic. Compare Rundo, 2021 WL 821938, at *5 (“The verb
‘organize’ is similarly overbroad.”) with Miselis, 972 F.3d at 537-38 (“[S]peech tending to organize a riot under §
2101(a)(2), unlike that of encouraging and promoting a riot, doesn’t implicate mere advocacy of lawlessness, and may
thus be proscribed.”).
153 Rundo, 2021 WL 821938, at *6; accord Miselis, 972 F.3d at 537-39.
154 Rundo, 2021 WL 821938, at *3; Miselis, 972 F.3d at 541.
155 See Capitol Breach Cases, U.S. Dep’t of Justice (summarizing charges in prosecutions for conduct connected to the
events of January 6, 2021 at the U.S. Capitol), https://www.justice.gov/usao-dc/capitol-breach-cases (last visited Mar.
30, 2021) [hereinafter Capitol Breach Cases].
156 18 U.S.C. § 232(1).
157 Id. § 231(a)(3). Other subsections of the civil disorder statute prohibit other conduct such as demonstrating the use
of, or transporting in interstate commerce, certain weapons while “knowing or having reason to know or intending that
the same will be unlawfully employed for use in . . . a civil disorder.” Id. § 231(a)-(2).
158 United States v. Mechanic, 454 F.2d 849, 852 (8th Cir. 1971) (“[A]s we read it, § 231(a)(3) has no application to
speech, but applies only to violent physical acts.”).
159 Id. at 851, 57.
160 Id. at 854.
161 18 U.S.C. § 231(a)(3).
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commerce or the movement of an article in interstate commerce, or (2) the obstruction of “the
conduct or performance of any federally protected function . . . .”162 A “federally protected
function” includes any function or operation by any federal department, agency, instrumentality,
officer, or employee pursuant to federal law.163 Finally, although the statute provides a broad
definition of “law enforcement officer,” which may at times include federal, state, and military
personnel,164 the prosecutor bears the burden of establishing that law enforcement was acting
lawfully during the alleged statutory violation.165 At least one court has acquitted defendants of
civil disorder charges for interfering with officers where the prosecutor failed to establish that
those officers were acting within their lawful authority. 166
Crimes against Government Authority
As discussed, the statutory definition of domestic terrorism includes certain dangerous conduct
intended to influence government policy or intended to affect government conduct.167
Conceptually, then, it is possible to envision instances of domestic terrorism amounting to crimes
against government authority, such as treason, insurrection, or seditious conspiracy, though as
detailed below, limited case law and significant statutory limitations may curtail the practical
applicability of these statutes, and in practice prosecutors may gravitate towards other charges.168
Treason: 18 U.S.C. § 2381
Due to limited case law, the exact contours of the federal crime of treason are unclear.169 Treason
has been described as the “most serious offense” that may be committed against the
government.170 It is the only crime defined in the Constitution itself,171 which specifies that
treason “consist[s] only” of “levying War against” the United States or “adhering to their
Enemies, giving them Aid and Comfort.”172 That definition is codified in Section 2381 of Title 18
of the U.S. Code, which imposes fines and a minimum sentence of five years of imprisonment for
treason, and authorizes the death penalty.173 Treason prosecutions are rare—particularly since the

162 Id.
163 Id. § 232(3).
164 Id. § 232(7).
165 Id. § 231(3); accord United States v. Red Feather, 392 F. Supp. 916, 918 (D.S.D. 1975); United States v. McArthur,
419 F. Supp. 186, 192 (D.N.D. 1975), aff’d sub nom. United States v. Casper, 541 F.2d 1275 (8th Cir. 1976); United
States v. Jaramillo, 380 F. Supp. 1375, 1381 (D. Neb. 1974).
166 Jaramillo, 380 F. Supp. at 1381.
167 18 U.S.C. § 2331(5).
168 For example, despite speculation about their potential applicability, DOJ has so far not filed treason, insurrection, or
seditious conspiracy charges connected to the events of January 6, 2021 at the U.S. Capitol, Capitol Breach Cases,
supra note 155, although at least one federal prosecutor has reportedly stated that seditious conspiracy charges remain
possible. Katie Bennar, Evidence in Capitol Attack Most Likely Supports Sedition Charges, Prosecutor Says, N.Y.
TIMES (Mar. 21, 2021), https://www.nytimes.com/2021/03/21/us/politics/capitol-riot-sedition.html. Federal prosecutors
reportedly have also considered whether the insurrection statute could apply to the events of January 6, 2021 at the U.S.
Capitol. Press Release, U.S. Dep’t of Justice, Federal authorities investigating any potential violations of federal law by
residents of Southern District of Ohio at the U.S. Capitol (Jan. 7, 2021), https://www.justice.gov/usao-sdoh/pr/federal-
authorities-investigating-any-potential-violations-federal-law-residents.
169 Infra, note 174 and accompanying text.
170 Stephan v. United States, 133 F.2d 87, 90 (6th Cir. 1943).
171 Id.
172 U.S. CONST. art. III, § 3, cl. 1.
173 18 U.S.C. § 2381.
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1950s.174 That said, there are a number of significant limits on applying the treason statute. First,
the Constitution itself permits conviction for treason only where there is a “[c]onfession in open
[c]ourt,” or “testimony of two [w]itnesses to the same overt [a]ct”175—an action committed in
furtherance of the treason.176 Second, the Supreme Court has held that treason requires proof that
the defendant “intend[ed] to betray his country.”177 Third, treason may only be committed by
those who owe allegiance to the United States—such as citizens or some temporary residents178—
and who breach that allegiance.179 Furthermore, the concept of “levying war” is a “meticulously
exclusive” phrase,180 which the Supreme Court has held applies only to conduct involving “an
actual assemblage of men for the purpose of executing a treasonable design.”181 It is unclear from
the limited case law exactly what conduct would count within that definition, and the Supreme
Court has cautioned that the “crime of treason should not be extended by construction to doubtful
cases.”182 Conduct that falls outside the narrow definition of treason may still be subject to
prosecution under other laws concerning crimes against the government—such as seditious
conspiracy discussed below.183
Insurrection: 18 U.S.C. § 2383
The federal insurrection statute authorizes fines and up to ten years of imprisonment for anyone
who “incites, sets on foot, assists, or engages in any rebellion or insurrection against the authority
of the United States or the laws thereof, or gives aid or comfort thereto.”184 The statute also bars
anyone convicted of violating that provision from “holding any office under the United States.”185
The exact scope of the insurrection statute is unclear, in part because it does not define
“rebellion” or “insurrection.”186 In addition, there is little interpretive case law, because
prosecutions under the insurrection statute are rare.187

174 J. Richard Broughton, Constitutional Discourse and the Rhetoric of Treason, 47 HASTINGS CONST. L.Q. 303, 311
(2020) (“There has been no American treason conviction in well over a half century.”); Paul T. Crane, Did the Court
Kill the Treason Charge?: Reassessing Cramer v. United States and Its Significance, 36 FLA. ST. U. L. REV. 635, 639
(2009) (“However, after 1954 not a single American was charged with treason until . . . 2006.”).
175 U.S. CONST. art. III, § 3, cl. 1.
176 See Haupt v. United States, 330 U.S. 631, 635 (1947) (contrasting defendant’s overt acts that furthered the treason
with a past case where proof of overt acts were insufficient because there was no testimony of the “treasonable
character” of those overt acts).
177 Cramer v. United States, 325 U.S. 1, 31 (1945).
178 Carlisle v. United States, 83 U.S. 147, 154-55 (1872).
179 See United States v. Rahman, 189 F.3d 88, 113 (2d Cir. 1999) (“Moreover, any acceptable recitation of the elements
of treason must include the breach of allegiance.”).
180 Stephan v. United States, 133 F.2d 87, 90 (6th Cir. 1943).
181 Ex parte Bollman, 8 U.S. 75, 127 (1807).
182 Id.
183 See generally Memorandum From Deputy Attorney General Jeffrey A. Rosen For All United States Attorneys –
Charging in connection with violent rioting, including 18 U.S.C. § 2384 (Sep. 17, 2020),
https://www.justice.gov/archives/opa/page/file/1317916/download [hereinafter Rosen Memorandum] (describing
potential applicability of seditious conspiracy charges); see also Crane, supra note 174, at 639 (linking the limited
treason prosecutions to the availability of other statutory charges).
184 18 U.S.C. § 2383.
185 Id.
186 Id.
187 Erin Creegan, National Security Crime, 3 HARV. NAT’L SEC. J. 373, 381 (2012).
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Seditious Conspiracy: 18 U.S.C. § 2384
Section 2384 of Title 18 of the U.S. Code provides:
If two or more persons in any State or Territory, or in any place subject to the jurisdiction
of the United States, conspire to overthrow, put down, or to destroy by force the
Government of the United States, or to levy war against them, or to oppose by force the
authority thereof, or by force to prevent, hinder, or delay the execution of any law of the
United States, or by force to seize, take, or possess any property of the United States
contrary to the authority thereof, they shall each be fined under this title or imprisoned not
more than twenty years, or both.188
In a 2020 memo to U.S. Attorneys (hereinafter the “Rosen Memo”), then-Deputy Attorney
General Jeffrey A. Rosen noted that the statute “does not require proof of a plot to overthrow the
U.S. Government, despite what the name might suggest.”189 Rather, the statute applies to any
conspiracy—i.e., an agreement with the requisite intent190—with the object of using force to (1)
overthrow, put down, or destroy the U.S. government, (2) oppose the authority of the United
States, (3) prevent, hinder, or delay the execution of any law of the United States, or (4) seize,
take, or possess any property of the United States contrary to its authority, among other things.191
Though recent case law interpreting these phrases is limited, some authority indicates the types of
conduct that might fall within the statute’s scope.192 For instance, the Rosen Memo specifically
noted that charges under Section 2384 could be “potentially available” “where a group has
conspired to take a federal courthouse or other federal property by force,” presumably under the
statutory prong proscribing forcibly seizing, taking, or possessing any property of the United
States contrary to its authority.193 Additionally, in an early twentieth century case, one federal
court of appeals indicated that the prong addressing prevention, hindrance, or delay of the
execution of federal law prohibits a conspiracy to use force “against some person who has
authority to execute and who is immediately engaged in executing a law of the United States.”194
The seditious conspiracy statute has been used in recent decades in circumstances such as plots to
bomb government buildings.195
With regard to the seditious conspiracy statute’s “oppose by force” prong, a district court
recognized that it implies “force against the government as a government.”196 The district judge
explained that “the law is clear that seditious conspiracy requires an agreement to oppose by force
the authority of the United States itself.”197 The judge further explained that “offensive speech
and a conspiracy to do something other than forcibly resist a positive show of authority” by the
government “is not enough to sustain a charge of seditious conspiracy.”198 As such, whether

188 18 U.S.C. § 2384.
189 See Rosen Memorandum, supra note 183.
190 John Alan Cohan, Seditious Conspiracy, the Smith Act, and Prosecution for Religious Speech Advocating the
Violent Overthrow of Government, 17 ST. JOHN'S J. LEGAL COMMENT. 199, 210 (2003).
191 18 U.S.C. § 2384.
192 See Cohan, supra note 190, at 206 (describing seditious conspiracy statute as “rarely used”).
193 Rosen Memorandum, supra note 183.
194 Haywood v. United States, 268 F. 795, 800 (7th Cir. 1920).
195 E.g., United States v. Rodriguez, 803 F.2d 318, 319 (7th Cir. 1986).
196 United States v. Stone, No. 10-20123, 2012 WL 1034937, at *4 (E.D. Mich. Mar. 27, 2012) (quoting Baldwin v.
Franks, 120 U.S. 678, 693 (1887)).
197 Id.
198 Id. at *5.
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charges would be warranted under the seditious conspiracy statute in connection with acts of
domestic terrorism could ultimately depend not only on whether the conduct related to an
agreement between two or more persons to take forcible action against the government, but also
on whether (depending on the statutory prong at issue) the object of the agreement was actually in
opposition to a positive assertion of government authority.199 Seditious conspiracy charges are
reportedly under consideration by DOJ in connection with the events of January 6, 2021 at the
U.S. Capitol.200
Crimes against Persons
Domestic terrorism, by statutory definition, involves acts “dangerous to human life.”201
Regardless of its specific purpose then, conduct consistent with the statutory definition of
domestic terrorism may violate a variety of federal statutes prohibiting crimes against persons.202
For example, federal criminal statutes prohibit the kidnapping, assault, murder, or assassination of
Members of Congress, Members-of-Congress Elect, Supreme Court Justices or nominees, various
Cabinet members,203 the President, Presidential Staff, the Vice President, the President-elect and
Vice President-elect,204 and family members of certain United States officials, judges or federal
law enforcement officers.205 Another federal statute criminalizes, among other things,
conspiracies to use force to injure federal officers or officials.206 Other federal criminal statutes
prohibit assault and other violent conduct where the victim is within a certain type of special
jurisdiction of the United States.207 Although a comprehensive review of these and other federal
laws prohibiting crimes against persons is beyond the scope of this report, this section provides an
overview of several key statutes prohibiting crimes against persons, which may be of particular
relevance in the context of domestic terrorism.

199 Another statute separately proscribes knowingly or willfully advocating, abetting, advising or teaching “the duty,
necessity, desirability, or propriety of overthrowing or destroying” the federal or a state or local government “by force
or violence” or by assassination, as well as organization of or affiliation with groups that do the same and distribution
of related printed matter. 18 U.S.C. § 2385. Depending on the circumstances, some conduct to which Section 2384 is
relevant might also be considered under Section 2385.
200 See, supra note 168 and accompanying text; but see Mark Hosenball, No seditious conspiracy charges emerge in
U.S. Capitol riots cases, REUTERS (June 3, 2021), https://www.reuters.com/legal/government/no-seditious-conspiracy-
charges-emerge-us-capitol-riots-cases-2021-06-03/ (“A law enforcement official, who asked for anonymity to discuss
debates among prosecutors, said there had been little recent discussion among key officials regarding seditious
conspiracy charges.”).
201 18 U.S.C. § 2331(5).
202 Infra, § “Hate Crimes.”
203 18 U.S.C. § 351. This statute is a predicate offense listed in 18 U.S.C. § 2339A, discussed above. Supra, § “Material
Support to Terrorists Under 18 U.S.C. § 2339A.”
204 Id. § 1751. This statute is a predicate offense listed in 18 U.S.C. § 2339A, discussed above.
205 Id. § 115.
206 Id. § 372; accord United States v. Rakes, 510 F.3d 1280, 1288 (10th Cir. 2007) (listing elements under § 372 as
requiring “(1) two or more persons to conspire (2) to prevent any person from discharging the duties of their office
under the United States (3) by force, intimidation, or threat.”).
207 See, e.g., 49 U.S.C. § 46504 (prohibiting assaulting or intimidating a “flight crew member or flight attendant of the
aircraft” “on an aircraft in the special aircraft jurisdiction of the United States,” if it “interferes with the performance of
the duties of the member or flight attendant” (§ 46504 is a predicate offense for 18 U.S.C. § 2339A discussed above));
18 U.S.C. § 1111 (prohibiting the “unlawful killing of a human being” when committed in the special territorial
jurisdiction of the United States, such as various federal buildings and lands); id. § 113 (criminalizing assaults
committed “within the special maritime and territorial jurisdiction of the United States”).
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Assaulting, Resisting, or Impeding Federal Officers or Employees: 18 U.S.C. § 111
Among other things, Section 111 of Title 18 of the U.S. Code authorizes various prison terms208
for forcibly assaulting, resisting, opposing, impeding, intimidating, or interfering with certain
federal officers or employees.209 DOJ has charged dozens of individuals under Section 111 in
connection to the events of January 6, 2021 at the Capitol,210 including individuals who allegedly
struck law enforcement officers211 or sprayed them with chemical agents,212 among others.213
On its face, the statute appears to cover not only forcible assault—i.e., “an attempt or threat to
injure”214—but broader categories of conduct such as forcibly opposing or impeding a federal
officer.215 However, regardless of the statutory term at issue, the conduct proscribed by Section
111 must be forcible, which does not require physical contact but, in one formulation, requires at
least some “display of physical aggression toward the officer.”216 Federal courts disagree on
whether Section 111 also requires, at a minimum, simple assault—meaning an attempt or threat to
injure that does not involve actual physical contact, a weapon, bodily injury, or intent to commit
certain felonies.217 Section 111 protects “any officer or employee of the United States or of any
agency in any branch of the United States Government (including any member of the uniformed
services)” and protects such individuals from being harmed while “engaged in or on account of”
the person’s “performance of official duties.”218 The statute may also protect state and local
officers acting in cooperation with, and under the control of, federal officers,219 and private
citizens when they are assisting federal employees in their official duties.220 Determining whether
an officer or employee is “engaged in . . . performance of official duties” calls for a fact-specific
analysis, but the officer or employee does not necessarily have to be “on duty” to meet the
standard so long as he or she is carrying out a federal function.221 Importantly, Section 111 also

208 Acts under the statute that qualify as only “simple assault” are punishable by up to one year in prison, while acts that
“involve physical contact with the victim of that assault or the intent to commit another felony” are punishable by
imprisonment for up to eight years. Id. § 111(a). Use of a deadly or dangerous weapon or infliction of bodily injury
enhances the applicable penalty to up to twenty years in prison. Id. § 111(b).
209 Id. § 111(a)(1).
210 Capitol Breach Cases, supra note 155.
211 E.g., Criminal Complaint, United States v. Blair, No. 1:21-mj-00211 (D.D.C. 2021).
212 E.g., Affidavit in Support of Criminal Complaint and Arrest Warrant, United States v. Nichols, No. 21-MJ-102; No.
21-MJ-103 (D.D.C. 2021).
213 For a synopsis of charges filed to date, see generally Capitol Breach Cases, supra note 155.
214 United States v. Wolfname, 835 F.3d 1214, 1217 (10th Cir. 2016).
215 18 U.S.C. § 111(a)(1).
216 United States v. Taylor, 848 F.3d 476, 493 (1st Cir. 2017).
217 Compare Wolfname, 835 F.3d at 1218 (“Because a § 111(a)(1) conviction for resisting, opposing, impeding,
intimidating, or interfering must fall into one of these two categories, a conviction for any of these acts necessarily
involves—at a minimum—simple assault.”) and United States v. Chapman, 528 F.3d 1215, 1219 (9th Cir. 2008)
(similar), with United States v. Gagnon, 553 F.3d 1021, 1026 (6th Cir. 2009) (concluding a violation of Section 111
does not necessarily require an assault).
218 18 U.S.C. § 111.
219 United States v. Hooker, 997 F.2d 67, 74 (5th Cir. 1993); United States v. Burns, 725 F. Supp. 116, 130 (N.D.N.Y.
1989).
220 See, e.g., United States v. Holder, 256 F.3d 959, 966 (10th Cir. 2001) (affirming conviction under § 111(a) where
defendant shot a private citizen assisting a United States Department of Agriculture employee in building a fence to
comply with a wetlands easement).
221 See United States v. Perea, 818 F. Supp. 2d 1293, 1303 (D.N.M. 2010) (collecting cases where victim was not
necessarily on-duty).
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requires that a person intend to engage in the proscribed conduct but does not require knowledge
that the person subjected to the conduct is a federal officer or employee.222
Protection of Officers and Employees of the United States: 18 U.S.C. § 1114
The same government officers and officials protected by Section 111 also fall within the scope of
Section 1114 of Title 18 of the U.S. Code, which criminalizes the attempted or actual killing of
such individuals.223 The maximum penalties authorized by the statute vary based on the
circumstances and defendant’s state of mind.224 For example, a minimum sentence of life
imprisonment is mandated where a federal officer or official is murdered by “poison, lying in
wait, or any other kind of willful, deliberate, malicious, and premeditated killing,” or in the
commission of “kidnapping, treason, espionage” or “sabotage,” among other things.225 Murder,
for Section 1114 purposes is “the unlawful killing of a human being with malice
aforethought”226—a notoriously confusing concept,227 which generally requires either intent to
inflict “serious bodily injury” or kill, or an “extreme recklessness and wanton disregard for
human life.”228
Kidnapping: 18 U.S.C. § 1201
Section 1201 of Title 18 of the U.S. Code prohibits kidnapping and related behavior in certain
contexts.229 The statute departs from the original common law definition of kidnapping, which

