Order Code RS22266
September 16, 2005
CRS Report for Congress
Received through the CRS Web
The Use of Federal Troops for Disaster
Assistance: Legal Issues
Jennifer K. Elsea
Legislative Attorney
American Law Division
Summary
Hurricane Katrina has raised questions concerning the President’s legal authority
to send active duty military forces into a disaster area and the permissible functions the
military can perform to protect life and property and maintain order. The Stafford Act
authorizes the use of the military for disaster relief operations at the request of the state
governor, but does not authorize the use of the military to perform law enforcement
functions, which is ordinarily prohibited by the Posse Comitatus Act. However, the
President may invoke other authorities, such as the Insurrection Act, to use federal
troops to aid in the execution of the law. This report summarizes the possible
constitutional and statutory authorities and constraints relevant to the use of armed
forces, including National Guard units in federal service, to provide assistance to states
when a natural disaster impedes the operation of state and local police.
Recognizing the risk that a standing army could pose to individual civil liberties and
the sovereignty retained by the several states, but also cognizant of the need to provide
for the defense of the nation against foreign and domestic threats, the framers of the
Constitution incorporated a system of checks and balances to divide the control of the
military between the President and Congress and to share the control of the militia with
the states. This report summarizes the constitutional and statutory authorities and
limitations relevant to the employment of the armed forces to provide disaster relief and
law enforcement assistance.
Congress has the constitutional power to raise, support, organize and regulate the
armed forces, art. I, § 8, cls. 11-14. These clauses do not expressly limit Congress as to
how, when, or where it might employ the armed forces, although presumably such use
must be in furtherance of other constitutional powers. Congress is also empowered to
provide for calling forth the militia to execute federal law and to suppress insurrections,
§ 8 cl. 15, and to provide for organizing, arming, and disciplining the militia and to
govern them when they are employed in the service of the United States, § 8, cl. 16. Once
the army is raised or the militia called forth, the President serves as their Commander-in-
Chief, art. II, § 2, cl. 1. And of course, the President is vested with the responsibility to
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to “take Care that the Laws be faithfully executed,”art. II, § 2, cl. 3. Congress has
delegated to the President the authority to use the armed forces to respond to a variety of
domestic crises, and Presidents have asserted some inherent authority to use the military
even without express statutory authorization.
Under the Constitution, states retain the primary responsibility and authority to
provide for civil order and the protection of their citizens’ lives and property. However,
the Constitution provides that the federal government is responsible for protecting the
states against invasion and insurrection, and, if the state legislature (or the governor, if the
legislature cannot be convened) requests it, protection against “domestic Violence,” art.
IV, § 4. States may not keep their own standing armies, art. I, § 10, cl.3, but they retain
the authority to call forth their militias to suppress insurrections or quell civil
disturbances, subject to any restraints imposed by the Constitution or by Congress, in the
exercise of its constitutional powers. Congress has complete authority over federal lands,
military installations, and similar areas, art. I, § 8, cl. 17.
The Posse Comitatus Act
The Constitution does not explicitly bar the use of military forces in civilian
situations or in matters of law enforcement, but the United States has traditionally
refrained from employing troops to enforce the law except in cases of necessity. The
Posse Comitatus Act, 18 U.S.C. § 1385, punishes those who, “except in cases and under
circumstances expressly authorized by the Constitution or Act of Congress, willfully use[]
any part of the Army or the Air Force as a posse comitatus or otherwise to execute the
laws. . . .”1 Questions arise most often in the context of assistance to civilian police. At
least in this context, the courts have held that, absent a recognized exception, the Posse
Comitatus Act is violated, (1) when civilian law enforcement officials make “direct active
use” of military investigators; or (2) when the use of the military “pervades the activities”
of the civilian officials; or (3) when the military is used so as to subject citizens to the
exercise of military power that is “regulatory, prescriptive, or compulsory in nature.” The
Act does not apply to the Navy or Marines,2 and does not prohibit activities conducted for
a military purpose that incidentally benefit civilian law enforcement bodies. Military
purpose encompasses activities related to base security and enforcement of the Uniform
Code of Military Justice. The Posse Comitatus Act does not apply to the National Guard
unless it is employed in federal service.
Statutory Exceptions. Congress has provided for a number of statutory
exceptions to the Posse Comitatus Act by explicitly vesting law enforcement authority
either directly in a military branch (e.g, the Coast Guard) or indirectly by authorizing the
President or another government agency to call for assistance in enforcing certain laws.3
1 See CRS Report 95-964, The Posse Comitatus Act and Related Matters: The Use of the Military
to Execute Civilian Law.
2 Department of Defense regulations effectively place them under similar constraints, and the
limitations on assistance to civilian law enforcement authorities apply to them, 10 U.S.C. § 375.
3 For a list of these authorities, see CRS Report 95-964 at ns. 63-64.

