Order Code RS22443
Updated July 26, 2006
CRS Report for Congress
Received through the CRS Web
Border Security and Military Support:
Legal Authorizations and Restrictions

Stephen R. Viña
Legislative Attorney
American Law Division
Summary
The military generally provides support to law enforcement and immigration
authorities along the southern border. Reported escalations in criminal activity and
illegal immigration, however, have prompted some lawmakers to reevaluate the extent
and type of military support that occurs in the border region. On May 15, 2006,
President Bush announced that up to 6,000 National Guard troops would be sent to the
border to support the Border Patrol. Addressing domestic laws and activities with the
military, however, might run afoul of the Posse Comitatus Act, which prohibits use of
the armed forces to perform the tasks of civilian law enforcement unless explicitly
authorized. There are alternative legal authorities for deploying the National Guard, and
the precise scope of permitted activities and funds may vary with the authority exercised.
This report will be updated as warranted.
Background
The Secretary of the Department of Homeland Security (DHS) is charged with
preventing the entry of terrorists, securing the borders, and carrying out immigration
enforcement functions. The Department of Defense’s (DOD) role in the execution of this
responsibility is to provide support to DHS and other federal, state and local (and in some
cases foreign) law enforcement agencies, when requested. Since the 1980s, the DOD
(and National Guard), as authorized by Congress, has conducted a wide variety of
counterdrug support missions along the borders of the United States. After the attacks of
September 11, 2001, military support was expanded to include counterterrorism activities.
Although the DOD does not have the “assigned responsibility to stop terrorists from
coming across our borders,”1 its support role in counterdrug and counterterrorism efforts
appears to have increased the Department’s profile in border security.
1 Dep’t. of Defense, Strategy for Homeland Defense and Civil Support, at 5 (June 2005) available
at [http://www.fas.org/irp/agency/dod/homeland.pdf].
Congressional Research Service ˜ The Library of Congress

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Some states, particularly those along the southern border that are experiencing
reported escalations in crime and illegal immigration, are welcoming the increased
military role and have taken steps to procure additional military resources. Governor
Janet Napolitano of Arizona, for example, sent the DOD a request for federal funding to
support the state’s deployment of National Guard troops to the border after reportedly
exhausting available state resources for combating illegal immigration and drug
trafficking.2 Others view the increased presence of military support along the borders as
undiplomatic, potentially dangerous,3 and a further strain on already overextended military
resources.4 Nonetheless, the concerns over aliens and smugglers exploiting the porous
southern border continue to grow, and some now argue that the military should play a
much larger and more direct role in border security.
On May 15, 2006, President Bush announced that up to 6,000 National Guard troops
would be sent to the southern border to support the Border Patrol. According to the
President, the Guard will assist the Border Patrol by operating surveillance systems,
analyzing intelligence, installing fences and vehicle barriers, building roads, and
providing training.5 Guard units will not be involved in direct law-enforcement activities
and will be under the control of the Governors. The Administration has indicated that the
vast majority of the force at the border would be drawn from Guardsmen performing their
regularly scheduled, two- or three-week annual training, pursuant to Title 32 of the U.S.
Code (see later discussion).6 Initial deployments of Guardsmen to the border began in
June 2006 under the mission name, “Operation Jump Start.” In Congress, the
Comprehensive Immigration Reform Act of 2006 (S. 2611), as passed by the Senate,
would allow the Governor of a state, with the approval of the Secretary of Defense, to
order units of the National Guard of such state to perform specified activities (e.g.,
reconnaissance, construction) during annual training duty along the southern land border
for border security purposes. Section 1026 of the House-passed Defense Authorization
Act for FY2007 (H.R. 5122) would allow the Secretary of Defense, upon a request of the
Secretary of DHS, to assign members of the armed forces to assist DHS in preventing the
entry of terrorists, drug traffickers, and illegal aliens.7
Military Assistance Along the Border
The military does not appear to have a direct legislative mandate to protect or patrol
the border or to engage in immigration enforcement. Indeed, direct military involvement
2 See [http://azgovernor.gov/dms/upload/NR_030706%20Rumsfeld_Chertoff%20Letter.pdf].
3 In 1997, a Marine who was part of a four-man border observation team near Redford, Texas,
shot and fatally wounded an 18-year old man after reportedly taking fire. See Oversight
Investigation of the Death of Esequiel Hernandez, Jr.,
A Report of Chairman Lamar Smith to the
Subcommittee on Immigration and Claims of the Committee on the Judiciary, 105th Cong. 2d
Sess. (Nov. 1998).
4 Peter Baker, Bush Set to Send Guard to Border, THE WASHINGTON POST, May 15, 2006.
5 Stephen Dinan, Bush Calls for Guard on Border, THE WASHINGTON TIMES, May 16, 2006.
6 The White House, Press Briefing on the President’s Immigration Reform Plan, May 16, 2006,
available at [http://www.whitehouse.gov/news/releases/2006/05/20060516-2.html].
7 H.R. 1986, H.R. 3938, H.R. 3333, and H.R. 4437 would propose similar measures.