222 United States v. Feola, 420 U.S. 671, 684 (1975).
223 18 U.S.C. § 1114. Section 1114 is a predicate offense for 18 U.S.C. § 2339A discussed above.
224 Id.; id. §§ 1112, 1113.
225 Id. § 1111
226 Id.
227 See generally United States v. Delaney, 717 F.3d 553, 555-59 (7th Cir. 2013) (describing malice aforethought and
related terms and surveying the confusion often accompanying such concepts); Malice Aforethought, BLACK’S LAW
DICTIONARY (11th ed. 2019) (defining malice aforethought as “encompassing any one of the following: (1) the intent to
kill, (2) the intent to inflict grievous bodily harm, (3) extremely reckless indifference to the value of human life (the so-
called ‘abandoned and malignant heart’), or (4) the intent to commit a dangerous felony (which leads to culpability
under the felony-murder rule)”).
228 Frascarelli v. United States Parole Comm’n, 857 F.3d 701, 705-06 (5th Cir. 2017) (quoting United States v.
Browner, 889 F.2d 549, 551-52 (5th Cir. 1989)); accord United States v. Slager, 912 F.3d 224, 235-36 (4th Cir.
2019), cert. denied, 139 S. Ct. 2679 (2019) (“Malice aforethought may be established by evidence of conduct which is
reckless and wanton and a gross deviation from a reasonable standard of care, of such a nature that a [factfinder] is
warranted in inferring that [the] defendant was aware of a serious risk of death or serious bodily harm.” (quoting United
States v. Ashford, 718 F.3d 377, 384 (4th Cir. 2013)).
229 18 U.S.C. § 1201. Another similar statute is the federal hostage taking statute—18 U.S.C. § 1203. See United States
v. Carrion-Caliz, 944 F.2d 220, 223 (5th Cir. 1991) (observing that “the federal kidnapping statute and the Hostage
Taking Act are quite similar” with respect to their language and the conduct they prohibit). Under § 1203 it is a crime
to seize or detain an individual and threaten to kill, injure, or continue the detention of that individual in order to
compel the government or another individual to engage in, or refrain from, some action. 18 U.S.C. § 1203. In contrast
to § 1201, which has limited “application to acts that occur beyond the borders of the United States,” § 1203 “was
adopted specifically ‘to extend jurisdiction over extraterritorial crimes.’” Carrion-Caliz, 944 F.2d at 224 (quoting
United States v. Yunis, 681 F.Supp. 896, 904 (D.D.C.1988)). Consistent with its focus on extraterritorial crime, § 1203
ordinarily does not apply to conduct committed inside the United States. 18 U.S.C. § 1203(b)(2). Thus its application to
domestic terrorism may be limited, although there are statutory exceptions that could make the statute relevant in
certain circumstances—such as where “the governmental organization sought to be compelled is the Government of the
United States.” Id. Section 1203 is a predicate offense for 18 U.S.C. § 2339A discussed above. Additional federal
statutes prohibit certain kidnapping threats. See infra, § “Crimes Involving Threats.”
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narrowly referred to “tak[ing] and carry[ing] a person by force and against his will.”230 In
contrast, Section 1201 encompasses a much broader array of conduct where a person is taken or
confined without consent.231 Under Section 1201(a) the statute applies where a defendant has
“unlawfully seize[d], confine[d], inveigle[d], decoy[ed], kidnap[ped], abduct[ed], or carri[ed]
away” a victim.232 The Supreme Court has observed that this “[c]omprehensive language was
used to cover every possible variety of kidnapping.”233 Thus, unlike kidnapping under the
common law, Section 1201 does not require “asportation”—the carrying away of the victim.234
Instead, restraining the victim’s freedom, for example by seizure or confinement, may be
sufficient.235 In another divergence from common law kidnapping, a defendant may violate
Section 1201(a) even if he does not use force—rather, tactics such as placing the victim in fear,236
or using “false representations” or “promises” may also run afoul of the statute.237
Despite this breadth, there are several limits on the applicability of Section 1201(a). First, the
defendant must “hold[] for ransom or reward or otherwise any person,” which according to the
Supreme Court, “implies an unlawful physical or mental restraint for an appreciable period
against the person’s will and with a willful intent so to confine the victim.”238 The “‘holding’
requirement is an essential element of kidnapping and must be established in every case,”239 but
“it has received surprisingly little attention in the case law.”240 One federal appellate court has
suggested that holding requires more than fleeting conduct such as “momentary detention in the
course of a holdup.”241 Courts also have interpreted the requirement that the victim be held for a
prohibited purpose—namely “ransom or reward or otherwise”—broadly.242 As one federal
appellate court explained, a defendant need only hold a victim “for any reason which would in
any way be of benefit” to the defendant.243 Second, Section 1201(a) requires that the conduct
implicates one of several jurisdictional nexuses, which may be satisfied where, for example, the
defendant travels in interstate commerce in furtherance of the offense or where the victim is a
federal official or employee.244 Third, courts have interpreted Section 1201(a) to impose intent
requirements on the part of the defendant.245

230 United States v. Young, 512 F.2d 321, 323 (4th Cir. 1975).
231 Id.
232 18 U.S.C. § 1201(a).
233 Chatwin v. United States, 326 U.S. 455, 463 (1946).
234 United States v. Etsitty, 130 F.3d 420, 426 (9th Cir. 1997), opinion amended on denial of reh'g, 140 F.3d 1274 (9th
Cir. 1998).
235 18 U.S.C. § 1201(a).
236 Chatwin, 326 U.S. at 460; accord WAYNE R. LAFAVE, SUBSTANTIVE CRIMINAL LAW § 18:2(a) (3d ed. 2019).
237 United States v. Hoog, 504 F.2d 45, 51 (8th Cir. 1974).
238 Chatwin, 326 U.S. at 460.
239 United States v. Larsen, 615 F.3d 780, 787 (7th Cir. 2010).
240 LaFave, supra note 236, § 18.2(a).
241 United States v. DeLaMotte, 434 F.2d 289, 292-93 (2d Cir. 1970).
242 United States v. Small, No. 20-5117, 2021 WL 486879, at *3 (6th Cir. Feb. 10, 2021).
243 Id.
244 18 U.S.C. § 1201.
245 See United States v. Miers, 686 F. App’x 838, 843 (11th Cir. 2017) (requiring that government must prove that
defendant acted knowingly and willfully to “support a conviction under 18 U.S.C. § 1201(a)”); United States v.
Ouedraogo, 531 F. App’x 731, 744 (6th Cir. 2013) (similar); United States v. Garza-Robles, 627 F.3d 161, 166 (5th
Cir. 2010) (similar); United States v. Eng., No. 18 CR. 492 (PGG), 2020 WL 7773606, at *15 (S.D.N.Y. Dec. 30,
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Violations of Section 1201(a) may ordinarily be punished by up to life imprisonment.246 For
violations resulting in death, however, Section 1201(a) imposes a mandatory minimum penalty of
life imprisonment, and authorizes the death penalty.247 A separate subsection—Section 1201(c)—
also authorizes up to life imprisonment for conspiracies that violate Section 1201.248 Prosecutions
under Section 1201 have included, among others,249 that of six defendants in connection with the
2020 plot to kidnap Michigan Governor Gretchen Whitmer as part of a purported plan to
overthrow the government.250
Crimes Involving Infrastructure or Federal Property
Depending on where they occur and what they target, acts of domestic terrorism could
conceivably run afoul of various federal criminal statutes that prohibit illicit conduct with respect
to certain infrastructure or property.251 For example, acts of domestic terrorism that occur on, or
otherwise implicate, federal property could violate a number of federal criminal statutes
protecting federal government property from destructive or violent behavior, among other things.
A detailed analysis of these statutes is available in other CRS products,252 but statutes that could
be relevant to acts of domestic terrorism involving federal property include:
 Vandalism of Government Property, 18 U.S.C. § 1361: Authorizes various fines
and prison terms for willful injury of federal property.253
 Restricted Buildings or Grounds, 18 U.S.C. § 1752: Imposes a range of criminal
penalties254 for certain conduct at “restricted building or grounds,” which are
defined to include, among others, locations where a “person protected by the

2020) (similar); United States v. Eason, No. 15-20015, 2016 WL 3545467, at *1 (C.D. Ill. June 22, 2016), aff'd, 854
F.3d 922 (7th Cir. 2017) (similar).
246 18 U.S.C. § 1201(a).
247 Id.
248 Id. Conspiracy is discussed in greater detail, infra, § “Conspiracy.”
249 See, e.g., United States v. Medina, No. 2:20-CR-119, 2021 WL 1152708, at *1 (S.D. Ohio Mar. 26, 2021)
(providing background of § 1201 prosecution connected to a “days-long hostage situation”).
250 Press Release, U.S. Dep’t of Justice, Six Arrested on Federal Charge of Conspiracy to Kidnap the Governor of
Michigan (Oct. 8, 2020), https://www.justice.gov/opa/pr/six-arrested-federal-charge-conspiracy-kidnap-governor-
michigan; Criminal Complaint, United States v. Fox, No. 1:21-mj-416 (W.D. Mich. 2020). Several defendants in the
matter have also been charged with other offenses such as “conspiracy to use a weapon of mass destruction and . . .
federal firearms violations.” Press Release, U.S. Dep’t of Justice, Federal Grand Jury Returns a Superseding Indictment
Adding New Charges in the Conspiracy to Kidnap Michigan Governor Gretchen Whitmer (Apr. 28, 2021),
https://www.justice.gov/opa/pr/federal-grand-jury-returns-superseding-indictment-adding-new-charges-conspiracy-
kidnap.
251 See, e.g., 18 U.S.C. § 43(a), (d)(1) (prohibiting certain damage or threats directed at animal enterprises such as zoos,
circuses, aquariums, agricultural fairs, animal breeders, and academic or commercial entities engaged in animal
research or testing (among others)); id. § 1369 (prohibiting, among other things, willful injury to, or destruction of,
veteran’s memorials “located on property owned by, or under the jurisdiction of, the Federal Government”); id. § 1855
(criminalizing, among other things, willfully setting fires to “timber, underbrush, or grass” without authority on certain
federal lands); id. § 2152 (proscribing certain acts of trespass, injury, or destruction with respect to the “works or
property or material of any submarine mine or torpedo or fortification or harbor defense system owned . . . by the
United States”).
252 See generally CRS Legal Sidebar LSB10493, Federal Criminal Laws Applicable to Rioting, Property Destruction,
and Related Conduct, by Peter G. Berris and Michael A. Foster; CRS Legal Sidebar LSB10564, Federal Criminal
Law: January 6, 2021, Unrest at the Capitol, by Michael A. Foster and Peter G. Berris.
253 18 U.S.C. § 1361. Section 1361 is a predicate offense for 18 U.S.C. § 2339A discussed above.
254 Id. § 1752(b).
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Secret Service,” such as the Vice President, “is or will be temporarily visiting.”255
Conduct prohibited at restricted buildings or grounds includes: (1) knowingly
entering or remaining without lawful authority; (2) knowingly engaging in
disruptive conduct, or impeding ingress or egress, “with intent to impede or
disrupt the orderly conduct of Government Business or official functions;” and
(3) knowingly engaging in “any act of physical violence against any person or
property.”256
 Unlawful Activities at United States Capitol Buildings and Grounds, 40 U.S.C.
§ 5104: Authorizes various criminal penalties257 for a range of conduct and
activities on Capitol grounds or in Capitol buildings, specifically defined by a
separate statute to include certain streets, roadways, and other areas surrounding
the Capitol itself. Capitol buildings are defined to include the U.S. Capitol
building and House and Senate office buildings, among other things.258 In
general, Section 5104 prohibits:
 knowingly, with force and violence, entering or remaining on the floor of
either house of Congress;
 willfully and knowingly obstructing or impeding passage through or within
the Capitol grounds or buildings;
 willfully and knowingly engaging in an act of physical violence (defined as
an act involving assault, other infliction or threat of infliction of death or
bodily harm to an individual, or damage or destruction of real or personal
property) on Capitol grounds or in Capitol buildings;
 and, except as authorized by Capitol Police Board regulations, carrying or
having readily accessible a firearm, a dangerous weapon (including a dagger
or knife with a blade over three inches), an explosive, or an incendiary
device, or using or discharging any of the preceding items.259
These statutes have been among the charges filed by DOJ in a number of cases arising from the
events of January 6, 2021 at the U.S. Capitol, which illustrates their potential application to
violent and destructive conduct targeting or occurring on federal property.260
Depending on the circumstances, acts of domestic terrorism could also implicate a variety of
federal statutes that prohibit violent or destructive conduct targeting or involving infrastructure.
For instance, a number of federal criminal statutes extend various protections to aircraft,261

255 Id. § 1752(a), (c)(1).
256 Id. § 1752(a)(1)-(5).
257 40 U.S.C. §§ 5109(a)-(b).
258 Id. § 5102.
259 Id. § 5104. A separate statute also prohibits, with exceptions, knowing possession of a firearm or other dangerous
weapon in a “federal facility,” the definition of which would appear to include the Capitol buildings because they are
“owned or leased by the federal government” and have federal employees regularly present for the purpose of
performing official duties. 18 U.S.C. § 930.
260 Capitol Breach Cases, supra note 155.
261 See, e.g., 18 U.S.C. § 32 (criminalizing various destructive conduct directed towards aircraft or aircraft facilities
(§ 32 is a predicate offense for 18 U.S.C. § 2339A discussed above)); 49 U.S.C. § 46502 (imposing criminal penalties
for aircraft piracy (§ 46502 is a predicate offense for 18 U.S.C. § 2339A discussed above)); id. § 46505 (making it a
crime to place, or attempt to place, an explosive or incendiary device on an aircraft, or use a dangerous weapon during
flight (§ 46505 is a predicate offense for 18 U.S.C. § 2339A discussed above)).
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international airports,262 railroads and mass transportation systems,263 energy facilities,264
interstate gas pipelines and facilities,265 and communications lines or systems.266
Hate Crimes
Depending on a defendant’s motives or objectives, illicit conduct directed at persons or property
may sometimes be a hate crime—defined by the FBI as a “criminal offense against a person or
property motivated in whole or in part by an offender’s bias against a race, religion, disability,
sexual orientation, ethnicity, gender, or gender identity.”267 As discussed in another CRS product,
the line between hate crimes and domestic terrorism can be “blurry.”268 Some cases may be
“investigated as both a hate crime and an act of domestic terrorism,” and DOJ has sometimes
used both designations in connection with a single incident.269 For example, DOJ pursued federal
hate crime charges against an “Ohio man who drove his car into a crowd of counter-protestors” at
the 2017 “Unite the Right Rally” in Charlottesville, Virginia.270 In the press release announcing a
guilty plea in that case, DOJ described the conduct as both a hate crime and domestic terrorism.271
Similarly, a defendant who plotted to blow up a Colorado synagogue pleaded guilty to hate crime
charges, and DOJ referred to his conduct as domestic terrorism in a press release.272
Given this conceptual overlap, federal hate crime statutes may be particularly relevant to the
context of domestic terrorism. This section provides a brief overview of two such federal hate
crime statutes: (1) Section 247 of Title 18 of the U.S. Code (prohibiting certain destruction of
religious property or interference with the free exercise of religion) and (2) the Matthew Shepard
and James Byrd Jr. Hate Crimes Prevention Act of 2009 (HCPA), 18 U.S.C. § 249. Depending on
the circumstances, a number of other federal statutes could also be applicable in the hate crime
context, such as those prohibiting conspiracies to interfere with civil rights,273 or criminalizing
violent interference with certain federally protected rights.274 A discussion of these additional
statutes may be found in other CRS products.275

262 See, e.g., 18 U.S.C. § 37 (criminalizing certain violence and destructive behavior at international airports (§ 37 is a
predicate offense for 18 U.S.C. § 2339A discussed above)).
263 See, e.g., id. § 1992 (prohibiting certain violent or destructive conduct directed towards railroads and other mass
transportation systems (§ 1992, which uses the phrase “terrorist attacks” in its title, is a predicate offense for 18 U.S.C.
§ 2339A discussed above)).
264 E.g., id. § 1366.
265 E.g., 49 U.S.C. § 60123(b). Section 60123(b) is a predicate offense for 18 U.S.C. § 2339A discussed above.
266 E.g., 18 U.S.C. § 1362. Section 1362 is a predicate offense for 18 U.S.C. § 2339A discussed above.
267 Hate Crimes, FBI, https://www.fbi.gov/investigate/civil-rights/hate-crimes (last visited May 20, 2020).
268Sacco, supra note 4.
269 Id.
270 Press Release, U.S. Dep’t of Justice, Ohio Man Sentenced to Life in Prison for Federal Hate Crimes Related to
August 2017 Car Attack at Rally in Charlottesville, Virginia (June 28, 2019), https://www.justice.gov/opa/pr/ohio-man-
sentenced-life-prison-federal-hate-crimes-related-august-2017-car-attack-rally.
271 Id.
272 Press Release, U.S. Dep’t of Justice, Southern Colorado Man Sentenced to More Than 19 Years for Plotting to Blow
Up Synagogue (Feb. 26, 2021), https://www.justice.gov/opa/pr/southern-colorado-man-sentenced-more-19-years-
plotting-blow-synagogue.
273 18 U.S.C. § 241.
274 Id. § 245; 42 U.S.C. § 3631.
275 CRS In Focus IF11312, Department of Justice’s Role in Investigating and Prosecuting Hate Crimes, by Nathan
James.
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Damage to Religious Property or Obstruction of Free Exercise: 18 U.S.C. § 247
Section 247 essentially prohibits two categories of conduct. The first category includes
intentionally defacing, damaging, or destroying “religious real property,”276 defined as “any
church, synagogue, mosque, religious cemetery, or other religious real property, including fixtures
or religious objects contained within a place of religious worship, or real property owned or
leased by a nonprofit, religiously affiliated organization.”277 According to legislative history,
Congress meant for this definition to include not only buildings and grounds, but also objects
such as “torahs inside a synagogue.”278 A range of destructive conduct targeting religious real
property may fall within this category, including bombings,279 vandalism,280 and intentional
fires.281 However, Section 247 only applies to destructive conduct committed because of the
“religious character of that property” (assuming the conduct is “in or affects interstate or foreign
commerce”)282 or because of “the race, color, or ethnic characteristics of any individual associated
with that religious property.”283 In addition, the conduct must be intentional, a term undefined in
Section 247.284 In general “one intends certain consequences when he desires that his acts cause
those consequences or knows that those consequences are substantially certain to result from his
acts.”285
The second category of conduct that Section 247 criminalizes also includes actual or threatened
force—specifically when used to obstruct an individual’s enjoyment of free exercise of religious
beliefs.286 Drawing from First Amendment precedent, at least one federal court of appeals has
concluded that Section 247’s protection of free exercise of religious beliefs broadly
“encompass[es] both . . . active practice” as well as “passive disassociation,” such as the choice
“to be free from the practice of religion altogether.”287 The court thus affirmed the Section 247
convictions of several defendants who had killed three former members of their religious sect
because the former members had “chosen to disassociate themselves from the church’s teachings

276 In general, real property includes “[l]and and anything growing on, attached to, or erected on it, excluding anything
that may be severed without injury to the land.” Property, BLACK’S LAW DICTIONARY (11th ed. 2019).
277 18 U.S.C. § 247(f).
278 142 CONG. REC. 17139, 17212 (1996) (joint statement of Sen. Lauch Faircloth, Sen. Edward Kennedy, Rep. John
Conyers, and Rep. Henry Hyde).
279 E.g., United States v. Hari, No. 18CR015001DWFHB, 2019 WL 7838282, at *2 (D. Minn. Sept. 17, 2019), report
and recommendation adopted, No. CR181501DWFHB, 2019 WL 6975425 (D. Minn. Dec. 20, 2019) (describing § 247
charges against defendant that bombed Islamic Center).
280 E.g., Press Release, U.S. Dep’t of Justice, Man Sentenced in Connection with Arson at Planned Parenthood and
Vandalism of Mosque in Madera, California (Jan. 9, 2012), https://www.justice.gov/opa/pr/man-sentenced-connection-
arson-planned-parenthood-and-vandalism-mosque-madera-california (describing charge for destruction of religious
property against individual who threw brick at mosque).
281 E.g., United States v. Perez, No. 18-40707, 2020 WL 7786934, at *1 (5th Cir. Dec. 30, 2020) (describing § 247
charges against defendant that burned down Islamic Center); Press Release, U.S. Dep’t of Justice, Louisiana Man
Pleads Guilty to Burning Three Baptist Churches in St. Landry Parish (Feb. 10, 2020),
https://www.justice.gov/opa/pr/louisiana-man-pleads-guilty-burning-three-baptist-churches-st-landry-parish
(summarizing § 247 charge against defendant who burned churches).
282 18 U.S.C. §§ 247(a)(1), 247(b) (footnote added).
283 Id. § 247(c).
284 Id. § 247.
285 Tison v. Arizona, 481 U.S. 137, 150 (1987) (quoting W. LAFAVE & A. SCOTT, CRIMINAL LAW, § 28, p. 196 (1972)).
286 18 U.S.C. § 247(a)(2).
287 United States v. Barlow, 41 F.3d 935, 936, 943 (5th Cir. 1994) (emphasis omitted).
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and its fellowship.”288 That court also more broadly concluded that Congress intended Section
247(a)(2) to cover “the entire panoply of activities” protected under the U.S. Constitution’s Free
Exercise Clause.289
To qualify as a Section 247 violation, obstruction of free exercise of religion must affect interstate
commerce.290 That could occur, for example, where a suspect crosses state borders while
committing an offense or uses interstate highways.291 As with other conduct prohibited in Section
247, a defendant’s interference with free exercise of religion must be intentional.292
Ordinarily, Section 247 violations may be punished by a maximum penalty of a $100,000 fine, a
year of imprisonment, or both.293 However, the statute authorizes more severe punishments in a
number of circumstances, including the death penalty.294 Since its enactment, Section 247 has
been used to prosecute a range of conduct motivated by religious bias, including the plotted arson
of a mosque,295 the revenge killing of former members of a religious group who sought to
dissociate from that religion,296 and a shooting at a synagogue.297
Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act of 2009: 18
U.S.C. § 249
Generally, Section 249 makes it a crime to “willfully cause[] bodily injury to any person or,
through the use of . . . a dangerous weapon,” attempt to “cause bodily injury to any person” due
to certain biases against the victim. Thus, the statute’s scope depends in part on the meaning of
both “willfully” and “bodily injury.”298 According to at least one court, conduct is willful in the
context of Section 249 when it occurs “voluntarily and intentionally and with the specific intent
to do something which the law forbids. . . that is to say, with bad purpose either to disobey or
disregard the law.”299 “Bodily injury,” meanwhile, includes only “an actual physical injury”300
such as cuts, abrasions, bruises, burns, disfigurement, physical pain, illness, or an “impairment of
the function of a bodily member, organ, or mental faculty.”301 It does not include emotional or
psychological harm.302 However, bodily injury need not actually result so long as the defendant