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The Insurrection Act. Congress has delegated authority to the President to call
forth the military during an insurrection or civil disturbance, 10 U.S.C. §§ 331-335.
Section 331 authorizes the President to use the military to suppress an insurrection at the
request of a state government, which is meant to fulfill the federal government’s
responsibility to protect states against “domestic violence” (although the term
“insurrection” is arguably much narrower than the phrase “domestic violence”). Section
332 delegates Congress’ power under the Constitution, art. I, § 8, cl. 14, to the President,
authorizing him to determine that “unlawful obstructions, combinations, or assemblages,
or rebellion against the authority of the United States make it impracticable to enforce the
laws of the United States” and to use the armed forces as he considers necessary to
enforce the law or to suppress the rebellion. Section 333 permits the President to use the
armed forces to suppress any “insurrection, domestic violence, unlawful combination, or
conspiracy” if law enforcement is hindered within a state, and local law enforcement is
unable to protect individuals, or if the unlawful action “obstructs the execution of the laws
of the United States or impedes the course of justice under those laws.” This section was
enacted to implement the Fourteenth Amendment and does not require the request or even
the permission of the governor of the affected state.
The Insurrection Act has been used been used to send the armed forces to quell civil
disturbances a number of times during U.S. history, most recently during the 1992 Los
Angeles riots and during Hurricane Hugo in 1989, during which wide-spread looting was
reported in St. Croix, Virgin Islands. If the President decides to respond to such a
situation, generally upon the recommendation of the Attorney General and, if necessary,
the request of the governor, he must first issue a proclamation ordering the insurgents to
disperse within a limited time, 10 U.S.C. § 334.4 If the situation does not resolve itself,
the President may issue an executive order to send in troops.5
Military Support for Law Enforcement Agencies. Congress has also
authorized the armed forces to share information and equipment with civilian law
enforcement agencies, 10 U.S.C. §§ 371-382, although prohibiting the use of armed
forces personnel to make arrests or conduct searches and seizures.
Inherent Emergency Power. Department of Defense (DoD) regulations assert
another exception that does not rest on statutory authority, but is available in very limited
circumstances and covers
Actions that are taken under the inherent right of the U.S. Government, a sovereign
national entity under the U.S. Constitution, to ensure the preservation of public order
and to carry out governmental operations within its territorial limits, or otherwise in
accordance with applicable law, by force, if necessary.6
4 See, e.g., Proclamation No. 6427, 57 Fed. Reg. 19,359 (May 1, 1992) (citing California
governor’s notification and request related to rioting in Los Angeles, and also determining that
the “domestic violence and disorder are also obstructing the execution of the laws of the United
States”); Proclamation No. 6023, 54 Fed. Reg. 39,151 (Sep. 20, 1989)(Virgin Islands).
5 See, e.g. Exec. Order No. 12804, 57 Fed. Reg. 19361 (May 1, 1992); Exec. Order No. 12690,
54 Fed. Reg. 39153 (Sep. 20, 1989).
6 U.S. Dep’t of Defense, DoD Cooperation With Civilian Law Enforcement Officials, DoD Dir.
(continued...)

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The emergency power, according to DoD directives, is available to protect federal
property and functions, and to authorize
prompt and vigorous Federal action, including use of military forces, to prevent loss
of life or wanton destruction of property and to restore governmental functioning and
public order when sudden and unexpected civil disturbances, disaster, or calamities
seriously endanger life and property and disrupt normal governmental functions to
such an extent that duly constituted local authorities are unable to control the
situation.7
Ordinarily, the implementation of such operations must be authorized by executive order,
but DoD officials and military commanders may take emergency action without prior
authorization in cases where
sudden and unexpected civil disturbances (including civil disturbances incident to
earthquake, fire, flood, or other such calamity endangering life) occur, if duly
constituted local authorities are unable to control the situation and circumstances
preclude obtaining prior authorization by the President.8
The Stafford Act
The Robert T. Stafford Disaster Relief and Emergency Assistance Act (the Stafford
Act, 42 U.S.C. §§ 5121 et seq.), authorizes the President to make a wide range of federal
aid available to states that are stricken by a natural or man-made disaster.9 It provides
statutory authority for employing the U.S. armed forces for domestic disaster relief.
Permitted operations include debris removal and road clearance, search and rescue,
emergency medical care and shelter, provision of food, water, and other essential needs,
dissemination of public information and assistance regarding health and safety measures,
and the provision of technical advice to state and local governments on disaster
management and control. The authority does not constitute an exception to the Posse
Comitatus Act. In the event of a disaster that results in the wide-scale deterioration of civil
law and order, the authority to employ active duty troops to perform law enforcement
functions must be found elsewhere. The Stafford Act does not authorize the use of federal
military forces to maintain law and order. Federal forces would have no authority, for
example, to act as traffic controllers or provide security for facilities used in the relief
efforts, unless such activities serve a valid military purpose. Patrolling in civilian
neighborhoods for the purpose of providing security from looting and other activities,
would not be permissible, although patrolling for humanitarian relief missions, such as
rescue operations and food delivery (which may have the incidental benefit of deterring
crime) would not violate the Posse Comitatus Act.
6 (...continued)
5525.5 (Encl. 4) § E4.1.2.3 (1989).
7 Id.
8 U.S. Dep’t of Defense, Military Assistance for Civil Disturbances, DoD Dir. 3025.12 § 4.2.2.
(1994).
9 For an overview of the Stafford Act, see CRS Report RL33053, Federal Stafford Act Disaster
Assistance: Presidential Declarations, Eligible Activities, and Funding.

