Posse Comitatus Act
The Posse Comitatus Act is the United States federal law (18 U.S.C. § 1385, original at 20 Stat. 152) that was passed on June 18, 1878, after the end of Reconstruction and was updated in 1981. Its intent (in concert with the Insurrection Act of 1807) was to limit the powers of Federal government in using federal military personnel to enforce the State laws.
The Bill/Act as modified in 1981 refers to the Armed Forces of the United States. It does not apply to the National Guard under state authority from acting in a law enforcement capacity within its home state or in an adjacent state if invited by that state's governor. The U.S. Coast Guard, which operates under the Department of Homeland Security, is also not covered by the Posse Comitatus Act, primarily because the Coast Guard has both a maritime law enforcement mission and a federal regulatory agency mission.
The Act, § 15 of the appropriations bill for the Army for 1879, found at 20 Stat. 152, was a response to, and subsequent prohibition of, the military occupation by U.S. Army troops of the former Confederate States during the ten years of Reconstruction (1867–1877) following the American Civil War (1861–1865). The U.S. withdrew federal troops from Southern states as a result of a compromise in one of the most disputed national elections in American history, the 1876 U.S. presidential election. Samuel J. Tilden of New York, the Democratic candidate, defeated Republican candidate Rutherford B. Hayes of Ohio in the popular vote. Tilden garnered 184 electoral votes to Hayes' 165; 20 disputed electoral votes remained uncounted. After a bitter fight, Congress struck a deal resolving the dispute and awarding the presidency to Hayes.
In return for Southern acquiescence regarding Hayes, Republicans agreed to support the withdrawal of federal troops from the former Confederate states, ending Reconstruction. Known as the Compromise of 1877, South Carolina, Florida and Louisiana agreed to certify Rutherford B. Hayes as the President in exchange for the removal of Federal troops from the South. The U.S. Constitution places primary responsibility for the holding of elections in the hands of the individual states. The maintenance of peace, conduct of orderly elections, and prosecution of unlawful actions are all state responsibilities, pursuant of any state's role of exercising police power and maintaining law and order, whether part of a wider federation or a unitary state.
During the local, state, and federal elections of 1874 and 1876 in the former Confederate states, all levels of government chose not to exercise their police powers to maintain law and order. Many acts of violence, and a suppression of the vote of some political and racial groups, resulted in the election of state legislators and U.S. congressmen who halted and reversed political reform in the American South.
When the U.S. Representatives and Senators from the former Confederate states reached Washington, they set as a priority the creation of a statute prohibiting any future President or Congress from directing, by military order or federal legislation, the imposition of federal troops in any U.S. state.
An exception to Posse Comitatus Act derived from the Force Acts allowed President Eisenhower to send federal troops into Little Rock, Arkansas, during the 1958 school desegregation crisis. The Force Acts, among other powers, allow the President to call up military forces when state authorities are either unable or unwilling to suppress violence that is in opposition to the constitutional rights of the people.
The original Posse Comitatus Act referred essentially to the United States Army. The Air Force was added in 1956 and the Navy and the Marine Corps have been included by a regulation of the Department of Defense. The United States Coast Guard is not included in the Act. (The U.S. Coast Guard was originally part of the Treasury Department, was later part of the Department of Transportation, and is now within the Department of Homeland Security.) This law is often relied upon to prevent the Department of Defense from interfering in domestic law enforcement.
The original provision was enacted as Section 15 of chapter 263, of the Acts of the 2nd session of the 45th Congress.
Sec. 15. From and after the passage of this act it shall not be lawful to employ any part of the Army of the United States, as a posse comitatus, or otherwise, for the purpose of executing the laws, except in such cases and under such circumstances as such employment of said force may be expressly authorized by the Constitution or by act of Congress ; and no money appropriated by this act shall be used to pay any of the expenses incurred in the employment of any troops in violation of this section and any person willfully violating the provisions of this section shall be deemed guilty of a misdemeanor and on conviction thereof shall be punished by fine not exceeding ten thousand dollars or imprisonment not exceeding two years or by both such fine and imprisonment
The text of the relevant legislation is as follows:
- 18 U.S.C. § 1385. Use of Army and Air Force as posse comitatus
- Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.
Also notable is the following provision within Title 10 of the United States Code (which concerns generally the organization and regulation of the armed forces and Department of Defense):
- 10 U.S.C. § 375. Restriction on direct participation by military personnel
- The Secretary of Defense shall prescribe such regulations as may be necessary to ensure that any activity (including the provision of any equipment or facility or the assignment or detail of any personnel) under this chapter does not include or permit direct participation by a member of the Army, Navy, Air Force, or Marine Corps in a search, seizure, arrest, or other similar activity unless participation in such activity by such member is otherwise authorized by law.
Recent legislative events 
On September 26, 2006, President Bush urged Congress to consider revising federal laws so that U.S. armed forces could restore public order and enforce laws in the aftermath of a natural disaster, terrorist attack or incident, or other condition.
These changes were included in the John Warner National Defense Authorization Act for Fiscal Year 2007 (H.R. 5122), which was signed into law on October 17, 2006.