288 Id. at 936-37. Another victim was the daughter of a former member who had witnessed the crime. Id.
289 Id. at 943. For a recent examination of the scope of constitutional protections for the free exercise of religion, see
generally CRS Legal Sidebar LSB10450, UPDATE: Banning Religious Assemblies to Stop the Spread of COVID-19,
by Valerie C. Brannon.
290 18 U.S.C. § 247(b).
291 United States v. Ballinger, 395 F.3d 1218, 1226-27 (11th Cir. 2005).
292 18 U.S.C. § 247(a)(2).
293 18 U.S.C. §§ 247; 3571.
294 Id. § 247.
295 United States v. Doggart, 947 F.3d 879, 881 (6th Cir. 2020).
296 United States v. Barlow, 41 F.3d 935, 943 (5th Cir. 1994).
297 Complaint, United States v. Earnest, No. 19MJ1900 (S.D. Cal. filed May 9, 2009), available at
https://www.justice.gov/opa/press-release/file/1161421/download.
298 18 U.S.C. § 249(a)(1).
299 Glenn v. Holder, 690 F.3d 417, 422-23 (6th Cir. 2012) (quoting United States v. Brown, 151 F.3d 476, 486 (6th Cir.
1998)) (internal quotation marks omitted).
300 United States v. Jenkins, 909 F. Supp. 2d 758, 777 (E.D. Ky. 2012).
301 18 U.S.C. §§ 249(c)(1), 1365(h)(4).
302 Id. § 249(c)(1) (defining “bodily injury” to exclude “solely emotional or psychological harm”).
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attempted to cause bodily injury through use of a weapon, firearm,303 incendiaries, explosives,304
or fire.305
As noted, in order for conduct to violate Section 249, it must be committed because of a
prohibited bias.306 Specifically, Section 249(a)(1) prohibits conduct committed because of the
victim’s “actual or perceived race, color, religion, or national origin.”307 Alternatively, Section
249(a)(2) criminalizes conduct committed because of bias against the victim’s actual or perceived
“religion, national origin, gender, sexual orientation, gender identity, or disability.”308 Section
249(a)(2) contains an additional jurisdictional requirement that Section 249(a)(1) does not:
specifically, that the conduct at issue must implicate interstate commerce.309 Section 249(a)(2)
outlines a variety of ways in which that may occur.310
Generally, the maximum penalty for Section 249 violations is a $250,000 fine, imprisonment for
up to ten years, or both.311 However, Congress has authorized longer prison terms in certain
instances, such as when the offense involves kidnapping or results in death.312 Since its
enactment, Section 249 has been used to prosecute a range of crimes with discriminatory motives,
including a racially motivated assault313 and a kidnapping and assault motivated by sexual
orientation bias.314 Federal prosecutors have also invoked Section 249 in high profile cases such

303 Section 249 defines “firearm” by reference to 18 U.S.C. § 921, which in turn defines “firearm” to mean “(A) any
weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the
action of an explosive; (B) the frame or receiver of any such weapon; (C) any firearm muffler or firearm silencer; or
(D) any destructive device. Such term does not include an antique firearm.” Id. §§ 249(a)(1), (c)(3); 921(a)(3).
304 Section 249 defines “explosive or incendiary device” by reference to 18 U.S.C. § 232, which in turn defines
“explosive or incendiary device” to mean “(A) dynamite and all other forms of high explosives, (B) any explosive
bomb, grenade, missile, or similar device, and (C) any incendiary bomb or grenade, fire bomb, or similar device,
including any device which (i) consists of or includes a breakable container including a flammable liquid or compound,
and a wick composed of any material which, when ignited, is capable of igniting such flammable liquid or compound,
and (ii) can be carried or thrown by one individual acting alone.” Id. §§ 232, 249(c)(2).
305 Id. § 249(a)(1).
306 Id. § 249.
307 Id. § 249(a)(1).
308 Id. § 249(a)(2).
309 Id. § 249(a)(2).
310 Id. § 249(a)(2)(B). The government may establish jurisdiction by showing that the conduct occurs during, or results
from “travel of the defendant or the victim . . . across a state line or national border” or involves “a channel, facility, or
instrumentality of interstate commerce.” Id. § 249(a)(2)(B). For example, in United States v. Jenkins, a federal court
concluded that an intrastate kidnapping and beating satisfied the jurisdictional element of § 249(a)(2) where the
defendant traveled on an interstate highway (a channel of interstate commerce) and used a car (an instrumentality of
commerce). 909 F. Supp. 2d 758, 771 (E.D. Ky. 2012). Alternatively, the government may also satisfy the interstate
commerce requirement by proving that the defendant “employ[ed] a firearm, dangerous weapon, explosive or
incendiary device, or other weapon that has traveled in interstate or foreign commerce.” 18 U.S.C. § 249(a)(2)(B)(iv).
An alternate jurisdictional hook for the statute involves conduct occurring in the special maritime or territorial
jurisdiction of the United States. Id. § 249(a)(3).
311 18 U.S.C. §§ 249(a)(1)-(2), id. § 3571.
312 Id. § 249.
313 Press Release, U.S. Dep’t of Justice, Arkansas Man Pleads Guilty to Federal Hate Crime Related to the Assault of
Five Hispanic Men (May 16, 2011), https://www.justice.gov/opa/pr/arkansas-man-pleads-guilty-federal-hate-crime-
related-assault-five-hispanic-men.
314 Press Release, U.S. Dep’t of Justice, Two Harlan County, Kentucky, Men Indicted for Federal Hate Crime Against
Individual Because of Sexual Orientation (Apr. 12, 2012), https://www.justice.gov/opa/pr/two-harlan-county-kentucky-
men-indicted-federal-hate-crime-against-individual-because-sexual.
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as the fatal shootings at Emanuel African Methodist Episcopal Church in Charleston, South
Carolina in 2015,315 and Tree of Life Synagogue in Pittsburgh, Pennsylvania in 2018.316
Crimes Involving Specific Weapons
One concern of federal law enforcement with respect to domestic terrorists has been their access
to, and potential use of, certain weapons.317 For example, in remarks about domestic terrorism in
2017, then-Deputy Attorney General Rosenstein cautioned that “[v]iolent domestic extremists
have . . . acquired biological and chemical weapons, illegal firearms, and explosives.”318 As
detailed above, a number of federal criminal statutes potentially applicable in the domestic
terrorism context prohibit certain conduct committed with a specific weapon—or authorize
increased penalties in such instances.319 Depending on the circumstances, a domestic terrorist’s
choice of weapon could also potentially violate numerous federal criminal statutes specifically
focused on regulating certain weapons.320 This section briefly summarizes federal criminal laws
governing three categories of weapons: (1) fire, explosives, and destructive devices; (2) firearms;
and (3) chemical or biological weapons.321
Fire, Explosives, and Destructive Devices
A number of federal criminal statutes impose penalties for certain conduct involving fire,
explosives, or similar means.322 This subsection discusses additional federal criminal laws
expressly restricting the use of fire, explosives, or destructive devices.

315 United States v. Roof, 225 F. Supp. 3d 438, 441 (D.S.C. 2016); Press Release, U.S. Dep’t of Justice, Federal Jury
Sentences Dylann Storm Roof to Death (Jan. 10, 2017), https://www.justice.gov/usao-sc/pr/federal-jury-sentences-
dylann-storm-roof-death.
316 Superseding Indictment, United States v. Bowers, No. 18-292, 2019 WL 720160 (W.D. Pa. Jan. 29, 2019); Press
Release, U.S. Dep’t of Justice, Additional Charges Filed in Tree of Life Synagogue Shooting (Jan. 29, 2019),
https://www.justice.gov/opa/pr/additional-charges-filed-tree-life-synagogue-shooting.
317 For instance, chemical and biological weapons have been described as a “most pressing concern,” Ten Years After
9/11: Hearing Before the Committee on Senate Homeland Security and Governmental Affairs, 112th Cong. (Oct. 18,
2011) https://archives.fbi.gov/archives/news/testimony/ten-years-after-9-11-and-the-anthrax-attacks-protecting-against-
biological-threats (statement of Vahid Majidi, Assistant Dir., Weapons of Mass Destruction Directorate, FBI), within
the FBI’s larger priority of “[p]rotect[ing] the United States from terrorist attack.” Organization, Mission and
Functions Manual: Federal Bureau of Investigation, U.S. Dep’t of Justice, https://www.justice.gov/jmd/organization-
mission-and-functions-manual-federal-bureau-investigation (last visited Apr. 2, 2021); see also CRS In Focus IF10651,
The Federal Bureau of Investigation: Just the Facts, by Nathan James and Jerome P. Bjelopera (describing
“thwart[ing] terrorists” as one of the FBI’s “first two priorities,” an effort that includes the “Weapons of Mass
Destruction Directorate” that “coordinates efforts designed to prevent the use of chemical, biological, radiological, and
nuclear weapons”).
318 Deputy Attorney General Rosenstein, Remarks at the 10th Annual Utah National Security and Anti-Terrorism
Conference (Aug. 30, 2017), https://www.justice.gov/opa/speech/deputy-attorney-general-rosenstein-delivers-remarks-
10th-annual-utah-national-security-0; see also Deputy Attorney General Carlin, Remarks at the National Summit on
Homeland Security Law (Apr. 18, 2015), https://www.justice.gov/opa/speech/assistant-attorney-general-carlin-
delivers-remarks-national-summit-homeland-security-law (“domestic extremists . . . have amassed illegal weapons,
explosives, and biological and chemical weapons; and they have gone on killing sprees that have terrorized local
communities.”).
319 See, e.g., supra § “Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act of 2009: 18 U.S.C. § 249.”
320 See, e.g., 18 U.S.C. § 1716 (prohibiting the knowing mailing of explosives, among other things).
321 There is unavoidable overlap between these categories. For example, a statute may govern both firearms and
destructive devices such as explosives. E.g., id. § 922.
322 See supra, § “Hate Crimes.”
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For example, Sections 842 and 844 of Title 18 of the U.S. Code contain a lengthy set of
provisions that stringently regulate “explosive materials” and prohibit certain conduct involving
explosives.323 The term “explosive materials” is defined to include “any chemical compound
mixture, or device, the primary or common purpose of which is to function by explosion.”324 A
comprehensive, though not exclusive, list of explosive materials is published annually in the
Federal Register.325
For items meeting the statutory definition of “explosive materials,” Section 842(a)(3) prohibits
their knowing receipt or transport by any person who does not have a federal license or permit.326
Section 842(i) also separately prohibits the knowing transport, receipt, or possession of an
explosive in or affecting interstate or foreign commerce by any person who falls into at least one
of seven categories:
 indicted or convicted felons,
 fugitives from justice,
 addicts and unlawful users of controlled substances,
 those with certain mental health statuses,
 certain aliens,
 those dishonorably discharged from the armed forces, and
 U.S. citizens who have renounced their citizenship.327
“Knowing” receipt, transport, or possession for purposes of Section 842 requires that a person
know that the objects have “the characteristics that [bring] them within the statutory definition of
an explosive,” e.g., that they are “primarily designed to function by explosion.”328 Following a
Supreme Court decision interpreting a “nearly identical”329 statute governing firearms, Section
842(i) also likely requires knowledge that a person falls into at least one of the prohibiting
categories listed above.330 Violations of Sections 842(a)(3) and 842(i) are punishable by fines and
up to ten years in prison.331
Separate from Section 842, Section 844 of Title 18 of the U.S. Code prohibits “maliciously”
using means of “fire or an explosive” to damage or destroy (or attempt to damage or destroy) a
building, vehicle, or other real or personal property that is either (1) owned, possessed, or leased
by the federal government or any institution or organization receiving federal financial assistance;
or (2) used in interstate or foreign commerce or an activity affecting interstate or foreign
commerce.332 Transporting or receiving an explosive in interstate or foreign commerce “with the

323 18 U.S.C. §§ 842, 844.
324 Id. § 841(c)-(d).
325 See Commerce in Explosives; 2020 Annual List of Explosive Materials, 85 Fed. Reg. 83999, 83999-84001 (Dec. 23,
2020).
326 18 U.S.C. § 842(a)(3).
327 Id. § 842(i).
328 United States v. Markey, 393 F.3d 1132, 1136 (10th Cir. 2004).
329 Id. at 1135.
330 See Rehaif v. United States, 139 S. Ct. 2191, 2194 (2019) (“We hold that the word ‘knowingly’ applies both to the
defendant’s conduct and to the defendant’s status.”).
331 18 U.S.C. § 844(a)(1).
332 Id. § 844(f)(1), (i).
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knowledge or intent that it will be used” for the same purpose is prohibited, as well.333 The term
“explosive” is defined separately for purposes of Section 844 as including (among other things)
incendiary devices (such as “Molotov cocktails”),334 and other compounds, mixtures, and devices
containing combinations of ingredients that may cause explosion when ignited.335 To engage
“maliciously” in the proscribed conduct, one must act intentionally or “with willful disregard of
the likelihood that damage or injury [will] result from his or her acts.”336 Additionally, given the
limitation that non-federal property protected by the statute must be used in commerce “or an
activity affecting” commerce, the provision reaches only property that is in “active employment
for commercial purposes” and not, for example, owner-occupied private residences.337 Violations
of the Section 844 arson provisions involving actual use of fire or an explosive (rather than mere
receipt or transport) are subject to a five-year mandatory minimum sentence of imprisonment,
which is increased to seven years if personal injury results.338 Statutory maximum sentences also
depend on the consequences resulting from the proscribed conduct—if death results, a person
may be subject to the death penalty or to life imprisonment.339
Prosecutors have used Sections 842 and 844 to charge individuals for a range of alleged conduct
such as setting fire to police vehicles,340 and interstate transportation of explosives in connection
with the “mailing [of] 16 improvised explosive devices . . . to 13 victims throughout the country,
including 11 current or former U.S. government officials.”341
Another example, the National Firearms Act (NFA), codified at Chapter 53 of Title 26 of the U.S.
Code, generally limits the availability of certain kinds of weapons through a detailed taxation and
registration system.342 Among other things, Section 5861 makes it unlawful to receive, possess, or
transfer a covered weapon without paying applicable taxes and ensuring the weapon is
appropriately registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives.343 One
category of weapon subject to the NFA is a “destructive device,” which is defined to include “any
explosive, incendiary, or poison gas (A) bomb, (B) grenade, (C) rocket having a propellant charge
of more than four ounces, (D) missile having an explosive or incendiary charge of more than one-
quarter ounce, (E) mine, or (F) similar device.”344 To violate Section 5861, one must “know the
characteristics of a [weapon] that bring it within the NFA’s ambit,” but one need not know the

333 Id. § 844(d).
334 Id. § 232(5); see also United States v. Reed, 726 F.2d 570, 574 (9th Cir. 1984) (describing Molotov cocktails as an
example of an incendiary device for purposes of § 232(5)).
335 18 U.S.C. § 844(j).
336 United States v. Whaley, 552 F.3d 904, 907 (8th Cir. 2009).
337 Jones v. United States, 529 U.S. 848, 855-56 (2000).
338 18 U.S.C. § 844(f), (i).
339 Id. § 844(f)(3), (i).
340 Press Release, U.S. Dep’t of Justice, Three Men Face Federal Arson Charges For Setting Fire To Police Patrol
Vehicle During Protest In Downtown Las Vegas (June 4, 2020), https://www.justice.gov/usao-nv/pr/three-men-face-
federal-arson-charges-setting-fire-police-patrol-vehicle-during-protest; William K. Rashbaum & Andrea Salcedo, Two
Lawyers Arrested in Molotov Cocktail Attack on Police in Brooklyn, N.Y. TIMES (May 31, 2020),
https://www.nytimes.com/2020/05/31/nyregion/nyc-protests-lawyer-molotov-cocktail.html.
341 Sayoc Plea Press Release, supra note 126.
342 CRS Report R45629, Federal Firearms Laws: Overview and Selected Legal Issues for the 116th Congress, by
Michael A. Foster, at 3-5.
343 26 U.S.C. § 5861.
344 Id. § 5845(f).
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requirements that make receipt, possession, or transfer unlawful (e.g., that a covered weapon is
unregistered).345 Violators of the NFA are subject to fines and imprisonment of up to ten years.346
A separate set of provisions collectively known as the Gun Control Act (GCA), primarily codified
at Chapter 44 of Title 18 of the U.S. Code, impose further restrictions on the possession of most
kinds of firearms, which are defined to include destructive devices.347 Among other things,
Section 922(g) of Title 18 of the U.S. Code establishes categories of persons who, because of
risk-related characteristics, may not possess such devices in or affecting commerce.348 The
categories of excluded persons are similar to those described above under Section 842 and
include, among others, convicted felons, fugitives from justice, and unlawful users or addicts of
controlled substances.349 To be convicted under the GCA, a person must knowingly possess the
device and must know his or her prohibited status as well (e.g., that he or she is a convicted
felon).350 Violations of many of the prohibitions contained in the GCA and supplementing statutes
are punishable as felonies, subjecting violators to criminal fines and statutory imprisonment
ranges of varying lengths.351 Increased penalties are also tied to transporting or receiving
destructive devices in interstate or foreign commerce with intent to use them (or with knowledge
they will be used) to commit separate felony crimes, as well as using, carrying, or possessing
such devices in connection with “any crime of violence or drug trafficking crime.”352
Prosecutions under Section 922(g) have included, among others, an individual who allegedly left
a backpack full of explosive devices in downtown Pittsburgh,353 and an individual who had
previously been convicted of a felony and allegedly carried a Molotov cocktail during a protest in
Jacksonville.354
Firearms
Various federal statutes, including some discussed above,355 criminalize certain conduct involving
firearms.356 A thorough review of the federal firearm statutory regime is beyond the scope of this
report, and may be found in other CRS products.357 Nevertheless, as an illustration, one federal
firearms law that could be applicable in the context of domestic terrorism is the GCA, discussed
above.358 Among other things, that law makes it a crime for certain categories of prohibited

345 United States v. Cox, 906 F.3d 1170, 1194-95 (10th Cir. 2018).
346 26 U.S.C. § 5871.
347 18 U.S.C. § 921(a)(3)
348 Id. § 922(g).
349 Id.
350 Rehaif v. United States, 139 S. Ct. 2191, 2194 (2019).
351 18 U.S.C. § 924.
352 Id. § 924(a)(7)(b), (a)(7)(c)(1)(A)
353 Press Release, U.S. Dep’t of Justice, Pittsburgh Man Indicted for Possessing Destructive Devices (June 23, 2020),
https://www.justice.gov/usao-wdpa/pr/pittsburgh-man-indicted-possessing-destructive-devices.
354 Press Release, U.S. Dep’t of Justice, Jacksonville Man Indicted For Possession Of Molotov Cocktail At Protest
(June 10, 2020), https://www.justice.gov/usao-mdfl/pr/jacksonville-man-indicted-possession-molotov-cocktail-protest.
355 See, e.g., supra “Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act of 2009: 18 U.S.C. § 249.”
356 See, e.g., 18 U.S.C. § 930(c) (prohibiting killing during attack on federal facility involving firearm (§ 930(c) is a
predicate offense for 18 U.S.C. § 2339A discussed above))
357 See generally Foster, supra note 342.
358 Supra “Fire, Explosives, and Destructive Devices.”
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persons to ship, transport, possess, or receive any firearms or ammunition.359 As with the GCA
provisions concerning destructive devices discussed in the previous subsection, conviction for
possession of a firearm by a prohibited person requires the defendant’s knowledge (1) that he
possesses the firearm, and (2) of his prohibited status.360 Penalties for violations of the GCA are
generally punishable as felonies and subject to various fines and sentencing ranges. 361 Depending
on the circumstances, other federal firearms laws that may be applicable to domestic terrorism
include those criminalizing transfer or possession of certain unregistered firearms,362
machineguns,363 and firearms undetectable by “x-ray machines or metal detectors at security
checkpoints.”364
Chemical or Biological Weapons
A number of federal criminal statutes regulate the creation, transfer, or use of chemical or
biological weapons, including some of the statutes contained in Chapter 113B of Title 18 of the
U.S. Code, which expressly focuses on terrorism.365 In addition, Section 175 of Title 18 imposes
penalties of up to life imprisonment for anyone who “knowingly develops, produces, stockpiles,
transfers, acquires, retains, or possesses any biological agent . . . for use as a weapon,” or
threatens to do so.366 Among other things, biological agents include a range of substances
including microorganisms and infectious substances (or their components) “capable of causing . .
. death” or disease in a human.367 Section 175 only governs biological agents intended “for use as
a weapon,” and excludes biological agents used for “prophylactic, protective, bona fide research,
or other peaceful purposes.”368 Section 175 prosecutions are somewhat rare, but have included,
for example, the prosecution of an individual who attempted to acquire “the lethal biological
toxin ricin.”369
Another potentially relevant statute is Section 229 of Title 18 of the U.S. Code, which in general
makes it a crime to knowingly “develop, produce, otherwise acquire, transfer directly or
indirectly, receive, stockpile, retain own, possess, or use, or threaten to use, any chemical
weapon.”370 A “chemical weapon” for the purposes of Section 229 may include “[a] toxic
chemical and its precursors,” munitions or devices “specifically designed to cause death or other
harm through toxic properties of those toxic chemicals,” or certain related equipment.371 A toxic