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in law enforcement activities without proper statutory authorization might run afoul of the
Posse Comitatus Act.8 The military does have, however, general legislative authority that
allows it to provide support to federal, state, and local law enforcement agencies (LEA)
in counterdrug and counterterrorism efforts, which might indirectly provide border
security and immigration control assistance. Military personnel for these operations are
drawn from the active and reserve forces of the military and from the National Guard.
Restrictions. The primary restriction on military participation in civilian law
enforcement activities is the Posse Comitatus Act (PCA).9 The PCA prohibits the use of
the Army and Air Force to execute the domestic laws of the United States except where
expressly authorized by the Constitution or Congress. The PCA has been further applied
to the Navy and Marine Corps by legislative and administrative supplements. For
example, 10 U.S.C. §375, directs the Secretary of Defense to promulgate regulations
forbidding the direct participation “by a member of the Army, Navy, Air Force, or
Marines in a search, seizure, arrest, or other similar activity” during support activities to
civilian law enforcement agencies. DOD issued Directive 5525.5, which outlines its
policies and procedures for supporting federal, state, and local LEAs. According to the
Directive, the following forms of direct assistance are prohibited: (1) interdiction of a
vehicle, vessel, aircraft, or other similar activity; (2) a search or seizure; (3) an arrest,
apprehension, stop and frisk, or similar activity; and (4) use of military personnel in the
pursuit of individuals, or as undercover agents, informants, investigators, or interrogators.
It is generally accepted that the PCA does not apply to the actions of the National Guard
when not in federal service.10 As a matter of policy, however, National Guard regulations
stipulate that its personnel are not, except for exigent circumstances or as otherwise
authorized, to directly participate in the arrest or search of suspects or the general public,
or become involved in the chain of custody for any evidence.11
Authorizations. The PCA does not apply “in cases and under circumstances
expressly authorized by the Constitution.” Under the Constitution, Congress is
empowered to call forth the militia to execute the laws of the Union.12 The Constitution,
however, contains no provision expressly authorizing the President to use the military to
execute the law. The question of whether the constitutional exception includes instances
where the President is acting under implied or inherent constitutional powers is one the
courts have yet to answer. DOD regulations, nonetheless, do assert two constitutionally
based exceptions — sudden emergencies and protection of federal property.13 The PCA
also does not apply where Congress has expressly authorized use of the military to
execute the law. Congress has done so in three ways: by giving a branch of the armed
8 For a more complete discussion of the Posse Comitatus Act, see CRS Report 95-964, The Posse
Comitatus Act & Related Matters: The Use of Military to Execute Civilian Law,
by Charles
Doyle.
9 18 U.S.C. §1385.
10 See CRS Report 95-964, at 42 (citing numerous cases); see also DOD Directive 5525.5.
11 NGR 500-2/ANGI 10-801, National Guard Counterdrug Support, March 31, 2000.
12 U.S. Const. Art. I, §8, cl. 15. In addition, the PCA does not apply to actions furthering a
military purpose. See CRS Report 95-964, at 31 (describing the exception).
13 32 C.F.R. §215.4.

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forces civilian law enforcement authority (e.g., the Coast Guard), by addressing certain
circumstances with more narrowly crafted legislation,14 and by establishing general rules
for certain types of assistance.