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Military resources may be employed in the following situations.
Essential Assistance (10-Day Authority). Upon the request of the governor,
the President may task the Department of Defense to provide any emergency work the
President deems essential for the preservation of life and property in the immediate
aftermath of an incident that may ultimately qualify for assistance under a declaration.
Such assistance is available for up to ten days before a presidential declaration of an
emergency or a major disaster is issued, 42 U.S.C. § 5170b(c). Emergency work can
include the clearance and removal of debris and wreckage and the restoration of essential
public facilities and services, 42 U.S.C. § 5170(c)(6)(B). The provision is designed to be
utilized in instances where communications problems impede the ability to meet the
prerequisites for declaring an emergency or major disaster or the ability to coordinate the
work through FEMA.
Emergency. Unless the President determines that a disaster implicates
preeminently federal interests, the declaration of an emergency under the Stafford Act
requires that the governor of the affected state first make a determination that the situation
is of such severity and magnitude that the state is unable to respond effectively without
federal assistance, which determination must include a detailed definition of the type and
amount of federal aid required, 42 U.S.C. § 5191. The governor must also implement the
state’s emergency response plan, for example, by activating the state’s National Guard
units under state control (in which case the Posse Comitatus Act does not apply to them),
and provide information regarding the resources that have been committed.
Major Disaster. The prerequisites for a major disaster declaration are similar to
those for an emergency, 42 U.S.C. § 5170. The governor must first execute the state’s
emergency plan and make a determination that state capabilities are insufficient to deal
with the circumstances. However, the governor need not specify which forms of
assistance are needed. The governor must provide information regarding the resources
that have been committed and certify that the state will comply with cost sharing
provisions under the Stafford Act. There is no provision for the declaration of a major
disaster without the governor’s request. If the governor activates Guard units and keeps
them under state control, those units are not restricted by the Posse Comitatus Act. If the
state’s National Guard units are called into federal service to respond to an emergency or
a major disaster, their role is statutorily restricted to the disaster relief operations
authorized under the Stafford Act.
Immediate Response Authority
DoD doctrine allows commanders to provide resources and assistance to civil
authorities without or prior to a declaration under the Stafford Act when a disaster
overwhelms the capabilities of local authorities and necessitates immediate action “to
prevent human suffering, save lives, or mitigate great property damage.”10 Immediate
response actions can include the types of activities authorized under the Stafford Act,
including, at the request of civil authorities, rescue, evacuation, and emergency medical
treatment, restoration of essential public services, debris removal, controlling
contaminated areas, safeguarding and distributing food and essential supplies, and
10 U.S. Dep’t of Defense, Military Support to Civil Authorities, DoD Dir. 3025.1 § 4.5 (1993).

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supplying interim emergency communications.11 The immediate response authority may
also include law enforcement activities that would ordinarily be prohibited by the Posse
Comitatus Act. The controlling directive does not require a request from state or local
officials, but states that
DoD Components shall not perform any function of civil government unless
absolutely necessary on a temporary basis under conditions of Immediate Response.
Any commander who is directed, or undertakes, to perform such functions shall
facilitate the reestablishment of civil responsibility at the earliest time possible.12
The immediate response authority is not provided for in any statute, but is said to
have deep historical roots.13 The 1906 San Francisco earthquake and fire are noted
examples. There, the commanding general of the Pacific Division, on his own initiative,
deployed all troops at his disposal to assist civil authorities to stop looting, protect federal
buildings, and to assist firefighters.14
11 Id. § 4.5.1.
12 Id. § 4.4.10.
13 For a discussion of instances when the emergency, “immediate response authority” has been
used see, Cmdr. Jim Winthorp, The Oklahoma City Bombing: Immediate Response Authority and
Other Military Assistance to Civil Authority (MAC), ARMY LAW. 3 (July, 1997).
14 Id at 5.

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