359 18 U.S.C. 922(g). The provision requires receipt, shipping, or transportation to be “in interstate or foreign
commerce” and possession to be “in or affecting commerce.” Id.
360 Rehaif v. United States, 139 S. Ct. 2191, 2194 (2019).
361 18 U.S.C. § 924.
362 26 U.S.C. § 5861(d)-(e).
363 18 U.S.C. § 922(o).
364 Foster, supra note 342, at 15.
365 Supra, § “Remaining Chapter 113B Offenses.”
366 18 U.S.C. § 175 (§ 175 is a predicate offense for 18 U.S.C. § 2339A discussed above)). Another related statute
imposes criminal penalties on the transfer, receipt, or possession of biological agents by “restricted persons”—which
may include, among others, convicted felons, fugitives from justice, or unlawful users of controlled substances. Id. §
175b (§ 175(b) is a predicate offense for 18 U.S.C. § 2339A discussed above)).
367 Id. § 178(1).
368 Id. § 175(c)
369 United States v. Le, 902 F.3d 104, 106 (2d Cir. 2018); see also United States v. Crump, 609 F. App’x 621, 622 (11th
Cir. 2015) (affirming § 17 conviction of defendant for possession of castor beans, which contained ricin),
370 18 U.S.C. § 229. Section 229 is a predicate offense for 18 U.S.C. § 2339A discussed above.
371 Id. § 229F(1).
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chemical, meanwhile, includes “any chemical which . . . can cause death, temporary
incapacitation or permanent harm to humans or animals.”372 Notably, the statute exempts various
government actors who are in possession of a weapon pending its destruction.373 Violations of
Section 229 generally result in fines or up to life imprisonment, or both, or death in the case of
fatal violations.374 As with Section 175, prosecutions under Section 229 appear to be relatively
rare.375 However, DOJ has used Section 229 to charge conduct such as possession of “77 grams of
75% pure potassium cyanide [that] could kill 450 people in its solid form,”376 the attempted
acquisition of nerve gasses possibly to “strik[e] a federal courthouse,”377 and the placement of a
chlorine bomb at a residence.378 One notable illustration of Section 229’s applicability to
domestic terrorism is United States v. Kimber where the U.S. Court of Appeals for the Second
Circuit affirmed the Section 229 conviction of a disgruntled patient who dispersed “elemental
mercury” (a neurotoxin) throughout a medical facility.379 The court cited to the federal definition
of domestic terrorism and concluded that the patient’s conduct was “quintessential terrorism”
because his purpose was to “coerc[e] and intimidat[e] the public into forgoing treatment at the
[medical facility].”380
There is an important limit to statutes like Sections 175 and 229: pursuant to Supreme Court
precedent, they do not govern local conduct subject to state law, such as routine assaults that
happen to involve biological agents or toxic chemicals.381 Rather, as the Court noted, federal
biological and chemical weapons statutes have as “core concerns,” “acts of war, assassination,
and terrorism” and do not reach “the simplest of assaults.”382 In determining whether local
conduct is involved in a given prosecution, courts would likely evaluate the dangerousness of the
weapon at issue and the potential or actual harm caused by that weapon.383 Presumably, domestic
terrorism would qualify as a “core concern” of Sections 175 and 229, and therefore not amount to
the type of conduct outside the scope of these statutes.384
Crimes Involving Threats
In certain circumstances, acts of domestic terrorism may consist at least in part of threats.385 For
example, DOJ prosecuted an individual for a five-day crime spree it described as a “domestic

372 Id. § 229F(8)(A).
373 Id. § 229(b).
374 Id. § 229A(a)(1)-(2).
375 See Bond v. United States, 572 U.S. 844, 863 (2014) (“The Government has identified only a handful of
prosecutions that have been brought under [Section 229].”).
376 United States v. Ghane, 673 F.3d 771, 776 n.3 (8th Cir. 2012).
377 United States v. Crocker, 260 F. App’x 794, 796 (6th Cir. 2008).
378 United States v. Fries, No. CR-11-1751-TUC-CKJ, 2012 WL 689157, at *1 (D. Ariz. Feb. 28, 2012).
379 777 F.3d 553, 556-57 (2d Cir. 2015).
380 Id. at 561-62.
381 Bond v. United States, 572 U.S. 844, 848 (2014); see also United States v. Levenderis, 806 F.3d 390, 397 (6th Cir.
2015) (“[G]iven the similarities between § 175 and § 229, we follow the Supreme Court's instruction and interpret
§ 175 in light of federalism principles, just as it did with § 229.”).
382 Bond, 572 U.S. at 863.
383 See Levenderis, 806 F.3d at 397 (determining whether defendant’s use of biological weapon was local conduct
based on level of dangerousness of weapon).
384 See, e.g., United States v. Crocker, 260 F. App’x 794, 795-96 (6th Cir. 2008) (affirming § 229 prosecution of
defendant who attempted to obtain components for chemical weapon as part of plot to attack federal buildings).
385 A concern related to threats may be hoaxes. See, e.g., Think Before You Post: Hoax Threats are Serious Federal
Crimes, FBI, https://www.fbi.gov/news/stories/hoax-threats-awareness-100518 (last visited Apr. 4, 2021) (describing
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terror attack,” where the individual engaged in various behaviors such as mailing explosive
devices to “current or former government officials” and conveying threats in interstate commerce,
among other things.386 Many of the federal criminal statutes discussed above prohibit some
threats,387 including several of the statutes expressly prohibiting terrorism.388 In addition to these
examples, Sections 875 and 876 of Title 18 of the U.S. Code authorize various prison terms for
threatening to injure or kidnap another or threatening a person’s property or reputation.389 To
violate Section 875, the threat must be transmitted in “interstate or foreign commerce,”390 while
to violate Section 876, the threat must be sent through the mail.391 Given their similarity, courts
often construe Sections 875 and 876 in relation to each other.392 Pursuant to Supreme Court
precedent, federal courts have generally interpreted both statutes to require subjective intent to
threaten on the part of the defendant.393 In addition, a number of federal courts have also required

harm posed by hoax threats). Hoaxes may violate a federal statute that makes it a crime to engage in “any conduct with
intent to convey false or misleading information under circumstances where such information may reasonably be
believed and where such information indicates that an activity has taken, is taking, or will take place that would
constitute a violation” one of several chapters of the federal criminal code, including those governing terrorism and
firearms, among others. 18 U.S.C. § 1038. DOJ has used the federal hoax statute to prosecute conduct such as reporting
false bomb threats to law enforcement. Press Release, U.S. Dep’t of Justice, Massachusetts Man Sentenced to More
than 17 Years in Prison for Cyberstalking Former Housemate and Others, Computer Hacking, Sending Child
Pornography and Making Over 100 Hoax Bomb Threats (Oct. 3, 2018), https://www.justice.gov/opa/pr/massachusetts-
man-sentenced-more-17-years-prison-cyberstalking-former-housemate-and-others.
386 Sayoc Plea Press Release, supra note 126.
387 Supra, § “Substantive Criminal Laws.”
388 Supra, § “Federal Criminal Terrorism Laws.”
389 18 U.S.C. §§ 875(b)-(d), 876(b)-(d). Both statutes also prohibit certain ransom demands made in connection to
kidnappings. Id.
390 Id. § 875.
391 Id. § 876.
392 See United States v. Spatig, 870 F.3d 1079, 1084 (9th Cir. 2017) (describing Sections 875 and 876 as “near twin[s]”
and explaining that both require identical intent); see also United States v. Nicholas, 844 F. App'x 609, 611, n.1 (4th
Cir. 2021) (“[T]he statutory language in § 875 and § 876 are nearly identical except for the jurisdictional element of
interstate commerce versus the mail.”); United States v. Stoner, 781 F. App’x 81, 85 (3d Cir. 2019), cert. denied, 140 S.
Ct. 2676 (2020) (construing Sections 875 and 876 together); United States v. Haddad, 652 F. App’x 460, 461 (7th Cir.
2016) (similar).
393 In the context of Section 875, the Supreme Court held in Elonis v. United States that, at a minimum, the defendant’s
conduct must rise above the level of negligence. 575 U.S. 723, 740 (2015). The Court reasoned that the “mental state
requirement in Section 875(c) is satisfied if the defendant transmits a communication for the purpose of issuing a
threat, or with knowledge that the communication will be viewed as a threat.” Id. However, the Court expressly
declined to consider whether mere recklessness is sufficient to satisfy the mental state requirement. Id. at 741.
Following Elonis, a number of federal courts have construed Sections 875 and 876 to require subjective intent to
threaten on the part of the defendant. United States v. Howard, 947 F.3d 936, 946 (6th Cir. 2020) (concluding, pursuant
to Elonis, that the defendant must have “intended the message as a threat”); United States v. Dierks, 978 F.3d 585, 591
(8th Cir. 2020) (“[Following Elonis] the key question for mens rea is whether the defendant trasmit[ted] a
communication for the purpose of issuing a threat or with knowledge that the communication [would] be viewed as a
threat.” (internal quotation marks omitted)); Stoner, 781 F. App’x at 85 (citing Elonis for proposition defendant must
transmit a communication with the purpose of threatening someone or with the knowledge that the communication
would be interpreted as a threat); United States v. Khan, 937 F.3d 1042, 1051 (7th Cir. 2019) (construing § 875 in light
of Elonis to require that “the communication was transmitted for the purpose of issuing a threat, or with knowledge that
the communication would be viewed as a threat”); Haddad, 652 F. App’x at 461 (“To secure convictions under §
875(c) and § 876(c), it would have been enough for the government to prove that Haddad had sent communications that
were intended and reasonably perceived as being threatening.”); United States v. White, 810 F.3d 212, 220-21 (4th Cir.
2016) (requiring government to prove subjective intent to threaten on part of defendant in light of Elonis in §875
conviction); Nicholas, 2019 WL 3774622, at *2 (“To prove guilt under 18 U.S.C. § 876(c), the government must prove
that the defendant subjectively intended the mailing as a threat.”). Mirroring Elonis, at least one federal court has
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that the defendant transmit the threat knowingly as opposed to mistakenly.394 In light of First
Amendment speech protections, federal courts have interpreted Sections 875 and 876 as
prohibiting only true threats395— statements conveying “an intent to commit an act of unlawful
violence to a particular individual or group of individuals.”396 In determining whether a statement
is a true threat for the purposes of Sections 875 and 876, courts consider whether a reasonable
person would have considered the statement to be a threat.397
Crimes Involving Computers
At first glance, the concept of computer crime—with its connotations of illicit virtual conduct—
may appear somewhat removed from the federal definition of domestic terrorism, which is
focused on “acts dangerous to human life.”398 However, there may be overlap. The rise of
internet-enabled computerized devices and objects—ranging from smart appliances to vehicles to
infrastructure399—has potentially created new opportunities for cybercriminals to exact real world
consequences through computer intrusion.400 Although much of the cyberterrorism concern may

declined to weigh in on whether a reckless mental state could also suffice for the purposes of the federal threat statutes.
White, 810 F.3d at 222 n.3.
394 See Khan, 937 F.3d at 1051 (“[A] conviction under § 875(c) requires . . . the knowing transmission in interstate
commerce of a communication”); United States v. Chapman, 866 F.3d 129, 136 (3d Cir. 2017) (“Accordingly, 18
U.S.C. § 876(c) . . . requires knowingly mailing a communication containing a threat.”); White, 810 F.3d at 220-21
(holding that § 875 requires that a defendant “knowingly transmitted a communication in interstate or foreign
commerce”); United States v. Baker, No. 4:21-MJ-09-MAF, 2021 WL 318311, at *3 (N.D. Fla. Jan. 25, 2021) (finding
that there was probable cause of knowing transmission of a threat in violation of § 875 where “there [was] no indication
that the Defendant accidently or mistakenly posted these communications”).
395 See White, 810 F.3d at 220-21 (holding that prosecution under Section 875 requires proof that “the content of the
communication contained a ‘true threat’ to kidnap or injure”); United States v. Wolff, 370 F. App’x 888, 892 (10th Cir.
2010) (“The First Amendment, therefore, permits conviction under Section 876(c) only if the communication at issue
constitutes a ‘true threat.’”); United States v. Worrell, 313 F.3d 867, 874 (4th Cir. 2002) (similar); see also United
States v. Nishnianidze, 342 F.3d 6, 14-15 (1st Cir. 2003) (“To convict under § 875, the government had to prove that
the defendant intended to transmit the interstate communication and that the communication contained a true threat.”);
United States v. Sovie, 122 F.3d 122, 125 (2d Cir. 1997) (similar); United States v. Musgrove, 845 F. Supp. 2d 932,
945 (E.D. Wis. 2011) (“Because 18 U.S.C. § 875(c) criminalizes pure speech, the government must prove that an
allegedly unlawful communication contains a ‘true threat.’”).
396 Virginia v. Black, 538 U.S. 343, 359 (2003). For an examination of “true threats,” see generally CRS Report
R45713, Terrorism, Violent Extremism, and the Internet: Free Speech Considerations, by Victoria L. Killion. True
threats are a regulable category of speech under the First Amendment. See generally CRS In Focus IF11072, The First
Amendment: Categories of Speech, by Victoria L. Killion.
397 See Stoner, 781 F. App’x at 85 (explaining that both Sections 875 and 876 require proof that the defendant
transmitted a communication that objectively would be viewed as a threat by a reasonable person); White, 810 F.3d at
220-21 (describing Section 875 as requiring that the content of the communication amount to a true threat, which
requires the government to prove that “an ordinary, reasonable recipient who is familiar with the context in which the
statement is made would interpret it as a serious expression of an intent to do harm”); see also Howard, 947 F.3d at 946
(listing as an element of a § 875(c) violation that “a reasonable observer would view the message as a threat”); United
States v. Stevens, 881 F.3d 1249, 1253 (10th Cir. 2018) (similar).
398 18 U.S.C. § 2331(5)(A).
399 See generally Understanding the Role of Connected Devices in Recent Cyber Attacks: Hearing Before H. Comm. on
Energy and Commerce, 114th Cong. 3 (2016) (statement of Bruce Schneier) [hereinafter Schneier testimony]
(explaining the scope of computerization and how as a result the internet “now affects the world in a direct physical
manner”); see also H.R. REP. NO. 98-894, at 10 (1984) (“[B]y combining the ubiquity of the telephone with the
capability of the personal computer, a whole new dimension of criminal activity becomes possible.”).
400 For example, “in 2008, a fourteen-year-old boy hacked into the system controlling the trains of Lodz, Poland as a
prank” and “made several trains change tracks, causing multiple derailments and injuries.” Sara Sun Beale & Peter
Berris, Hacking the Internet of Things: Vulnerabilities, Dangers, and Legal Responses, DUKE L. & TECH. REV.,
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be international in scope,401 it is at least conceivable that domestic terrorists could exploit
computer vulnerabilities in a manner dangerous to human life.402 To the extent such conduct
involves hacking, it could violate the Computer Fraud and Abuse Act (CFAA), 18 U.S.C. § 1030,
a civil and criminal law, often described as the preeminent federal anti-hacking law,403 which
imposes a range of penalties for illicit computer-based behaviors.404
For example, installing malicious software on an internet-enabled computerized device to cause it
to malfunction dangerously could violate Section 1030(a)(5)(A).405 Among other things, that
subsection prohibits the unauthorized transmission of “a program, information, code, or
command” that damages protected computers406 (any computer connected to the internet). 407 The
phrase “program, information, code, or command” broadly includes “all transmissions that are
capable of having an effect on a computer’s operation,” such as worms, “software commands
(such as an instruction to delete information),” and “network packets designed to flood a network
connection or exploit system vulnerabilities.”408 Transmission may occur through use of the
internet or physical mediums like compact discs.409 Some courts have concluded, however, that
the exact means of transmission is irrelevant, focusing instead on whether the program,
information, code, or command caused damage.410 Damage means “impairment to the integrity or
availability of data, a program, a system, or information,”411 which occurs, for example, where a
hacker causes a computer to behave in a manner contrary to its owner’s intentions.412 A thorough

February 14 2018, at 161, 165.
401 See, e.g., FBI Oversight Hearing, supra note 2 (statement of Christopher Wray, Dir., FBI) (discussing “a huge range
of other cyber threats from nation states, criminals, and toxic combinations of the two. Like the vast unrelenting
counterintelligence threat from China.”).
402 A discussion of the various possibilities is necessarily speculative and beyond the scope of this report, but may be
found elsewhere. See generally Schneier testimony, supra note 399; Beale, supra note 400.
403 E.g., Ivan Evtimov et al., Is Tricking A Robot Hacking?, 34 BERKELEY TECH. L.J. 891, 904 (2019) (“Since its
implementation, the CFAA has been the nation’s predominant anti-hacking law.”).
404 18 U.S.C. § 1030.
405 Section 1030(a)(5)(A) is a predicate offense for 18 U.S.C. § 2339A discussed above.
406 18 U.S.C. § 1030(a)(5)(A).
407 See, e.g., hiQ Labs, Inc. v. LinkedIn Corp., 938 F.3d 985, 999 (9th Cir. 2019) (“The term ‘protected computer’
refers to any computer ‘used in or affecting interstate or foreign commerce or communication,’ . . . effectively any
computer connected to the Internet . . . including servers, computers that manage network resources and provide data to
other computers.” (quoting 18 U.S.C. § 1030(e)(2)(B)) (internal citations omitted)).
408 U.S. DEP’T OF JUSTICE, COMPUTER CRIME & INTELLECTUAL PROPERTY SECTION, CRIMINAL DIVISION, PROSECUTING
COMPUTER CRIMES, 37 (2015), https://www.justice.gov/sites/default/files/
criminal-ccips/legacy/2015/01/14/ccmanual.pdf.
409 Beale, supra note 400, at 170 (citing Deborah F. Buckman, Annotation, Validity, Construction, and Application of
Computer Fraud and Abuse Act (18 U.S.C.A. § 1030), 174 A.L.R. FED. 101 (2001)); accord United States v. Sullivan,
40 F. App’x 740, 743-44 (4th Cir. 2002) (per curiam) (concluding that a transmission under 18 U.S.C. § 1030(a)(5)(A)
occurred through insertion of code into a computer system that eventually found its way into hand-held computers); N.
Tex. Preventive Imaging LLC v. Eisenberg, No. SA CV 96-71AHS (EEX), 1996 WL 1359212, at *6 (C.D. Cal. Aug.
19, 1996) (“The transmission of a disabling code by floppy computer disk may fall within . . . [§ 1030(a)(5)(A)], if
accompanied by the intent to cause harm.”).
410 See, e.g., Patrick Patterson Custom Homes, Inc. v. Bach, 586 F. Supp. 2d 1026, 1035 (N.D. Ill. 2008) (“While
Plaintiffs acknowledge that the precise method of installation of the erasure program is unknown, the Seventh Circuit
recognizes that the precise mode of transmission is irrelevant.”).
411 18 U.S.C. § 1030(e)(8).
412 See United States v. Yücel, 97 F. Supp. 3d 413, 420 (S.D.N.Y. 2015) (construing damage under § 1030(a)(5) to
include instances where a computer is caused to “no longer operate[] only in response to the commands of the owner”).
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analysis of this and other substantive provisions of the CFAA exceeds the scope of this report, but
is available in other CRS products.413
Computers and the internet may pose other issues with respect to domestic terrorism, such as the
use of social media to coordinate plots.414 There may also be constitutional and privacy concerns
with respect to the government acquisition of data to combat domestic terrorism, among other
things.415
Inchoate and Accomplice Liability
As identified above, in many of the statutes establishing federal offenses that overtly relate, or
may be applied, to conduct meeting at least one definition of domestic terrorism, conspiracies and
attempts are also proscribed.416 Additionally, some of the federal offenses addressed above are
themselves inchoate417—for instance, 18 U.S.C. § 2384 prohibits seditious conspiracies, and 18
U.S.C. § 2101 prohibits taking certain preliminary actions with intent to incite or participate in
rioting, among other things.418 The conspiracy offenses expressly provided for in particular
statutes may have their own, unique requirements. However, federal law more broadly
criminalizes any conspiracy to commit another federal offense.419 Although there is no general
federal attempt provision, the components of an attempt, as prohibited in many federal criminal
statutes, are well-recognized.420 Separately, 18 U.S.C. § 373 prohibits soliciting another to
commit a federal violent felony.421 And 18 U.S.C. § 2 establishes accomplice liability for anyone
who “aids, abets, counsels, commands, induces or procures” the commission of any federal
offense.422 As such, one does not necessarily need to meet all of the elements of the offenses
described in this report through one’s own conduct for such offenses to be applicable, if the
requirements for conspiracy, attempt, solicitation, or accomplice liability are met. This section
provides an overview of these alternative and additional means of establishing federal criminal
liability in relation to conduct that may constitute domestic terrorism.423