The military indirectly supports border security and immigration control efforts
under general legislation that authorizes the armed forces to support federal, state, and
local LEAs. Since the early 1980s, Congress has periodically authorized an expanded role
for the military in providing support to LEAs. Basic authority for most DOD assistance
was originally passed in 1981 and is contained in Chapter 18 of Title 10 of the U.S. Code
— Military Support for Civilian Law Enforcement Agencies. Under Chapter 18 of Title
10, Congress authorizes DOD to share information (§371); loan equipment and facilities
(§372); provide expert advice and training (§373); and maintain and operate equipment
(§374). For federal LEAs, DOD personnel may be made available, under §374, to
maintain and operate equipment in conjunction with counterterrorism operations
(including the rendition of a suspected terrorist from a foreign country) or the enforcement
of counterdrug laws, immigration laws, and customs requirements. For any civilian LEA,
§374 allows DOD personnel to maintain and operate equipment for a variety of purposes,
including aerial reconnaissance and the detection, monitoring, and communication of air
and sea traffic, and of surface traffic outside the United States or within 25 miles of U.S.
borders, if first detected outside the border. Congress placed several stipulations on
Chapter 18 assistance, e.g., LEAs must reimburse DOD for the support it provides unless
the support “is provided in the normal course of military training or operations” or if it
“results in a benefit...substantially equivalent to that which would otherwise be obtained
from military operations or training.”15 Pursuant to §376, DOD can only provide such
assistance if it does not adversely affect “the military preparedness of the United States.”
Congress incorporated posse comitatus restrictions into Chapter 18 activities in §375.
In 1989, Congress began to expand the military’s support role. For example,
Congress directed DOD, to the maximum extent practicable, to conduct military training
exercises in drug-interdiction areas, and made the DOD the lead federal agency for the
detection and monitoring of aerial and maritime transit of illegal drugs into the United
States.16 Congress later provided additional authorities for military support to LEAs
specifically for counterdrug purposes in the National Defense Authorization Act for
FY1991.17 Section 1004 authorized DOD to extend support in several areas to any
federal, state, and local (and sometimes foreign) LEA requesting counterdrug assistance.
This section has been extended regularly and is now in force through the end of FY2006.18
As amended, §1004 authorizes the military to: maintain, upgrade, and repair military
equipment; transport federal, state, local, and foreign law enforcement personnel and
equipment within or outside the U.S.; establish bases for operations or training; train law
14 See, e.g., 10 U.S.C. §§ 331-333 (to suppress insurrections).
15 10 U.S.C. §377.
16 National Defense Authorization Act for FY1990 and 1991, P.L. 101-189, Div. A, Tit. XII,
§1202(a)(1), codified at 10 U.S.C. §124. A similar provision was first passed as part of the
National Defense Authorization for FY1989 (P.L. 100-456), but was repealed by P.L. 101-189.
17 P.L. 101-510, Div. A, Tit. X, §1004, codified at 10 U.S.C. §374 note.
18 P.L. 107-107, Div. A, Tit. X, §1021 (extending §1004 through FY2006).