413 See generally CRS Report 97-1025, Cybercrime: An Overview of the Federal Computer Fraud and Abuse Statute
and Related Federal Criminal Laws, by Charles Doyle; CRS Report R46536, Cybercrime and the Law: Computer
Fraud and Abuse Act (CFAA) and the 116th Congress, by Peter G. Berris.
414 Infra, § “Terrorist Speech and the Internet.” Another issue addressed in other CRS products is the potential use of
end-to-end encryption to conceal such plots. See generally CRS In Focus IF11769, Law Enforcement and Technology:
the “Lawful Access” Debate, by Kristin Finklea; CRS Report R44481, Encryption and the “Going Dark” Debate, by
Kristin Finklea; CRS Legal Sidebar LSB10416, Catch Me If You Scan: Constitutionality of Compelled Decryption
Divides the Courts, by Michael A. Foster; CRS Report R44642, Encryption: Frequently Asked Questions, by Chris
Jaikaran.
415 Infra, § “Fourth Amendment.”
416 See supra, §§ “Federal Criminal Terrorism Laws;” “Other Federal Criminal Laws Applicable to Domestic
Terrorism.”
417 Attempt, conspiracy, and solicitation are commonly referred to as “inchoate” offenses in the sense that they are
“forms of introductory misconduct that the law condemns lest they result in some completed form of misconduct.”
Doyle, Conspiracy, supra note 48, at 15.
418 See supra, § “Anti-Riot Act: 18 U.S.C. § 2101;” “Seditious Conspiracy: 18 U.S.C. § 2384.”
419 18 U.S.C. § 371.
420 See generally CRS Report R42001, Attempt: An Overview of Federal Criminal Law, by Charles Doyle.
421 18 U.S.C. § 373(a).
422 Id. § 2(a). Section 2 also permits punishment if one “willfully causes an act to be done which if directly performed
by him or another would be” a federal offense. Id. § 2(b).
423 The information in this section is drawn in significant part from three other CRS reports: Doyle, Conspiracy, supra
note 48; Doyle, Attempt, supra note 420; and CRS Report R43769, Accomplices, Aiding and Abetting, and the Like: An
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Conspiracy
18 U.S.C. § 371 makes it a crime for “two or more persons [to] conspire . . . to commit any
[federal] offense,” if “one or more of such persons do any act to effect the object of the
conspiracy.”424 “[T]he essence of a conspiracy is an agreement to commit an unlawful act.”425 Put
simply, a conspiracy is “a joint commitment to an endeavor which, if completed, would satisfy all
of the elements of the underlying substantive criminal offense.”426 Though a party to a
conspiratorial agreement does not have to intend to commit an underlying offense him or herself,
he or she must specifically intend for someone to consummate the unlawful object of the
conspiracy.427 Additionally, under Section 371,428 at least one of the parties to the conspiracy must
perform an “overt act” in its furtherance.429 However, the overt act need not be criminal, nor even
an element of the object crime or another crime.430
Where these elements are met, a conspiracy to commit a federal crime may be punished under
Section 371 as a crime in its own right, whether or not the object crime is completed.431 That said,
if the crime that is the objective of the conspiracy is carried out, a party to the conspiracy may
also separately be charged with that crime,432 as well as any other foreseeable crime committed in
furtherance of the conspiracy.433 Accordingly, Section 371 may be a distinct charge in many cases
where there is concerted action in connection with other statutes described in this report that are
related or applicable to domestic terrorism. Those who participate in domestic terrorism
conspiracies under Section 371 may be liable for other crimes described in this report or
elsewhere that are committed by co-conspirators. Violations of Section 371 are punishable by
fine, imprisonment for up to five years (in the case of an object crime that is a felony), or both.434
Attempt
A number of the statutes addressed in this report that establish offenses related or applicable to
domestic terrorism also proscribe attempts to commit said offenses.435 Attempt encompasses those
actions taken by individuals who intend to commit an offense and perform “an overt act

Overview of 18 U.S.C. § 2, by Charles Doyle.
424 18 U.S.C. § 371.
425 United States v. Jimenez Recio, 537 U.S. 270, 274 (2003) (quoting Iannelli v. United States, 420 U.S. 770, 777
(1975)) (internal quotation marks omitted). Because a conspiracy requires the agreement of at least two people, no
conspiracy can exist if the agreement is with an undercover government agent or other party who is only feigning
assent. E.g., United States v. Leal, 921 F.3d 951, 959 (10th Cir. 2019).
426 United States v. Annamalai, 939 F.3d 1216, 1232 (11th Cir. 2019) (citation, internal alteration, and internal
quotation marks omitted).
427 Ocasio v. United States, 136 S. Ct. 1423, 1429-30 (2016).
428 As explained previously, some statutes that separately proscribe conspiracies to violate their provisions do not
require an overt act and thus may give rise to liability based on agreement alone, with the requisite mental state. See
supra notes 48-50 and accompanying text.
429 United States v. $11,500.00 in U.S. Currency, 869 F.3d 1062, 1072 (9th Cir. 2017).
430 United States v. Bradley, 917 F.3d 493, 505 (6th Cir. 2019); Doyle, Conspiracy, supra note 48, at 8 & n.63.
431 United States v. Vallone, 752 F.3d 690, 697-98 (7th Cir. 2014).
432 United States v. George, 886 F.3d 31, 41 (1st Cir. 2018).
433 United States v. Henry, 984 F.3d 1343, 1355 (9th Cir. 2021).
434 18 U.S.C. § 371.
435 E.g., id. § 2339A(a) (prohibiting attempt to provide material support or resources to terrorists).
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qualifying as a substantial step toward completion of [that] goal.”436 A “substantial step” requires
more than mere preparation to commit an offense, and determining “the point at which
preliminary action becomes a substantial step is fact specific” and may depend on the particular
offense at issue.437 A charge of attempt does not require completion of the target crime,438 but
unlike conspiracy, if the target crime is committed, one may not be punished separately for both
the completed crime and attempt to commit it.439 Penalties for attempt depend on the particular
statute in which attempt is proscribed, though generally, federal attempt crimes carry the same
penalties as the substantive offense.440
Solicitation
18 U.S.C. § 373 prohibits solicitation to commit a “crime of violence”—in other words, efforts to
induce another to commit such a crime “under circumstances strongly corroborative” of an intent
that the other should do so.441 A “crime of violence” is defined as a federal felony “that has as an
element the use, attempted use, or threatened use of physical force against property or against the
person of another.”442 “Evidence sufficient to strongly corroborate a defendant’s intent includes,
but is not limited to, evidence showing that the defendant: (1) offered or promised payment or
some other benefit to the person solicited; (2) threatened to punish or harm the solicitee for failing
to commit the offense; (3) repeatedly solicited the commission of the offense or expressly stated
his seriousness; (4) knew or believed that the person solicited had previously committed a similar
offense; or (5) acquired weapons, tools or information, or made other preparations, suited for use
by the solicitee.”443
Although a full explication of the process for determining whether an offense is a “crime of
violence” based on the statutory definition in Section 373 is beyond the scope of this report,
several offenses that address or can apply to domestic terrorism undoubtedly qualify.444 As such,
Section 373 may be used as a separate vehicle to charge efforts to recruit others to commit such
offenses as described in other sections of this report, provided the requisite intent and
corroborative circumstances are present.

436 United States v. Resendiz-Ponce, 549 U.S. 102, 107 (2007); United States v. Vinton, 946 F.3d 847, 852 (6th Cir.
2020).
437 Doyle, Attempt, supra note 420, at 5; see United States v. Farhane, 634 F.3d 127, 147, 148 (2d Cir. 2011)
(discussing substantial step requirement in context of attempt to provide material support to foreign terrorist
organization in violation of 18 U.S.C. § 2339B).
438 United States v. Nguyen, 829 F.3d 907, 917 (8th Cir. 2017).
439 United States v. Rivera-Relle, 333 F.3d 914, 921 n.11 (9th Cir. 2003).
440 Doyle, Attempt, supra note 420, at 12.
441 18 U.S.C. § 373(a). As with attempt, one may not be guilty of both solicitation and the completed crime that was
solicited. United States v. Korab, 893 F.2d 212, 213 (9th Cir. 1989).
442 18 U.S.C. § 373(a).
443 United States v. Dvorkin, 799 F.3d 867, 879 (7th Cir. 2015). By statute, preventing commission of the crime
solicited “under circumstances manifesting a voluntary and complete renunciation of” one’s criminal intent is an
affirmative defense to prosecution. 18 U.S.C. § 373(b). That the person solicited could not be convicted of the crime
due to legal incapacity is no defense, however. Id. § 373(c).
444 E.g., United States v. Doggart, 947 F.3d 879, 883 (6th Cir. 2020) (involving solicitation to commit federal arson
under 18 U.S.C. § 844(i)).
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Accomplice Liability
18 U.S.C. § 2 establishes that accomplices or “aiders and abettors” of federal crimes are guilty to
the same extent as those who directly carry them out.445 Section 2 does not define a separate
crime, but rather delineates “alternative means of incurring criminal liability” for an underlying
offense.446 The statute actually comprises two forms of accomplice liability with substantial
overlap. Section 2(a) speaks of one who “aids, abets, counsels, commands, induces or procures”
the commission of a federal crime.447 Aiding and abetting requires that one associate himself with
an effort to carry out a crime, “participate[] in it as in something he wishe[s] to bring about, and
[seek] by his actions to make it succeed.”448 Something more is required than merely being
present at the scene of a crime with knowledge that it will be carried out,449 but a defendant’s
participation need not advance every element of the aided crime.450 That said, the accomplice
must intend that the underlying offense be committed, which requires that he be aware in advance
of its scope.451 It is also a prerequisite that the crime then be accomplished.452
Section 2(b) provides that one who “willfully causes an act to be done which if directly
performed by him or another would be” a federal offense is “punishable as a principal” for the
completed crime.453 Although it appears that much of the same ground is covered by the language
of 2(a) regarding one who “commands, induces or procures” commission of a federal crime,
Congress enacted Section 2(b) to clarify that accomplice liability applies “to defendants who
work through either culpable or innocent intermediaries.”454 To violate the provision, one must
intentionally cause another to act in violation of the underlying statute, with the intent required
for such a violation.455
As noted above, Section 2 does not establish distinct criminal offenses; it provides means for
charging those who aid in federal crimes with the aided crimes themselves. As such, one may be
prosecuted for violations of the federal statutes related to domestic terrorism that are discussed in
other sections of this report not only where one personally and individually carries out the
prohibited acts, but also where one acts as an accomplice under Section 2 to assist in commission
of the underlying offenses by others.

445 18 U.S.C. § 2(a).
446 Doyle, Accomplices, supra note 423, at 1.
447 18 U.S.C. § 2(a).
448 United States v. Tanco-Baez, 942 F.3d 7, 27 (1st Cir. 2019) (quoting United States v. Luciano-Mosquera, 63 F.3d
1142, 1149-50 (1st Cir. 1995)).
449 Id.
450 United States v. De Nieto, 922 F.3d 669, 677-78 (5th Cir. 2019).
451 Rosemond v. United States, 572 U.S. 65, 77-78 (2014).
452 United States v. Freed, 921 F.3d 716, 721 (7th Cir. 2019) ("Additionally, it is axiomatic that one cannot aid and abet
a crime unless a crime was actually committed."). 18 U.S.C. § 3 separately punishes one who gives assistance after a
crime has occurred as an “accessory after the fact.” See 18 U.S.C. § 3 (“Whoever, knowing that an offense against the
United States has been committed, receives, relieves, comforts or assists the offender in order to hinder or prevent his
apprehension, trial or punishment, is an accessory after the fact.”).
453 18 U.S.C. § 2(b).
454 Doyle, Accomplices, supra note 423, at 7; see United States v. Singh, 924 F.3d 1030, 1050 (9th Cir. 2019), vacated
on other grounds by Azano Matsura v. United States, 140 S. Ct. 991 (2020) (mem. op.) (“Section 2(b) is intended to
impose criminal liability on one who causes an intermediary to commit a criminal act, even though the intermediary
who performed the act has no criminal intent and hence is innocent of the substantive crime charged.”).
455 See United States v. Gumbs, 283 F.3d 128, 382-83 (3d Cir. 2002) (holding that defendant must possess mens rea
required by underlying criminal statute that he causes intermediary to violate and the intent to cause the act prohibited).
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Domestic Terrorism at Sentencing
Beyond the federal criminal offenses described above that can apply to domestic terrorism,
conduct defined or related to domestic terrorism may be relevant to sentencing those convicted of
federal crimes in at least two ways. First, some federal criminal statutes provide for heightened
statutory maximum sentences if a violation of the statute involves or relates to terrorism.456
Second, conduct related to terrorism can factor in to calculating the sentence range recommended
by the U.S. Sentencing Guidelines.457
Statutes with Terrorism-Related Sentence Enhancement Provisions
Several federal statutes that do not, in their ordinary context, relate to terrorism nevertheless
provide for increased penalties if terrorism is involved.458
1. 18 U.S.C. § 1001 prohibits knowingly and willfully making or using materially false
statements or documents “in any matter within the jurisdiction of the executive, legislative, or
judicial branch” of the federal government, punishable by fine and/or imprisonment for up to
five years.459 However, “if the offense involves international or domestic terrorism” as
defined in 18 U.S.C. § 2331, the statutory maximum sentence increases to eight years.460
2. Similarly, 18 U.S.C. § 1505 proscribes intentionally influencing, obstructing, or impeding (or
endeavoring to do any of the three) congressional or federal administrative proceedings,
punishable by fine and/or imprisonment for up to five years.461 If a Section 1505 offense
involves international or domestic terrorism, however, imprisonment for up to eight years is
authorized.462

456 E.g., 18 U.S.C. § 1001(a) (increasing sentence for making false statements to the government from 5 to 8 years “if
the offense involves international or domestic terrorism”). A connection to terrorism may have other statutory effects
beyond sentence enhancement—for instance, whether the defendant has allegedly committed a federal crime of
terrorism under 18 U.S.C. § 2332b factors into the judicial decision as to whether he or she should be released or
detained pending trial. See 18 U.S.C. § 3142(e)(3), (g)(1) (providing that probable cause to believe the person
committed “an offense under . . . 2332b” establishes rebuttable presumption that detention should be ordered and
requiring consideration of “the nature and circumstances of the offense charged, including whether the offense is . . . a
Federal crime of terrorism”).
457 See infra, § “Terrorism under the U.S. Sentencing Guidelines.”
458 Though not a sentence enhancement provision per se, one federal statute not discussed elsewhere in this report
incorporates domestic terrorism as an element in a limited context. Specifically, 18 U.S.C. § 226 prohibits bribery, i.e.,
corruptly giving, offering, or promising anything of value to any public or private person, with intent to commit
international or domestic terrorism (as defined in 18 U.S.C. § 2331) and to induce unlawful action or further fraud
affecting a secure seaport area. 18 U.S.C. § 226(a)(1). The statute also prohibits receipt of bribes in return for being
influenced in the performance of any official act affecting a secure seaport area, if the bribe recipient knows the
influence will be used “to commit, or plan to commit, international or domestic terrorism.” Id. § 226(a)(2). Violations
are punishable by fines and/or up to fifteen years in prison. Id. Other provisions may also increase statutory penalties
specifically for foreign-focused conduct related to terrorism—for instance, 21 U.S.C. § 960a addresses narco-terrorism
and requires imprisonment for at least twice the minimum required for controlled substance distribution offenses, up to
life in prison, if the conduct would be punishable as one of those offenses if committed within the jurisdiction of the
United States and the offender knows or intends to provide anything of pecuniary value to a person or organization
engaging in terrorist activity or terrorism, among other things. 21 U.S.C. § 960a(a).
459 18 U.S.C. § 1001(a).
460 Id.
461 Id. § 1505. The statute also separately addresses interference with DOJ civil investigative demands issued in
antitrust cases. Id.
462 Id. For more information on Section 1001 false statements and Section 1505 obstruction generally, see CRS Report
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3. 18 U.S.C. § 1028 addresses identity theft, i.e., the production, possession, and distribution of
fraudulent or unauthorized identification documents, authentication features, and means of
identification of other persons.463 In essence, the offenses in Section 1028 relate to the
unlawful use of false or unauthorized documents or information used for identification
purposes, such as drivers’ licenses, social security numbers, or unique biometric identifiers, to
name a few.464 Authorized sentences under Section 1028 depend on the provision violated and
certain other factors and, for violations unrelated to terrorism, can range from up to one year
to up to twenty years’ imprisonment.465 For offenses “committed to facilitate an act of
domestic terrorism” or international terrorism, fines and/or imprisonment for up to thirty
years are authorized.466
4. 18 U.S.C. § 1028A prohibits aggravated identity theft, i.e., knowingly and without lawful
authority transferring, possessing, or using a “means of identification of another person”
during and in relation to specifically enumerated federal felonies such as making false
statements to acquire a firearm or embezzling public money.467 Violations are punished by an
additional term of imprisonment of two years on top of the punishment for the underlying
felony.468 Separately, however, the statute proscribes the same conduct, involving means of
identification of another person or false identification documents,469 during and in relation to
felony violations of the statutes listed as “federal crimes of terrorism” in 18 U.S.C.
§ 2332b.470 In this latter circumstance, an additional five years of imprisonment is added to
the punishment for the underlying offense.471
5. A significant number of federal statutes make murder in particular contexts a capital
offense.472 However, the death penalty may be imposed only if, among other things,473 at least
one statutory aggravating circumstance is proven beyond a reasonable doubt at a subsequent
sentencing hearing.474 18 U.S.C. § 3592 lists the mitigating and aggravating factors that are to

RL34303, Obstruction of Justice: An Overview of Some of the Federal Statutes That Prohibit Interference with
Judicial, Executive, or Legislative Activities, by Charles Doyle.
463 The statute proscribes eight separate categories of conduct related to the unlawful production, possession, transfer,
or trafficking of authentication features, identification documents, means of identification of others, and document-
making implements. 18 U.S.C. § 1028(a)(1)-(8). At least one of a number of specific jurisdictional prerequisites must
be met for the offenses in Section 1028 to apply. See id. § 1028(c).
464 See id. § 1028(d)(1)-(8) (defining terms “authentication feature,” “identification document,” and “means of
identification,” among others).
465 Id. § 1028(b)(1)-(3), (6). Fines are also authorized. Id.
466 Id. § 1028(b)(4).
467 Id. § 1028A(a)(1), (c). A “means of identification” is defined in Section 1028 as “any name or number that may be
used, alone or in conjunction with any other information, to identify a specific individual,” such as a social security
number, date of birth, or passport number, among other things. Id. § 1028(d)(7).
468 Id. § 1028A(a)(1).
469 An “identification document” is defined in Section 1028 as “a document made or issued by or under the authority”
of a domestic or foreign government or certain other entities “which, when completed with information concerning a
particular individual, is of a type intended or commonly accepted for the purpose of identification of individuals.” Id.
§ 1028(d)(3).
470 See id. § 2332b(g)(5)(B).
471 Id. § 1028A(a)(2).
472 See CRS Report R42095, Federal Capital Offenses: An Overview of Substantive and Procedural Law, by Charles
Doyle, at 13 (“Murder is a capital offense under more than 50 federal statutes.”).
473 At least one of several mental-state requirements also must be met. 18 U.S.C. § 3591(a)(2).
474 See id. § 3593(c)-(e).
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be considered in determining whether a sentence of death is justified. Among the aggravating
factors for homicide is that death occurred during commission, attempted commission, or
immediate flight from commission of a number of other federal offenses, the majority of
which are included on the list of “federal crimes of terrorism” in 18 U.S.C. § 2332b.475 For
instance, one of the offenses through which the aggravating factor can apply is the Chapter
113B offense involving the use of WMDs, which can apply to cases meeting the statutory
definition of domestic terrorism.476 Additionally, a separate aggravating factor for homicide is
that the defendant “committed the offense after substantial planning and premeditation to . . .
commit an act of terrorism.”477 Though “act of terrorism” is undefined in Section 3592, it
appears that the aggravating factor can apply to domestic acts.478
Terrorism under the U.S. Sentencing Guidelines
As described elsewhere, federal criminal offenses that may be applied to domestic terrorism are
subject to varying statutory maximum penalties. The sentence actually imposed on a defendant
below, or up to, a particular statutory maximum is also influenced by the U.S. Sentencing
Guidelines.479 A court must begin the sentencing process by correctly calculating the sentence
range recommended by the Guidelines for the offense.480 That range is consulted, along with
other statutory factors, to arrive at a sentence that is “reasonable.”481 Sentencing ranges under the
Guidelines are calculated based on a defendant’s “Offense Level” and “Criminal History
Category.”482 In turn, the “Offense Level” is determined by reference to a “base offense level” set
for the particular offense, as listed in Chapter Two of the Guidelines, that is adjusted up or down
in light of characteristics specific to the offense as committed.483 “Adjustments” found in Chapter
Three of the Guidelines based on victim, the defendant’s role in the offense, and certain other
circumstances may then be applied to further modify the offense level, criminal history category,
or both.484
Section 3A1.4 of the Guidelines’ Chapter Three adjustments specifically addresses terrorism. The
adjustment provides that for a felony offense “that involved, or was intended to promote, a
federal crime of terrorism,” the offense level must be increased substantially—specifically, by
twelve levels or to Level 32, whichever is higher.485 Additionally, the defendant’s criminal history
category is automatically increased to the highest category—Category VI.486 An application note

475 Id. § 3592(c)(1).
476 See id.; supra notes 111-115 and accompanying text.
477 18 U.S.C. § 3592(c)(9).
478 See United States v. Tsarnaev, 968 F.3d 24, 81 (1st Cir. 2020) (addressing terrorism aggravating factor in
connection with sentencing of one of the men involved in Boston marathon bombing).
479 See generally CRS Report R41696, How the Federal Sentencing Guidelines Work: An Overview, by Charles Doyle.
480 Gall v. United States, 552 U.S. 38, 49 (2007).
481 Id. at 46.
482 U.S. SENT’G GUIDELINES MANUAL § 1B1.1 (U.S. SENT’G COMM’N 2018).
483 Id. Depending on the offense, the offense level may be increased, before further adjustment under Chapter Three of
the Guidelines, based on the relationship of the offense to terrorism. For instance, the guideline for obstruction of
justice provides a base offense level of fourteen, but for convictions under 18 U.S.C. § 1001 or § 1505 that relate to
international or domestic terrorism, an increase of twelve levels is required. Id. § 2J1.2; see also id. § 2X1.1 (attempt,
solicitation, or conspiracy not covered by a specific offense guideline); id. § 2X3.1 (accessory after the fact).
484 Id. § 1B1.1.
485 Id. § 3A1.4(a).
486 Id. § 3A1.4(b).
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specifies that the term “federal crime of terrorism” has the meaning given the term in 18 U.S.C.
§ 2332b(g)(5)—i.e., the term refers to a specifically enumerated list of over fifty federal offenses,
many of which may apply to domestic terrorism, that are “calculated to influence or affect the
conduct of government by intimidation or coercion, or to retaliate against government
conduct.”487 A separate application note effectively expands this definition for purposes of
Guidelines sentencing, in two respects: if either (1) the offense meets the “calculated to influence
or affect . . . or to retaliate against government” component of the “federal crime of terrorism”
definition but involved or was intended to promote a federal offense not listed in Section
2332b(g)(5), or (2) the offense involved or was intended to promote a federal offense listed in
Section 2332b(g)(5) but sought to “intimidate or coerce a civilian population” rather than being
targeted at the government, the court may still impose a sentence up to the top of the range that
would result if the terrorism adjustment applied.488
Given the language that an offense must have “involved” or been “intended to promote” a federal
crime of terrorism, federal courts have treated the adjustment as establishing two distinct avenues
for application: first, the adjustment can apply if the offense “involves” a federal crime of
terrorism in the sense that it includes an offense listed in Section 2332b(g)(5) that meets the
“calculated to influence or affect . . . or to retaliate against government” requirement;489 second,
the adjustment can apply if the offense is “intended to promote” a federal crime of terrorism,
which does not require that the underlying offense be included in Section 2332b(g)(5) but instead
encompasses situations where the defendant has as a purpose, in committing the underlying
criminal conduct, the promotion of a crime of terrorism, i.e., “to encourage, further, or bring
about” such a crime.490 Under the “intended to promote” prong, the sentencing court must
“identify which enumerated ‘Federal crime of terrorism’ the defendant intended to promote” and
“satisfy the elements of § 2332b(g)(5)(A),” i.e., find that the promoted crime was “calculated to
influence or affect . . . or to retaliate against government,” based on facts in the record.491
Courts have treated the prerequisite that a “federal crime of terrorism” be “calculated to influence
or affect . . . or to retaliate against government” as establishing a specific intent requirement.492
This intent requirement is distinct from motive, as the focus is not “on the defendant but on his

487 Id. § 3A1.4 cmt. 1; 18 U.S.C. § 2332b(g)(5). For further discussion of federal crimes of terrorism, see supra notes
27-33 and accompanying text.
488 U.S. SENT’G GUIDELINES MANUAL § 3A1.4 cmt. 4 (U.S. SENT’G COMM’N 2018) (emphasis added); see, e.g., United
States v. Jordi, 418 F.3d 1212, 1217 (11th Cir. 2005) (recognizing departure was authorized in case involving plans to
bomb abortion clinics, as conduct involved an offense enumerated in Section 2332b(g)(5)(B) and lower court found the
defendant sought to intimidate or coerce civilians).
489 See United States v. Fidse, 862 F.3d 516, 522 (5th Cir. 2017). The “involves” prong may be met if the court finds
for purposes of sentencing under the Guidelines that a listed federal crime of terrorism was committed. Id.
490 United States v. Awan, 607 F.3d 306, 314 (2d Cir. 2010). A Section 3A1.4 application note reinforces the point by
making clear that “harboring or concealing a terrorist who committed a federal crime of terrorism” in violation of 18
U.S.C. § 2339 or § 2339A, both of which are listed in Section 2332b(g)(5)(B), meets the Section 3A1.4 criteria, as does
“obstructing an investigation of a federal crime of terrorism” despite the fact that obstruction would not necessarily
directly involve a Section 2332b(g)(5)(B) offense. U.S. SENT’G GUIDELINES MANUAL § 3A1.4 cmt. 2 (U.S. SENT’G
COMM’N 2018).
491 United States v. Graham, 275 F.3d 490, 517 (6th Cir. 2001).
492 E.g., United States v. Alhaggagi, 978 F.3d 693, 699-700 (9th Cir. 2020) (“The parties agree, consistent with the
district court’s decision and those of our sister circuits that have addressed the issue, that § 2332b(g)(5)(A) imposes a
specific intent requirement.”); United States v. Ansberry, 976 F.3d 1108, 1127 (10th Cir. 2020); United States v.
Hassan, 742 F.3d 104, 148-49 (4th Cir. 2014).
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‘offense,’ asking whether it was calculated, i.e., planned—for whatever reason or motive—to
achieve the stated object.”493
Considerations for Congress
Both current law and possible future domestic terrorism legislation may give rise to several
practical and constitutional considerations for Congress. First is the question of whether there is a
gap in current laws applicable to foreign and domestic terrorism, including what policy arguments
exist for and against a new domestic terrorism law. Next, several potential constitutional issues
related to congressional power and the First and Fourth Amendments are relevant to existing, and
possible new, laws regarding domestic terrorism. This section addresses each consideration in
turn and concludes with a summary of recent domestic terrorism legislation in the 116th and
117th Congresses.
Is there a Gap in Current Law?
This section analyzes whether there is a disparity in federal law addressing domestic and foreign
terrorism in two respects: (1) the types of offenses available to prosecute terrorism and sentences
imposed for those offenses; (2) the investigatory tools available to law enforcement.494
Differences in Offenses and Sentences
Federal law defines both domestic terrorism and international terrorism.495 There is, however, no
specific federal crime of domestic terrorism. Moreover, as discussed above, the way federal law
treats each type of terrorism differs to some degree.496 While some of the offenses in Chapter
113B of Title 18 of the U.S. Code can apply to both domestic and international terrorism,497 other
statutes in that chapter apply only to conduct that takes place outside the United States498 or has
an international component.499 Yet, a number of other existing federal criminal laws could
potentially apply to acts of domestic terrorism.500 At least one commentator has observed that
18 U.S.C. § 2339A—which prohibits material support of terrorism—explicitly lists more than

493 Awan, 607 F.3d at 317; Alhaggagi, 978 F.3d at 700.
494 For additional discussion of these and other issues, see Doyle, Domestic Terrorism, supra note 5.
495 See 18 U.S.C. § 2331(1) and (5) (defining international terrorism and domestic terrorism, respectively).
496 Compare § “Federal Criminal Terrorism Laws” with § “Other Federal Criminal Laws Applicable to Domestic
Terrorism,” both supra.
497 E.g., 18 U.S.C. §§ 2332a (prohibiting the use of weapons of mass destruction), 2332g (prohibiting the use of missile
systems designed to destroy aircraft), 2339A (prohibiting material support to terrorists in connection with enumerated
offenses).
498 E.g., 18 U.S.C. §§ 2332 (prohibiting homicide and other violent acts against U.S. nationals outside the United
States), 2332d (prohibiting financial transactions with foreign governments that support international terrorism), 2339D
(prohibiting the receipt of “military-type training” from a foreign terrorist organization).
499 E.g., 18 U.S.C. § 2332b. As discussed above, see supra, § “Terrorism Transcending National Boundaries: 18 U.S.C.
§ 2332b,” it is unclear the extent to which § 2332b—which applies to acts of terrorism transcending national
boundaries—could apply to domestic terrorism. In at least one case, a co-conspirator’s online exchange of information
with a person outside the United States was enough to constitute conduct transcending national boundaries for the
purposes of § 2332b. United States v. Wright, 285 F. Supp. 3d 443, 459-60 (D. Mass 2018), aff’d, 937 F.3d 8 (1st Cir.
2019). It is less clear whether § 2332b could be used to prosecute a crime with a more tenuous international connection.
500 See “Other Federal Criminal Laws Applicable to Domestic Terrorism” above for a more detailed discussion of these
laws.
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fifty “federal crimes of terrorism” that could be applicable to either domestic or international
terrorism.501
At the same time, these and other federal crimes are limited; they do not—and cannot—cover all
conceivable criminal conduct. The Constitution limits the types of laws that Congress may
pass.502 Likewise, the federal courts are constrained by the Constitution and by statute in the types
of cases they may hear.503 As a result, it is possible that some individuals engaging in conduct that
satisfies Section 2331(5)’s definition of domestic terrorism could evade federal prosecution.504
For example, while 18 U.S.C. § 1114 prohibits killing officers and employees of the United
States,505 federal law does not—and cannot—prohibit murder generally.506 Thus, an individual
likely could be charged under Section 2339A for providing material support for the killing of a
federal officer or employee.507 In contrast, an individual could not be charged under
Section 2339A for providing material support for the killing of a state employee unless the
offense fell within one of the other listed statutes in Section 2339A. Conversely, though it is also
possible that some conduct meeting the definition of international terrorism could evade federal
prosecution, there are additional laws applicable specifically to international terrorism that have
no domestic counterparts, such as the Section 2339B prohibition on providing material support or
resources to designated foreign terrorist organizations.508 Some commentators have argued that
the lack of domestic counterparts to these laws constitutes a gap between domestic and
international anti-terrorism laws.509
In addition to this potential gap in how the federal government may prosecute domestic and
international terrorism, some have asserted that there is a disparity in the types of sentences
judges may impose on those convicted under federal law of international and domestic terrorism.
While some existing federal criminal statutes provide for heightened maximum sentences if a
violation of the statute involves or relates to terrorism, these heightened sentences are not

501 See GERMAN & ROBINSON, supra note 21, at 5-7 (discussing the domestic application of the predicate offenses listed
in 18 U.S.C. § 2339A). Some of these potential offenses include violence at international airports, 18 U.S.C. § 37,
killing any person with a firearm or dangerous weapon in federal facilities, id. § 930(c), killing or attempting to kill any
officer or employee of the United States, id. § 1114, and hostage taking, id. § 1203.
502 See infra, § “Constitutional Issues.”
503 See, e.g., Kokkonen v. Guardian Life Ins. Co. of Am., 511 U.S. 375, 377 (1994) (“Federal courts are courts of
limited jurisdiction. They possess only that power authorized by the Constitution and statute . . . which is not to be
expanded by judicial decree . . . . It is to be presumed that a cause lies outside of this limited jurisdiction.” (internal
citations omitted)).
504 These individuals could still be subject to prosecution in state courts. See, e.g., Engle v. Isaac, 456 U.S. 107, 128
(1982) (“The States possess primary authority for defining and enforcing the criminal law.”).
505 18 U.S.C. § 1114.
506 Torres v. Lynch, 136 S. Ct. 1619, 1624 (2016) (reiterating that “‘Congress cannot punish felonies generally’”
(quoting Cohens v. Virginia, 19 U.S. (6 Wheat.) 264, 428 (1821)). Rather, Congress “may enact only those criminal
laws that are connected to one of its constitutionally enumerated powers, such as the authority to regulate interstate
commerce” Id. That said, murder and homicide are federally proscribed in other statutes with specific jurisdictional
limitations. E.g., 18 U.S.C. § 1111 (establishing penalties for murder in the special maritime and territorial jurisdiction
of the United States).
507 18 U.S.C. § 2339A(a) (recognizing 18 U.S.C. § 1114 as a crime subject to the material support prohibition).
508 18 U.S.C. § 2339B.
509 E.g., Sinnar, supra note 4, at 1334-35 (“Material support to terrorism laws . . . do not apply equally to domestic and
international terrorism.”). But see GERMAN & ROBINSON, supra note 21, at 9 (arguing that the anti-terrorism laws “that
apply domestically provide ample authority to prosecute domestic terrorism cases” and “federal law also provides
many other appropriate alternatives.”).
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available for all crimes.510 Likewise, although the U.S. Sentencing Guidelines include provisions
that take terrorism into account when calculating the sentencing range for an offense,511 these
provisions apply only to conduct that relates to one of the “federal crimes of terrorism”
enumerated in 18 U.S.C. § 2332b(g)(5).512 Thus, whether an individual may be subject to
increased penalties for terrorism depends on the statute under which the individual is convicted.
In light of the possible gap in the laws available to charge domestic and international terrorism,
some commentators argue that the terrorism-related sentence enhancements disproportionately
apply to individuals convicted of international terrorism.513 This potential sentencing gap might
also result from prosecutorial discretion; some commentators argue that prosecutors are less
likely to charge acts of domestic terrorism under available anti-terrorism laws, which could result
in fewer terrorism-related sentencing enhancements in domestic cases.514
Differences in Intelligence Gathering
In the surveillance and intelligence-gathering context, federal law again provides different tools
for law enforcement depending on whether an act of terrorism is domestic or international. In
domestic cases, government investigations must comply with specific constitutional and statutory
limits, including the Fourth Amendment’s right to be secure “against unreasonable searches and
seizures.”515 Under that right, where an individual has a reasonable expectation of privacy or there
is a physical intrusion into a constitutionally protected area, the government generally must show
probable cause and obtain a warrant before conducting a search.516
It is less clear whether or to what extent the Fourth Amendment applies to foreign surveillance;
the Supreme Court has not addressed that issue and, in at least one case, has declined to do so.517
Absent clear constitutional guidance, Congress has authorized several collection and surveillance

510 E.g., 18 U.S.C. § 1001(a) (providing an increased penalty for making false statements to the government in cases
involving domestic or international terrorism). For a more detailed discussion of statutes that include heightened
maximum sentences in cases involving terrorism, see supra, § “Statutes with Terrorism-Related Sentence Enhancement
Provisions.”
511 U.S. SENT’G GUIDELINES MANUAL § 3A1.4 (U.S. SENT’G COMM’N 2018). For a more detailed discussion of the U.S.
Sentencing Guidelines in terrorism-related cases, see supra § “Terrorism under the U.S. Sentencing Guidelines.”
512 U.S. SENT’G GUIDELINES MANUAL § 3A1.4(a), cmt. 1 (U.S. SENT’G COMM’N 2018).
513 See Sinnar, supra note 4, at 1358 (“At the sentencing stage, the uneven coverage of federal terrorism law means that
a severe federal sentencing enhancement disproportionately applies to cases with an international nexus.”).
514 E.g., Michael German, Why New Laws Aren’t Needed to Take Domestic Terrorism More Seriously, JUST SECURITY
(Dec. 14, 2018), https://www.justsecurity.org/61876/laws-needed-domestic-terrorism/ (arguing that “it is often the case
that it is easier to charge domestic terrorists using a variety of other federal laws.”); Lisa Daniels, Prosecuting
Terrorism in State Court, LAWFARE (Oct. 26, 2016, 11:33 am), https://www.lawfareblog.com/prosecuting-terrorism-
state-court (“State terrorism prosecutions are extremely rare, despite the fact that at least 33 states passed sweeping
anti-terrorism legislation in the wake of 9/11.”).
515 See, e.g., U.S. CONST. amend. IV. The Fourth Amendment’s limits on domestic surveillance are discussed below in
more detail. See infra, § “Fourth Amendment.”
516 E.g., Smith v. Maryland, 442 U.S. 735, 740 (1979) (holding that “the application of the Fourth Amendment depends
on whether the person invoking its protection can claim a ‘justifiable,’ a ‘reasonable,’ or a ‘legitimate expectation of
privacy’ that has been invaded by government action”); United States v. Jones, 565 U.S. 400, 506-07 (2012)
(reiterating that the Fourth Amendment safeguards against physical intrusions into constitutionally protected areas).
517 See Carpenter v. United States, 138 S. Ct. 2206, 2220 (2018) (holding that obtaining an individual’s cell phone
location information was a search subject to the Fourth Amendment but declining to “consider other collection
techniques involving foreign affairs or national security”). At least one lower court, however, has held that warrants are
not always required for surveillance targeting “foreign powers or agents of foreign powers reasonably believed to be
located outside the United States.” In re Directives Pursuant to Section 105B of Foreign Intelligence Surveillance Act,
551 F.3d 1004, 1012 (FISA Ct. Rev. 2008).
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procedures for foreign affairs and national security purposes that do not follow the Fourth
Amendment warrant process. For example, the Foreign Intelligence Surveillance Act of 1978
(FISA),518 as amended, provides a powerful set of tools to collect foreign intelligence
information519 through electronic surveillance,520 physical searches,521 access to specified business
records,522 and other means.523 FISA requires a nexus to a foreign power or agent of a foreign
power; it thus cannot be used to conduct purely domestic investigations.524 Moreover, in contrast
to the probable cause standard applicable to domestic surveillance (which requires investigators
seeking a warrant to demonstrate “a fair probability” that contraband or evidence of crime will be
found in a particular place525), investigators seeking a court order authorizing electronic
surveillance under FISA need not assert that the evidence sought relates to a crime, only that it
satisfies FISA’s foreign nexus requirement.526
Despite these differences, some commentators argue that, outside of FISA, federal investigative
tools “do not distinguish as sharply between domestic and international terrorism.”527 Similarly,
other scholars argue that “a multitude of existing laws already allow the federal government to

518 Foreign Intelligence Surveillance Act of 1978, P.L. 95-511, 92 Stat. 1783, codified as amended at 50 U.S.C. ch. 36.
Congress passed several major amendments to FISA in the wake of the September 11, 2001, terrorist attacks, including
the USA PATRIOT Act, which was designed, in part, to “provid[e] enhanced investigative tools” to “assist in the
prevention of future terrorist activities and the preliminary acts and crimes which further such activities.” Uniting and
Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism (USA
PATRIOT) Act of 2001, P.L. 107-56, tit. II, 115 Stat. 272, 278; H.Rept. 107-231, pt. 1, at 41. For information on these
amendments, including several authorities that recently lapsed, see CRS Report R40138, Origins and Impact of the
Foreign Intelligence Surveillance Act (FISA) Provisions That Expired on March 15, 2020, by Edward C. Liu.
519 FISA defines foreign intelligence information as:
(1) information that relates to, and if concerning a United States person is necessary to, the ability
of the United States to protect itself against—
(A) actual or potential attack or other grave hostile acts of a foreign power or an agent of a
foreign power;
(B) sabotage, international terrorism, or the international proliferation of weapons of mass
destruction by a foreign power or an agent of a foreign power; or
(C) clandestine intelligence activities by an intelligence service or network of a foreign power
or by an agent of a foreign power; or
(2) information with respect to a foreign power or foreign territory that relates to, and if concerning
a United States person is necessary to—
(A) the national defense or the security of the United States; or
(B) the conduct of the foreign affairs of the United States.
50 U.S.C. § 1801(e).
520 See id. §§ 1801-12.
521 See id. §§ 1821-29.
522 See id. §§ 1861-62.
523 See id. §§ 1841-46.
524 See id. § 1801(b) (defining agent of a foreign power as “any person other than a United States person” who engages
in specified activities), (e) (defining foreign intelligence information).
525 Illinois v. Gates, 462 U.S. 213, 238 (1983).
526 50 U.S.C. § 1804(a)(3) (applications for an order approving electronic surveillance must include, among other
requirements, ”a statement of facts and circumstances relied upon by the applicant to justify his belief that” a foreign
nexus exists).
527 Sinnar, supra note 4, at 1350 (citing terrorist watch lists and Department of Justice investigation guidelines as
examples).
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formally investigate [domestic] attacks as domestic terrorism, even if those crimes are eventually
prosecuted as murders, hate crimes or something else.”528
Need for a Separate Domestic Terrorism Law
A number of scholars argue that the distinction between domestic terrorism and international
terrorism in current law results in disproportionate prosecution and sentencing of international
terrorism offenses.529 These scholars disagree, however, on whether a new domestic terrorism law
is necessary to cure this disparity.
Some commentators opposed to a new domestic terrorism law argue that “pleas for a new
domestic terrorism statute are misplaced,” as the Department of Justice “has robust authority to
prosecute domestic terrorism . . . [but] simply chooses not to prioritize these cases as a matter of
policy and practice.”530 Likewise, other scholars argue that “calls to ‘ratchet up’ [domestic]
terrorism law ignore the potential liberty and equality costs of doing so,” including “concerns
over free speech and privacy.”531 In addition, several scholars have voiced concerns that
“increasing federal authority will, most likely, only lead to additional disparities affecting
minorities and disfavored political groups within the United States.”532
In contrast, some commentators argue that, although existing “state law can ensure just
punishment for domestic terrorism,” the creation of a separate federal domestic terrorism offense
would “recognize domestic terrorism for what it is: the moral equivalent of international
terrorism.”533 Similarly, some argue that creating a federal domestic terrorism offense “would
lead federal law enforcement to devote more resources to investigating” acts of domestic terror534
and “counter the widespread but incorrect notion that the federal government does not care about
domestic terrorism.”535

528 Harsha Panduranga & Faiza Patel, “Domestic Terrorism” Bills Create More Problems Than They Solve, JUST
SECURITY (Aug. 28, 2019), https://www.justsecurity.org/65998/domestic-terrorism-bills-create-more-problems-than-
they-solve/.
529 See Sinnar, supra note 4. at 1364 (“The domestic-international legal binary affects how government officials
understand and characterize political violence . . . . For example, government officials say they hesitate to describe
domestic cases as terrorism where explicit federal terrorism charges are not available.”); Francesca Laguardia,
Considering a Domestic Terrorism Statute and Its Alternatives, 114 N.W. U. L. REV. 1061, 1075 (2020) (“The current
statutory scheme limits prosecution of modern terrorism, but then broadens it again in international (but not domestic)
cases.”); Courtney Kurz, Closing the Gap: Eliminating the Distinction Between Domestic and International Terrorism
Under Federal Law, 93 TEMP. L. REV. 115, 116 (2020) (“Under federal law, acts of international terrorism are currently
treated more seriously and punished more harshly than similar acts of a domestic nature.”).
530 GERMAN & ROBINSON, supra note 21, at 5.
531 Sinnar, supra note 4, at 1399-4000.
532 Laguardia, supra note 529, at 1077.
533 Mary B. McCord, Criminal Law Should Treat Domestic Terrorism as the Moral Equivalent of International
Terrorism, LAWFARE (Aug. 21, 2017, 1:59 pm), https://www.lawfareblog.com/criminal-law-should-treat-domestic-
terrorism-moral-equivalent-international-terrorism.
534 Samantha Michaels, Why So Many Violent White Supremacists Aren’t Charged with Domestic Terror, MOTHER
JONES (Apr. 26, 2019), https://www.motherjones.com/crime-justice/2019/04/why-so-many-violent-white-supremacists-
arent-charged-with-domestic-terrorism/.
535 Mary B. McCord, It’s Time for Congress to Make Domestic Terrorism a Federal Crime, LAWFARE (Dec. 5, 2018,
9:13 am), https://www.lawfareblog.com/its-time-congress-make-domestic-terrorism-federal-crime.
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Constitutional Issues
Criminal laws often raise constitutional issues, and the laws governing terrorism—both domestic
and international—are no exception. The nature of terrorism presents several constitutional
questions with respect to potential criminal and surveillance laws.536 For example, whether
Congress can outlaw acts of domestic terrorism depends, in part, on whether the Constitution
authorizes it to do so or reserves that power for the states.537 Likewise, commentators have
recognized a tension between the desire to regulate terrorist speech and the Constitution’s First
Amendment right to free speech.538 Further, domestic surveillance of terrorist activities implicates
the Fourth Amendment’s right to freedom from unreasonable searches and seizures.539 This
section summarizes three broad constitutional issues—federalism, First Amendment rights, and
Fourth Amendment rights—and discusses how these constitutional provisions may affect
domestic terrorism offenses and surveillance, including terrorism-related cyber activities.
Federalism
The Constitution “establishes a system of dual sovereignty between States and the Federal
Government,” under which “states retain substantial sovereign authority.”540 Principles of
federalism delineate the boundaries between federal and state power.541 Recognizing that one
such boundary concerns Congress’s ability to enact criminal laws, the Supreme Court has stated:
“The States possess primary authority for defining and enforcing the criminal law.”542 Congress is
not free to enact whatever criminal laws it wishes; it “may enact only those criminal laws that are
connected to one of its constitutionally enumerated powers.”543
As the Supreme Court explained in Torres v. Lynch:
As a result, most federal offenses include, in addition to substantive elements, a
jurisdictional one, like [an] interstate commerce requirement . . . . The substantive
elements “primarily define[] the behavior that the statute calls a ‘violation’ of federal
law,” . . . [while] [t]he jurisdictional element, by contrast, ties the substantive offense . . .