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enforcement personnel in counterdrug activities; detect, monitor, and communicate
movements of air, sea, and surface traffic outside the U.S., and within 25 miles of the
border if the detection occurred outside the U.S.; construct roads, fences, and lighting
along U.S. border; provide linguists and intelligence analysis services; conduct aerial and
ground reconnaissance; and establish command, control, communication, and computer
networks for improved integration of law enforcement, active military, and National
Guard activities. Section 1004 incorporates the posse comitatus restrictions of Chapter
18.19 Unlike Chapter 18, however, this law does allow support which could affect
military readiness in the short-term, provided the Secretary of Defense believes the
support outweighs such short-term adverse effect.
The National Guard
The National Guard is a military force that is shared by the states and the federal
government and often assists in counterdrug and counterrrorism efforts. After September
11, for example, President Bush deployed roughly 1,600 National Guard troops for six-
months under Title 10 authority to support federal border officials and provide a
heightened security presence.20 Under “Title 10 duty status,” National Guard personnel
operate under the control of the President, receive federal pay and benefits, and are subject
to the PCA.21 Typically, however, the National Guard operates under the control of state
and territorial Governors. In “state active duty” National Guard personnel operate under
the control of their Governor, are paid according to state law, can perform activities
authorized by state law, and are not subject to the restrictions of the PCA.
Because border security is primarily a federal concern, states, such as Arizona, have
looked to the federal government for funding to support some of their National Guard
activities. Under Title 32 of the U.S. Code, National Guard personnel generally serve a
federal purpose and receive federal pay and benefits, but command and control remains
with the Governor. This type of service is commonly referred to as “Title 32 duty status,”
and examples are discussed below. According to the Administration, the deployment of
the 6,000 Guardsmen derives its authority from 32 U.S.C. §502(a), which allows the
Secretary of the Army and Air Force to prescribe regulations for National Guard drill and
training and §502(f), described below.22
State Drug Plan. Federal funding may be provided to a state for the
implementation of a drug interdiction program in accordance with 32 U.S.C. §112. Under
this section, the Secretary of Defense may grant funding to the Governor of a state who
submits a “drug interdiction and counterdrug activities plan” that satisfies certain statutory
requirements. The Secretary of Defense is charged with examining the sufficiency of the
19 Id. at §1021(g).
20 Maj. Gen. Timothy J. Lowenberg, The Role of the National Guard in National Defense and
Homeland Security, (Sept. 2005) available at [http://www.findarticles.com/p/articles/mi_qa3731/
is_200509/ai_n15638615/print] [hereinafter Lowenberg, The Role of the National Guard].
21 10 U.S.C. §§12301-12304. However, it appears that the National Guard could be deployed by
the President under 10 U.S.C. §§331-333 and §12406 to “execute the laws of the United States.”
22 Memorandum of Agreement between the States of Arizona, California, New Mexico, and
Texas and the Department of Defense, Operation Jump Start (June 2, 2006).

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drug interdiction plan and determining whether the distribution of funds would be proper.
While the emphasis is certainly on counterdrug efforts, a state plan might include some
related border security and immigration-related functions that overlap with drug
interdiction activities. Arizona’s drug interdiction plan, for example, recognizes related
border issues created by human smuggling and terrain vulnerabilities with respect to the
illegal entry of aliens into the United States.23 By approving the State of Arizona’s drug
interdiction plan, the Secretary of Defense has enabled the Arizona National Guard to
engage in some border security measures.
Other Duty. Section 502(f) of Title 32 has been used to expand the operational
scope of the National Guard beyond its specified duties. This provision provides that “a
member of the National Guard may ... without his consent, but with the pay and
allowances provided by law ... be ordered to perform training or other duty” in addition
to those he is already prescribed to perform (emphasis added). This is the provision of
law that was used to provide federal pay and benefits to the National Guard personnel
who provided security at many of the nation’s airports after September 11 and who
participated in Katrina and Rita-related disaster relief operations. States, such as Arizona,
have argued that the “other duty” language should be liberally applied (like it was for
Hurricane Katrina and Rita) to include activities associated with border security efforts.24
Some question, however, whether domestic operations, in general, are a proper use of this
Title 32 authority.25
Homeland Defense Activity. In 2004, Congress passed another law that could
arguably provide federal funding for National Guard personnel conducting border security
operations under Title 32.26 Chapter 9 of Title 32 of the U.S. Code authorizes the
Secretary of Defense to provide federal funding at his discretion to a state, under the
authority of the Governor of that state, for the use of their National Guard forces if there
is a “necessary and appropriate” “homeland defense activity.”27 A “homeland defense
activity” is statutorily defined as “an activity undertaken for the military protection of the
territory or domestic population of the United States ... from a threat or aggression against
the United States.” Although a deployment of National Guard troops for border security
purposes could arguably be an activity “undertaken for the military protection” of a
“domestic population,” it is unclear whether the porous nature of the border or illegal
entry of aliens is the type of “threat” or “aggression” that would be “necessary and
appropriate” for National Guard troops. The State of Arizona requested federal funds for
its National Guard under Chapter 9 for the performance of homeland defense-border
security activities.
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23 State of Arizona, Press Release, Title 32: Statutory Funding Options (Mar. 6, 2006)
[http://azgovernor.gov/dms/upload/NR_030906_%20Border%20Veto%20Legal%20Support
%20Letter.pdf].
24 Id.
25 Lowenberg, The Role of the National Guard.
26 Defense Authorization Act for Fiscal Year 2005, P.L. 108-375, Div. A, Tit. V, Subtitle B,
§§901-908.
27 32 U.S.C. §905.