536 See United States v. U.S. Dist. Ct. (Keith), 407 U.S. 297, 313 (1972) (“National security cases . . . often reflect a
convergence of First and Fourth Amendment values not present in ‘ordinary’ crime. Though the investigative duty of
the executive may be stronger in such cases, so also is there greater jeopardy to constitutionally protected speech.”).
537 See, e.g., Torres v. Lynch, 136 S. Ct. 1619, 1624 (2016) (reiterating that “‘Congress cannot punish felonies
generally’” and instead “may enact only those criminal laws that are connected to one of its constitutionally
enumerated powers” (quoting Cohens v. Virginia, 19 U.S. (6 Wheat.) 264, 428 (1821)).
538 See, e.g., Michael Posner & Ryan Goodman, Terrorism and Other Dangerous Online Content: Exporting the First
Amendment?, JUST SECURITY (Mar. 26, 2021), https://www.justsecurity.org/75514/terrorism-and-other-dangerous-
online-content-exporting-the-first-amendment/ (discussing the United States’ reservation on First Amendment grounds
to Article 20 of the International Covenant on Civil and Political Rights (ICCPR), which otherwise requires signatories
to prohibit “‘any advocacy of national, racial, or religious hatred that constitutes incitement to discrimination, hostility,
or violence.’” (quoting ICCPR art. 20, Dec. 16, 1966, 999 U.N.T.S. 171)).
539 U.S. CONST. amend. IV.
540 Gregory v. Ashcroft, 501 U.S. 452, 457 (1991); U.S. CONST. amend. X (“The powers not delegated to the United
States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”).
541 Federalism, BLACK’S LAW DICTIONARY (11th ed. 2019). For a more detailed discussion of federalism principles, see
CRS Report R45323, Federalism-Based Limitations on Congressional Power: An Overview, coordinated by Andrew
Nolan and Kevin M. Lewis.
542 Engle v. Isaac, 456 U.S. 107, 128 (1982).
543 Torres v. Lynch, 136 S. Ct. 1619, 1624 (2016).
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to one of Congress’s constitutional powers[,] . . . thus spelling out the warrant for Congress
to legislate.[544]
In other words, “Congress cannot punish felonies generally”545 but instead must tie federal
criminal laws to a specific grant of congressional authority—a jurisdictional “hook.”546
In the international terrorism context, Congress has cited several of its constitutional powers to
serve as jurisdictional hooks, including the powers: (1) to punish crimes against the laws of
nations; (2) to carry out the treaty obligations of the United States; (3) over immigration and
naturalization; and (4) over interstate and foreign commerce.547 For example, 18 U.S.C. § 2332b,
which prohibits acts of terrorism transcending national boundaries, lists six jurisdictional bases:
(A) the mail or any facility of interstate or foreign commerce is used in furtherance of the
offense;
(B) the offense obstructs, delays, or affects interstate or foreign commerce, or would have
so obstructed, delayed, or affected interstate or foreign commerce if the offense had been
consummated;
(C) the victim, or intended victim, is the United States Government, a member of the
uniformed services, or any official, officer, employee, or agent of the legislative, executive,
or judicial branches, or of any department or agency, of the United States;
(D) the structure, conveyance, or other real or personal property is, in whole or in part,
owned, possessed, or leased to the United States, or any department or agency of the United
States;
(E) the offense is committed in the territorial sea (including the airspace above and the
seabed and subsoil below, and artificial islands and fixed structures erected thereon) of the
United States; or
(F) the offense is committed within the special maritime and territorial jurisdiction of the
United States.[548]
Should Congress decide to create a new domestic terrorism criminal law, it will need to consider
the constitutional basis—the jurisdictional hook—for such a law. Absent such a hook, a reviewing
court could find that Congress lacked congressional authority to prohibit the offense.
The First Amendment
The First Amendment to the Constitution provides: “Congress shall make no law respecting an
establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of
speech, or of the press; or the right of the people peaceably to assemble, and to petition the
Government for a redress of grievances.”549 In light of its ideological nature, terrorism implicates
the First Amendment in unique ways.550 This section provides a brief legal background on two of

544 Torres, 136 S. Ct. at 1624 (quoting Scheidler v. Nat’l Org. for Women, Inc., 547 U.S. 9, 18 (2006)).
545 Cohens v. Virginia, 19 U.S. (6 Wheat.) 264, 428 (1821).
546 Torres, 136 S. Ct. at 1625.
547 Antiterrorism and Effective Death Penalty Act of 1996, P.L. 104-132, § 301(a), 110 Stat. 1214, 1247.; see U.S.
CONST. art. I, § 8, cl. 3 (the power to regulate interstate and foreign commerce), cl. 4 (the power over immigration), cl.
10 (power to define and punish offenses against the law of nations), cl. 18 (the “necessary and proper” clause); id. art.
2, § 2, cl. 2 (the treaty power).
548 18 U.S.C. § 2332b(b)(1).
549 U.S. CONST. amend. I.
550 See, e.g., United States v. U.S. Dist. Ct. (Keith), 407 U.S. 297, 314 (1972) (“The danger to political dissent is acute
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these First Amendment rights—freedom of speech and freedom of association—before analyzing
how these rights may affect domestic terrorism laws in the context of material support, generally,
and Internet speech in particular.
Freedom of Speech
The First Amendment generally prevents the government551 from prohibiting speech because it
disapproves of the ideas that speech expresses.552 Courts presume that so-called content-based
regulations—that is, laws that “target speech based on its communicative content”553—are
unconstitutional.554 If a law is content-based, the government can overcome the presumption of
unconstitutionality by showing that the law: (1) furthers a compelling interest and (2) is narrowly
tailored to achieve that interest.555 This two-part test is called strict scrutiny.556
Although speech is generally protected under the First Amendment, the Supreme Court has long
considered political and ideological speech to be at the amendment’s core.557 Political speech
includes more than “the written or spoken word”;558 in some contexts, both money559 and
symbolic acts560 can constitute political speech. Content-based laws regulating political speech,
like laws regulating other protected speech, are subject to strict scrutiny.
There are several exceptions to the strict scrutiny test. In cases where laws are content-neutral—
that is, the laws are not content-based because they are “‘justified without reference to the content

where the Government attempts to act under so vague a concept as the power to protect ‘domestic security.’ Given the
difficulty of defining the domestic security interest, the danger of abuse in acting to protect that interest becomes
apparent.”).
551 In addition to the federal government, to which the First Amendment directly applies, state governments are subject
to the First Amendment through the Fourteenth Amendment. E.g. Reed v. Town of Gilbert, 576 U.S. 155, 163 (2015).
552 R.A.V. v. City of St. Paul, 505 U.S. 377, 382 (1992). For a more detailed discussion of the First Amendment’s right
to free speech, see CRS Report R45713, Terrorism, Violent Extremism, and the Internet: Free Speech Considerations,
by Victoria L. Killion, and CRS Report R45650, Free Speech and the Regulation of Social Media Content, by Valerie
C. Brannon.
553 Reed, 576 U.S. at 163. Content-based restrictions apply to speech “because of the topic discussed or the idea or
message expressed.” Id. Content-based restrictions fall into two categories: (1) laws that, on their face, draw
distinctions based on a speaker’s message, and (2) laws that, while “facially content-neutral . . . cannot be ‘justified
without reference to the content of the regulated speech,’ or that were adopted by the government ‘because of
disagreement with the message [the speech] conveys.’” Id. at 164 (quoting Ward v. Rock Against Racism, 491 U.S.
781, 791 (1989)).
554 Id.; R.A.V., 505 U.S. at 382 (“Content-based regulations are presumptively invalid.”).
555 Reed, 576 U.S. at 171.
556 Id.
557 W. Va. State Bd. of Educ. v. Barnette, 319 U.S. 624, 642 (1943) (“If there is any fixed star in our constitutional
constellation, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion,
or other matters of opinion . . . .”).
558 Texas v. Johnson, 491 U.S. 397, 404 (1989) (“The First Amendment literally forbids the abridgment only of
‘speech,’ but we have long recognized that its protection does not end at the spoken or written word.”).
559 Buckley v. Valeo, 424 U.S. 1, 19 (1976) (“A restriction on the amount of money a person or group can spend on
political communication during a campaign necessarily reduces the quantity of expression by restricting the number of
issues discussed, the depth of their exploration, and the size of the audience reached.”).
560 Johnson, 491 U.S. at 404 (recognizing that “conduct may be ‘sufficiently imbued with elements of communication
to fall within the scope of the First and Fourteenth Amendments’” when “‘[a]n intent to convey a particularized
message was present, and . . . the likelihood was great that the message would be understood by those who viewed it’”
(quoting Spence v. Washington, 418 U.S. 405, 409-11 (1974))).
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of the regulated speech,’” courts apply a lower standard of review.561 Under this test, called
intermediate scrutiny, the government must show that the challenged law is “narrowly tailored to
serve a significant governmental interest” and “leave[s] open ample alternative channels for
communication of the information.”562 Frequently, content-neutral laws meeting the intermediate
scrutiny test are said to “impose reasonable restrictions on the time, place, or manner of
speech.”563
The Supreme Court has also recognized limited categories of speech that the government can
regulate because of its content, such as obscenity and defamation.”564 In these cases, the
government can regulate these types of speech consistent with the First Amendment, provided it
does so in an otherwise content-neutral way.565 As the Supreme Court has recognized, “the
government may proscribe libel; but it may not make the further content discrimination of
proscribing only libel critical of the government.”566
The Court has recognized three categories of speech the government may regulate because of
content that are particularly relevant with respect to terrorism:
 Incitement, meaning speech “directed to inciting or producing imminent lawless
action and . . . likely to produce such action”;567
 True threats, which “encompass those statements where the speaker means to
communicate a serious expression of an intent to commit an act of unlawful
violence to a particular individual or group of individuals”;568 and
 Speech integral to criminal conduct, meaning speech “used as an integral part of
conduct in violation of a valid criminal statute,”569 such as conspiracy or
solicitation to commit a crime.570
Freedom of Association
Although not specifically listed in the First Amendment, the Supreme Court has long recognized
“a right to associate for the purpose of engaging in those activities protected by the First
Amendment—speech, assembly, petition for the redress of grievances, and the exercise of
religion.”571 This “implicit” right is premised on the idea that an individual’s enumerated First

561 Ward v. Rock Against Racism, 491 U.S. 781, 791 (1989) (quoting Clark v. Cmty. for Creative Non-Violence,
468 U.S. 288, 293 (1984)). A law regulating speech can be content neutral “even if it has an incidental effect on some
speakers but not others.” Id. (citing Reston v. Playtime Theatres, Inc., 475 U.S. 41, 47-48 (1986)).
562 Cmty. for Creative Non-Violence, 468 U.S. at 293.
563 Rock Against Racism, 491 U.S. at 791.
564 R.A.V. v. City of St. Paul, 505 U.S. 377, 382-83 (1992). For an overview of these categories, see CRS In Focus
IF11072, The First Amendment: Categories of Speech, by Victoria L. Killion.
565 R.A.V., 505 U.S. at 383-84.
566 Id. at 384.
567 Brandenburg v. Ohio, 395 U.S. 444, 447-48 (1969).
568 Virginia v. Black, 538 U.S. 343, 359 (2003). True threats do not include “political hyperbole.” Watts v. United
States, 394 U.S. 705, 708 (1969) (per curiam). The government may regulate threats of violence to “protect[]
individuals from the fear of violence, from the disruption that fear engenders, and from the possibility that the
threatened violence will occur.” R.A.V., 505 U.S. at 388.
569 Giboney v. Empire Storage & Ice Co., 336 U.S. 490, 498 (1949).
570 See United States v. Williams, 553 U.S. 285, 297-98 (2008).
571 Roberts v. U.S. Jaycees, 468 U.S. 609, 618 (1984); see id. (distinguishing this “freedom of expressive association”
from the “freedom of intimate association”).
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Amendment rights “could not be vigorously protected from interference by the State unless a
correlative freedom to engage in group effort toward those ends were not also guaranteed,” and it
includes “a corresponding right to associate with others in pursuit of a wide variety of political,
social, economic, education, religious, and cultural ends.”572 Government conduct may
impermissibly infringe on this right in a number of ways, including: (1) imposing penalties or
withholding benefits from individuals who are members of a disfavored group;573 (2) requiring
disclosure of the membership rolls of groups seeking anonymity;574 and (3) interfering with the
internal organization or affairs of a group.575 Courts typically apply free speech case law to
determine whether a law violates the right to free association.576
Material Support of Terrorism
In the context of terrorism, courts have considered the intersection of the freedoms of speech and
association with prohibitions on material support to terrorist organizations. In Holder v.
Humanitarian Law Project, the Supreme Court considered a First Amendment challenge to
18 U.S.C. § 2339B, which prohibits providing material support or resources to designated foreign
terrorist organizations.577 The plaintiffs in that case—two U.S. citizens and six domestic
organizations, including the Humanitarian Law Project—“claimed that they wished to provide
support for the humanitarian and political activities” of two designated foreign terrorist
organizations “in the form of monetary aid, other tangible aid, legal training, and political
advocacy.”578 The plaintiffs argued that, through Section 2339B, Congress violated their First
Amendment rights to free speech and association by banning “pure political speech.”579
The Court rejected this categorical argument, holding that because the plaintiffs were free to
engage in independent advocacy and expression regarding the organizations and could even join
those organizations without violating Section 2339B, Congress had not prohibited pure political
speech.580 Instead, the Court considered a “more refined” question of whether the government
may prohibit material support “in the form of speech.”581 The Court concluded:

572 Id. at 622 (citing, e.g., Citizens Against Rent Control/Coal. for Fair Housing v. Berkeley, 454 U.S. 290, 294 (1981)).
573 E.g. Healy v. James, 408 U.S. 169, 180-84 (1972).
574 E.g. Brown v. Socialist Workers ’74 Campaign Committee, 459 U.S. 87, 91-92 (1982).
575 E.g., Cousins v. Wigoda, 419 U.S. 477, 487-88 (1975); U.S. Jaycees, 468 U.S. at 623.
576 Compare U.S. Jaycees, 468 U.S. at 623 (“Infringements on [the right to associate for expressive purposes] may be
justified by regulations adopted to serve compelling state interests, unrelated to the suppression of ideas, that cannot be
achieved through means significantly less restrictive of associational freedoms.”), with Reed v. Town of Gilbert,
576 U.S. 155, 171 (2015) (a content-based restriction on speech is unconstitutional unless it “furthers a compelling
governmental interest and is narrowly tailored to that end”); see also Ashutosh Bhagwat, Associational Speech,
120 YALE L.J. 978, 982-95 (2011) (tracing the links in case law between freedom of speech and freedom of
association).
577 561 U.S. 1 (2010); see supra, § “Material Support to Foreign Terrorist Organizations Under 18 U.S.C. § 2339B.”
578 Humanitarian L. Project, 561 U.S. at 10.
579 Id. at 25.
580 Id. at 25-26. In support of this holding, the Court relied on the statute’s explicit inapplicability to “[i]ndividuals who
act entirely independently of the foreign terrorist organization to advance its goals or objectives,” 18 U.S.C.
§ 2339B(h), and guidance that it not be “construed or applied so as to abridge the exercise of rights guaranteed under
the First Amendment,” id. § 2339B(i), “find[ing] it significant that Congress has been conscious of its own
responsibility to consider how its actions may implicate constitutional concerns.” Humanitarian L. Project, 561 U.S. at
35-36.
581 Humanitarian L. Project, 561 U.S. at 28. The Court explained that, while material support “most often does not take
the form of speech at all[,] . . . when it does, the statute is carefully drawn to cover only a narrow category of speech to,
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At bottom, plaintiffs simply disagree with the considered judgment of Congress and the
Executive that providing material support to a designated foreign terrorist organization—
even seemingly benign support—bolsters the terrorist activities of that organization. That
judgment, however, is entitled to significant weight, and we have persuasive evidence
before us to sustain it. Given the sensitive interests in national security and foreign affairs
at stake, the political branches have adequately substantiated their determination that, to
serve the Government’s interest in preventing terrorism, it was necessary to prohibit
providing material support in the form of training, expert advice, personnel, and services
to foreign terrorist groups, even if the supporters meant to promote only the groups’
nonviolent ends.[582]
The Court cautioned, however, that its holding “is not to say that any future applications of the
material-support statute to speech or advocacy will survive First Amendment scrutiny. It is also
not to say that any other statute relating to speech and terrorism would satisfy the First
Amendment.”583
The Court’s decision in Humanitarian Law Project highlights some of the First Amendment
implications of anti-terrorism laws, particularly with respect to the way lawful advocacy,
ideology, and protest intersect with unlawful terrorist acts. If Congress decides to pass a law
prohibiting material support of domestic terrorism, it may face consideration of whether and how
such a law adequately safeguards the rights to free speech and association.584
Terrorist Speech and the Internet
Another First Amendment concern comes through the increased use of the internet and social
media to further terrorism.585 As domestic terrorist organizations expand their use of the internet
to recruit, train, and incite members to violence, Congress has considered legislation that would
create individual user or service provider liability for certain types of domestic terrorism
speech.586 Theoretically, however, a law addressing this topic could raise First Amendment issues.
For example, Congress likely could not prohibit all speech associated with terrorism. Such a
restriction would be content-based, and therefore subject to strict scrutiny587—a test that often is
“strict in theory, but fatal in fact.”588 In addition, a law broadly proscribing speech related to
terrorism likely would not fall within one of the narrow exceptions for incitement, true threats, or

under the direction of, or in coordination with foreign groups that the speaker knows to be terrorist organizations.” Id.
at 26.
582 Id. at 36.
583 Id. at 39.
584 See id. at 39 (“We also do not suggest that Congress could extend the same prohibition on material support at issue
here to domestic organizations.”); David Cole, The First Amendment’s Borders: The Place of Holder v. Humanitarian
Law Project in First Amendment Doctrine, 6 HARV. L. & POL’Y REV. 147 (2012).
585 See, e.g., Robert O’Harrow Jr. et al., The Rise of Domestic Extremism in America, WASH. POST (Apr. 12, 2021),
https://www.washingtonpost.com/investigations/interactive/2021/domestic-terrorism-data/ (“[E]xtremists have
exploited social media and the Internet in recent years to share theories, along with grievances, tactics, and potential
targets.”).
586 Several bills imposing new content moderation requirements on social media companies were introduced during the
116th Congress. See Online Terrorism Prevention Act, H.R. 9043, 116th Cong. (2020); Raising the Bar Act of 2019,
H.R. 5209, 116th Cong. (2019). This section focuses on laws regulating individual speech. For a discussion regarding
the regulation of social media providers, see CRS Report R45650, Free Speech and the Regulation of Social Media
Content, by Valerie C. Brannon.
587 See Reed v. Town of Gilbert, 576 U.S. 155, 163 (2015).
588 Fullilove v. Klutznick, 448 U.S. 448, 508 (1980) (Powell, J., concurring) (describing strict scrutiny as “virtually
impossible to satisfy”).
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speech integral to criminal conduct.589 Congress likely could, however, more narrowly tailor a
law to apply only to those categories of speech, particularly given the domestic security issues at
stake.
Fourth Amendment
The Fourth Amendment to the Constitution provides:
The right of the people to be secure in their persons, houses, papers, and effects, against
unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but
upon probable cause, supported by Oath or affirmation, and particularly describing the
place to be searched, and the persons or things to be seized.[590]
Under the Fourth Amendment, a search is a government intrusion on an individual’s reasonable
expectation of privacy591 or a physical intrusion into a constitutionally protected area.592
If a government action constitutes a search, then the Fourth Amendment generally requires the
government to demonstrate “probable cause” and obtain a warrant before executing the search.
“[T]he Supreme Court has interpreted the warrant clause of the Fourth Amendment to require
three elements.”593
First, warrants must be issued by neutral, disinterested magistrates. Second, those seeking
the warrant must demonstrate to the magistrate their probable cause to believe that “the
evidence sought will aid in a particular apprehension or conviction” for a particular offense.
Finally, “warrants must particularly describe the ‘things to be seized,’” as well as the place
to be searched.[594]
There are several exceptions to the warrant requirement. As potentially relevant to acts of
domestic terrorism, the Supreme Court has recognized an exception to the warrant requirement
“when ‘the exigencies of the situation make the needs of law enforcement so compelling that [a]
warrantless search is objectively reasonable under the Fourth Amendment.’”595 Likewise, the
Court has recognized an exception “when special needs, beyond the normal need for law
enforcement, make the warrant and probable-cause requirements impracticable.”596 Although the
Supreme Court has not directly addressed whether a warrant is required to collect foreign

589 See supra, § “Freedom of Speech.”
590 U.S. CONST. amend. IV. For a more detailed discussion of the Fourth Amendment in the context of terrorism
surveillance, see CRS Report R40138, Origins and Impact of the Foreign Intelligence Surveillance Act (FISA)
Provisions That Expired on March 15, 2020, by Edward C. Liu, and CRS Report R46541, Facial Recognition
Technology and Law Enforcement: Select Constitutional Considerations, by Kelsey Y. Santamaria.
591 The Supreme Court has recognized that “whether or not a Fourth Amendment ‘search’ has occurred is not [a] simple
[question.]” Kyllo v. United States, 533 U.S. 27, 31 (2001). “The touchstone of Fourth Amendment analysis is whether
a person has a ‘constitutionally protected reasonable expectation of privacy.’” California v. Ciraolo, 476 U.S. 207, 211
(1986) (quoting Katz v. United States, 389 U.S. 347, 360 (1967) (Harlan, J., concurring)). This test is a two-part
inquiry: (1) “has the individual manifested a subjective expectation of privacy in the object of the challenged search,”
and (2) “is society willing to recognize that expectation as reasonable?” Id. (citing Smith v. Maryland, 442 U.S. 735,
740 (1979)). If both inquiries are satisfied, then a government intrusion on that reasonable expectation of privacy
constitutes a Fourth Amendment search. Id.
592 See United States v. Jones, 565 U.S. 400, 506-07 (2012) (recognizing that “Katz did not repudiate” the
understanding that such government conduct constitutes a search).
593 In re Sealed Case, 310 F.3d 717, 738 (FISA Ct. Rev. 2002).
594 Dalia v. United States, 441 U.S. 238, 255 (1979) (citations omitted).
595 Kentucky v. King, 563 U.S. 452, 460 (2011) (quoting Mincey v. Arizona, 437 U.S. 385, 394 (1978)).
596 Griffin v. Wisconsin, 483 U.S. 868, 873 (1987) (internal quotation marks omitted).
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intelligence,597 at least one court, applying the “special needs” doctrine, has held that a warrant is
not required to do so.598
Application to Domestic Terrorism Surveillance
Congress may consider whether and how any new domestic terrorism legislation implicates
Fourth Amendment concerns. In contrast to foreign intelligence collection, the government
generally must obtain a warrant to conduct domestic surveillance.599 In this vein, the Supreme
Court has held that the following types of conduct, among others, constitute a Fourth Amendment
search: (1) recording the contents of telephone calls made from public telephone booths;600 (2)
conducting electronic surveillance of domestic organizations on national security grounds;601 and
(3) placing a GPS tracker on a private vehicle.602
General Fourth Amendment principles also apply in the context of cyber activities, such as
internet speech: where U.S. persons have a reasonable expectation of privacy in online activities,
the Fourth Amendment will likely require the government to show probable cause and obtain a
warrant before conducting a search.603 The Supreme Court has held that warrants are required to
search the contents of an individual’s cell phone604 and to request a user’s cell phone location data
from a service provider.605 Likewise, the Sixth Circuit has held that users enjoy “a reasonable
expectation of privacy in the contents of emails ‘that are stored with, or sent through, a
commercial [internet service provider].’”606
Domestic terrorist organizations increasingly use the internet and other cyber tools—such as
social media posts, email, and text messages—to recruit, train, and coordinate members.607 When
conducting surveillance of these activities, there may be some exceptions to general Fourth
Amendment rules in cases involving exigent circumstances or special needs.608 There is, however,

597 See, e.g., United States v. U.S. Dist. Ct. (Keith), 407 U.S. 297, 321-22 (1972) (“We have not addressed[, a]nd
express no opinion as to, the issues which may be involved with respect to activities of foreign powers or their agents.”)
598 In re Directives Pursuant to Section 105B of Foreign Intelligence Surveillance Act, 551 F.3d 1004, 1012 (FISA Ct.
Rev. 2008) (“[W]e hold that a foreign intelligence exception to the Fourth Amendment’s warrant requirement exists
when surveillance is conducted to obtain foreign intelligence for national security purposes and is directed against
foreign powers or agents of foreign powers reasonably believed to be located outside the United States.”). The FISA
Court of Review cautioned, however, that its holding “does not give the government carte blanche: even though the
foreign intelligence exception applies in a given case, governmental action intruding on individual privacy interests
must comport with the Fourth Amendment’s reasonableness requirement.” Id.
599 See, e.g., Carpenter v. United States, 138 S. Ct. 2206, 2214 (2018) (recognizing that “a central aim of the Framers
[when adopting the Fourth Amendment] was ‘to place obstacles in the way of a too permeating police surveillance’”
(quoting United States v. Di Re, 332 U.S. 581, 595 (1948))); Keith, 407 U.S. at 321 (holding that the government’s
national security “concerns do not justify departure in this case from the customary Fourth Amendment requirement of
judicial approval prior to initiation of a search or surveillance”). As the Court recognized in Keith, “[a]lthough some
added burden will be imposed upon the Attorney General” by requiring a warrant for domestic surveillance, “this
inconvenience is justified in a free society to protect constitutional values.” 407 U.S. at 321.
600 Katz v. United States, 389 U.S. 347, 358-59 (1967).
601 Keith, 407 U.S. at 323-24.
602 United States v. Jones, 565 U.S. 400, 404 (2012).
603 See California v. Ciraolo, 476 U.S. 207, 211 (1986).
604 Riley v. California, 573 U.S. 373, 401 (2014).
605 Carpenter v. United States, 138 S. Ct. 2206, 2223 (2018).
606 United States v. Warshak, 631 F.3d 266, 288 (6th Cir. 2010).
607 See O’Harrow, supra note 585.
608 See Kentucky v. King, 563 U.S. 452, 460 (2011) (recognizing an exception to the warrant requirement in exigent
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“no precedent for the proposition that whether a search has occurred depends on the nature of the
crime being investigated.”609 Thus, Congress likely could not create a blanket exception to the
Fourth Amendment for cases involving domestic terrorism.
Legislative Proposals
This section summarizes domestic terrorism-related legislation introduced in the 116th and 117th
Congresses.610 These bills generally would adopt the definition of domestic terrorism in 18 U.S.C.
§ 2331, either in whole or with modifications, and would create new law enforcement resources
or priorities. In addition, several of the bills would recognize a new criminal offense of domestic
terrorism. Table 1 compares the bills’ treatment of four subjects: (1) the definition of domestic
terrorism each bill would adopt; (2) whether the bill would create a new domestic terrorism
criminal offense; (3) whether the bill would create new reporting requirements; and (4) whether
the bill would create a new federal agency or office to address domestic terrorism.
117th Congress
Domestic Terrorism Prevention Act of 2021
The Domestic Terrorism Prevention Act of 2021 (DTPA 2021), introduced as companion bills in
the House of Representatives611 and the Senate,612 would create new offices in the Department of
Homeland Security (DHS), Department of Justice (DOJ) National Security Division, and FBI to
“monitor, analyze, investigate, and prosecute”613 domestic terrorism. The bills would adopt
18 U.S.C. § 2331(5)’s definition domestic terrorism, excluding:
acts perpetrated by individuals associated with or inspired by—
(A) a foreign person or organization designated as a foreign terrorist organization
under section 219 of the Immigration and Nationality Act (8 U.S.C. [§] 1189);
(B) an individual or organization designated under Executive Order 13224 (50 U.S.C.
[§] 1701 note); or
(C) a state sponsor of terrorism as determined by the Secretary of State under section
6(j) of the Export Administration Act of 1979 (50 U.S.C. [§] 4605), section 40 of the Arms
Control Export Act (22 U.S.C. [§] 2780), or section 620A of the Foreign Assistance Act of
1961 (22 U.S.C. [§] 2371).[614]

circumstances); Griffin v. Wisconsin, 483 U.S. 868, 873 (1987).
609 United States v. Jones, 565 U.S. 400, 412 (2012).
610 CRS searched Congress.gov for bills—but not resolutions or amendments—whose titles, summaries, or text include
the phrases “domestic terror” or “domestic terrorism.” This report summarizes those bills that would: (1) establish new
federal programs dedicated or relating to domestic terrorism; (2) modify the definition of domestic terrorism in
18 U.S.C. § 2331; or (3) create new federal crimes related to domestic terrorism. It excludes bills with either a narrower
focus, like hate crimes or reference to specific events (such as the events of January 6, 2021, at the U.S. Capitol) or a
broader focus, like programs to combat terrorism generally.
611 DTPA 2021, H.R. 350, 117th Cong. (2021).
612 DTPA 2021, S. 964, 117th Cong. (2021).
613 Id. § 3(a).
614 Id. § 2(2).
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The bill would also create new reporting, training, and inter-agency coordination requirements.615
Domestic Terrorism and Hate Crimes Prevention Act of 2021
The Domestic Terrorism and Hate Crimes Prevention Act of 2021616 is substantially similar to
DTPA 2021, with one exception. In addition to domestic terrorism-related provisions that mirror
DTPA 2021, the bill would also require the Attorney General to undertake “expedited review” of
hate crimes related to the spread of Coronavirus Disease 2019 (COVID-19).617
Commission on Domestic Terrorism Act of 2021
The Commission on Domestic Terrorism Act of 2021618 would establish a new National
Commission on Domestic Terrorism tasked with investigating the federal government’s response
to domestic terror.619 Specifically, the Commission would: (1) examine the government’s prior
failures to respond to or prevent acts of domestic terrorism;620 (2) “identify, review, and evaluate”
lessons learned from domestic terrorism incidents;621 and (3) submit initial and final reports
containing its findings and recommendations.622 The bill would adopt § 2331’s definition of
domestic terrorism.623
116th Congress
Domestic Terrorism Prevention Act of 2020
The Domestic Terrorism Prevention Act of 2020, introduced as companion bills in the House of
Representatives624 and the Senate,625 was substantially similar to DTPA 2021.
Terrorism Reporting and Classifying Act of 2019
The Terrorism Reporting and Classifying Act of 2019626 would have created an interagency
working group to establish a standard definition of domestic terrorism and create and maintain a
database of acts of domestic terrorism.627 The bill would have required the working group to

615 Id. §§ 3(b)-(c), 4, 5.
616 Domestic Terrorism and Hate Crimes Prevention Act of 2021, S. 963, 117th Cong. (2021).
617 Id. § 7.
618 Commission on Domestic Terrorism Act of 2021, H.R. 1178, 117th Cong. (2021).
619 Id. § 2.
620 Id. § 5(1).
621 Id. § 5(2).
622 Id. § 11(a)-(b).
623 Id. § 12.
624 Domestic Terrorism Prevention Act of 2020, H.R. 5602, 116th Cong. (2020).
625 Domestic Terrorism Prevention Act of 2020, S. 3190, 116th Cong. (2020).
626 Terrorism Reporting and Clarifying Act of 2019, S. 3118, 116th Cong. (2019).
627 Id. § 3(d).
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submit an annual report to Congress.628 The bill would have adopted § 2331’s definition of
domestic terrorism but would have authorized agencies to refine this definition.629
Confronting the Threat of Domestic Terrorism Act
The Confronting the Threat of Domestic Terrorism Act630 would have created a new domestic
terrorism criminal offense, subject to the same penalties as terrorism transcending national
boundaries under 18 U.S.C. § 2332b(c).631 Specifically, the new criminal provision would have
applied to any individual who,
with the intent to intimidate or coerce a civilian population, influence the policy of
government by intimidation or coercion, or affect the conduct of a government by mass
destruction, assassination, or kidnapping—
(A) knowingly kills, kidnaps, maims, commits an assault resulting in serious bodily
injury, or assaults with a dangerous weapon any person within the United States; or
(B) creates a substantial risk of serious bodily injury to any other person by knowingly
destroying or damaging any structure, conveyance, or other real or personal property within
the United States or by attempting or conspiring to destroy or damage any structure,
conveyance, or other real or personal property within the United States[.632]
It would also have applied to individuals who threatened, attempted, or conspired to commit such
acts.633 For the provision to apply, the individual must have committed the offense under one of
eight circumstances giving rise to federal jurisdiction, such as travel across state lines or use of
the mail.634 In addition to its penal provisions, the bill would have required a report assessing
those provisions’ impact on civil rights.635 The bill would not have expressly adopted a definition
of domestic terrorism, but its language tracks with the current definition in § 2331(5).636
Domestic Terrorism Information Act of 2019
The Domestic Terrorism Information Act of 2019637 would have required the Attorney General,
within 180 days of enactment, to submit a report to Congress providing information on domestic
terrorism. Specifically, the bill would have required the report to include: (1) the number of

628 Id. § 5.
629 Id. §§ 2(6), 3(d)(1).
630 Confronting the Threat of Domestic Terrorism Act, H.R. 4192, 116th Cong. (2019).
631 Id. sec. 2(a) (internal quotations removed).
632 Id.
633 Id.
634 Id. The eight enumerated circumstances are offenses: (1) using the mail or a facility of interstate or foreign
commerce in furtherance of the offense; (2) obstructing, delaying, or affecting interstate or foreign commerce; (3)
traveling across state lines or national borders or using a facility of interstate or foreign commerce; (4) where the victim
is the U.S. government, a member of the uniformed services, or an officer or employee of the U.S. government; (5)
where the property affected is, in whole or in part, owned or leased by the United States; (6) employing a firearm,
dangerous weapon, or weapon of mass destruction that has traveled in interstate or foreign commerce; (7) committed in
the U.S. territorial sea; or (8) committed within the special maritime and territorial jurisdiction of the United States. Id.
A facility of interstate or foreign commerce “includes means of transportation and communication.” Id.; 18 U.S.C.
§ 1958(b)(2).
635 H.R. 4192, § 2(e).
636 Compare id. § 2(a) with 18 U.S.C. § 2331(5).
637 Domestic Terrorism Information Act of 2019, H.R. 4190, 116th Cong. (2019).
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arrests by federal law enforcement “pursuant to an investigation of an act of domestic terrorism,”
including the results of those investigations and any charges filed;638 (2) the number of
individuals killed by domestic terrorism;639 and (3) the DOJ’s methods and strategies for
preventing domestic terrorism.640 The bill would have adopted § 2331’s domestic terrorism
definition.641
Domestic Terrorism Penalties Act of 2019
The Domestic Terrorism Penalties Act of 2019642 would have recognized six criminal offenses as
acts of domestic terrorism and defined penalties for them: (1) killing; (2) kidnapping; (3) assault
with a deadly weapon; (4) assault resulting in serious bodily injury; (5) destruction of or damage
to structures, conveyances, or other real or personal property; and (6) an attempt or conspiracy to
commit one of the other offenses.643 The new provisions would have applied only to individuals
who committed one or more of these acts “with the intent to intimidate or coerce a civilian
population or influence, affect, or retaliate against the policy or conduct of a government.”644 In
addition, the new provisions would not have applied unless an individual acted in one of three
circumstances giving rise to federal jurisdiction: (1) against any person or property within the
United States in a manner employing or affecting interstate or foreign commerce; (2) against any
property owned, leased, or used by the United States; or (3) against any property in the United
States owned, leased, or used by a foreign government.645
Domestic and International Terrorism DATA Act
The Domestic and International Terrorism DATA Act would have required the Secretary of
Homeland Security, the Attorney General, and the FBI Director to submit a joint report on
domestic and international terrorism to Congress each of the six fiscal years after the bill’s
enactment.646 The bill would also have required the Comptroller General to conduct an annual
audit of the joint report.647 In addition, the bill would have required the Homeland Security
Secretary to submit a report to Congress discussing, among other things, connections between
international and domestic terrorism and the use of online platforms for such terrorism.648 The bill
would have adopted § 2331’s domestic terrorism definition.649

638 Id. § 2(a)(1).
639 Id. § 2(a)(2).
640 Id. § 2(a)(3).
641 Id. § 2(b).
642 Domestic Terrorism Penalties Act of 2019, H.R. 4187, 116th Cong. (2019).
643 Id. § 2(a).
644 Id.
645 Id.
646 Domestic and International Terrorism DATA Act, H.R. 3106, 116th Cong. § 101 (2019).
647 Id. § 102.
648 Id. § 201.
649 Id. § 2(3).
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Domestic Terrorism Prevention Act of 2019
The Domestic Terrorism Prevention Act of 2019, introduced in both the House of
Representatives650 and the Senate,651 was substantially similar to DTPA 2021.

Table 1. Comparison of Domestic Terrorism Legislation
New Federal
Definition of
New Penal New Reporting
Agency or
Bill
Domestic Terrorism
Provision
Requirements
Office
117th Congress

Domestic Terrorism
18 U.S.C. § 2331(5),
—
Biannual (§ 3(b))
Offices in DHS,
Prevention Act of 2021,
with exclusions (§ 2(2))
DOJ, and FBI
H.R. 350 and S. 964
(§ 3(a))
Domestic Terrorism and
18 U.S.C. § 2331(5),
—
Biannual (§ 3(b))
Offices in DHS,
Hate Crimes Prevention Act
with exclusions (§ 2(2))
DOJ, and FBI
of 2021, S. 963
(§ 3(a))
Commission on Domestic
18 U.S.C. § 2331(5)
—
Periodic
Commission (§ 2)
Terrorism Act of 2021, H.R.
(§ 12)
(§ 11(a)-(b))
1178
116th Congress

Domestic Terrorism
18 U.S.C. § 2331(5),
—
Biannual (§ 4(b))
Offices in DHS,
Prevention Act of 2020,
with exclusions (§ 3(2))
DOJ, and FBI
H.R. 5602 and S. 3190
(§ 4(a))
Terrorism Reporting and
18 U.S.C. § 2331(5)
—
Annual (§ 5)
Interagency
Classifying Act of 2019, S.
(§ 2(6))
working group (§
3118
3)
Confronting the Threat of
—
§ 2(a)
One-time (§ 2(e))
—
Domestic Terrorism Act,
H.R. 4192
Domestic Terrorism
18 U.S.C. § 2331(5)
—
One-time (§ 2(a))
—
Information Act of 2019,
(§ 2(b))
H.R. 4190
Domestic Terrorism
—
§ 2(a)
—
—
Penalties Act of 2019, H.R.
4187
Domestic and International
18 U.S.C. § 2331(5)
—
Six annual
—
Terrorism DATA Act, H.R.
(§ 2(3))
reports (§ 101);
3106
annual (§ 201)
Domestic Terrorism
18 U.S.C. § 2331(5),

Biannual (§ 4(b))
Offices in DHS,
Prevention Act of 2019,
with exceptions (§ 3(2))
DOJ, and FBI
H.R. 1931 and S. 894
(§ 4(a))
Source: CRS, based on information from H.R. 350, S. 964, S. 963, and H.R. 1178 (117th Congress) and H.R.
5602, S. 3190, S. 3118, H.R. 4192, H.R. 4190, H.R. 4187, H.R. 3106, H.R. 1931, and S. 894.

650 Domestic Terrorism Prevention Act of 2019, H.R. 1931, 116th Cong. (2019).
651 Domestic Terrorism Prevention Act of 2019, S. 894, 116th Cong. (2019).
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Author Information

Peter G. Berris
Jonathan M. Gaffney
Legislative Attorney
Legislative Attorney

Michael A. Foster

Legislative Attorney

Disclaimer
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under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
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