Section 1076 is titled "Use of the Armed Forces in major public emergencies." It provided that:
The President may employ the armed forces... to... restore public order and enforce the laws of the United States when, as a result of a natural disaster, epidemic, or other serious public health emergency, terrorist attack or incident, or other condition... the President determines that... domestic violence has occurred to such an extent that the constituted authorities of the State or possession are incapable of maintaining public order... or [to] suppress, in a State, any insurrection, domestic violence, unlawful combination, or conspiracy if such... a condition... so hinders the execution of the laws... that any part or class of its people is deprived of a right, privilege, immunity, or protection named in the Constitution and secured by law... or opposes or obstructs the execution of the laws of the United States or impedes the course of justice under those laws.
In 2008, these changes in the Insurrection Act of 1807 were repealed in their entirety, reverting to the previous wording of the Insurrection Act that in its original form was written to limit Presidential power as much as possible in the event of insurrection, rebellion, or lawlessness.
In 2011, U.S. President Barack Obama signed National Defense Authorization Act for Fiscal Year 2012 into law. Section 1031, clause "b", article 2 defines a 'covered person', i.e., someone possibly subject to martial law, as the following: "A person who was a part of or substantially supported al-Qaeda, the Taliban, or associated forces that are engaged in hostilities against the United States or its coalition partners, including any person who has committed a belligerent act or has directly supported such hostilities in aid of such enemy forces." 
Exclusions and limitations 
There are a number of situations in which the Act does not apply. These include:
- National Guard units and state defense forces while under the authority of the governor of a state;
- Troops used under the order of the President of the United States pursuant to the Insurrection Act, as was the case during the 1992 Los Angeles Riots.
- Under 18 U.S.C. § 831, the Attorney General may request that the Secretary of Defense provide emergency assistance if civilian law enforcement is inadequate to address certain types of threats involving the release of nuclear materials, such as potential use of a nuclear or radiological weapon. Such assistance may be by any personnel under the authority of the Department of Defense, provided such assistance does not adversely affect U.S. military preparedness. The only exemption is nuclear materials.
- Support roles under the Joint Special Operations Command
Exclusion applicable to U.S. Coast Guard 
- See the Law Enforcement Detachments and Missions of the United States Coast Guard for more information on U.S. Coast Guard law enforcement activities.
Although it is a military force, the U.S. Coast Guard, which operates under the Department of Homeland Security, is not restricted by the Posse Comitatus Act. The Coast Guard enforces federal laws within its jurisdiction, even when operating as a service for the U.S. Navy.
In December 1981, additional laws were enacted clarifying permissible military assistance to civilian law enforcement agencies and the Coast Guard, especially in combating drug smuggling into the United States. Posse Comitatus clarifications emphasize supportive and technical assistance (e.g., use of facilities, vessels, and aircraft, as well as intelligence support, technological aid, and surveillance) while generally prohibiting direct participation of Department of Defense personnel in law enforcement (e.g., search, seizure, and arrests). For example, a U.S. Navy vessel may be used to track, follow, and stop a vessel suspected of drug smuggling, but Coast Guard Law Enforcement Detachments (LEDETs) embarked aboard the Navy vessel would perform the actual boarding and, if needed, arrest the suspect vessel's crew.
Federal military forces have a long history of domestic roles, including the occupation of sovereign Southern states during Reconstruction. The Posse Comitatus Act prohibits the use of federal military forces to "execute the laws"; however, there is disagreement over whether this language may apply to troops used in an advisory, support, disaster response, or other homeland defense role, as opposed to conventional law enforcement.
On March 10, 2009, active duty U.S. Army Military Police troops from Fort Rucker were deployed to Samson, Alabama, in response to a murder spree. Samson officials confirmed that the soldiers assisted in traffic control and securing the crime scene. The governor of Alabama did not request military assistance nor did President Obama authorize their deployment. Subsequent investigation found that the Posse Comitatus Act was violated and several military members received "administrative actions".
Drone training 
Unarmed USAF drone aircraft routinely track American civilian auto traffic as training exercises to prepare for later missions.
See also 
- Martial law
- List of military actions by or within the United States
- United States Northern Command
- Military Cooperation with Civilian Law Enforcement Agencies Act
- Operation Garden Plot
||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (December 2008)|
- The Posse Comitatus Act: Setting the record straight on 124 years of mischief and misunderstanding before any more damage is done, Military Law Review, Vol. 175, 2003.
- Lieberman, Jethro (1999). A practical companion to the Constitution: how the Supreme Court has ruled on issues from abortion to zoning. University of California Press. ISBN 0-520-21280-0.
- http://www.nytimes.com/2009/07/25/us/25detain.html?scp=3&sq=Posse%20Comitatus%20Act%20of%201878&st=cse Mazzetti, Mark and Johnston, David. Bush Weighed Using Military in Arrests. New York Times, July 24, 2009.
- Text at Wikisource
- John Warner National Defense Authorization Act for Fiscal Year 2007
- H.R. 5122, pp. 322–323
- "H.R. 4986: National Defense Authorization Act for Fiscal Year 2008". GovTrack.us. 2008. Retrieved January 24, 2008.
- About the United States Coast Guard
- http://www.uscg.mil/History/articles/LEDET_History.asp Coast Guard Law Enforcement Detachments (LEDETs): A History
- Army reviews shows troop use in Samson killing spree violated federal law>, Birmingham News
- Revolutionizing Northern Command, Lt. Col. Gary L. McGinniss, U.S. Army
- Clemons, Steve. "Air Force Drones Trail Civilian Auto Traffic in New Mexico." The Atlantic, 6 July 2012.
-  – Bill Text 112th Congress (2011–2012) S.1867.ES
Hendell, Garri B. "" "Domestic Use of the Armed Forces to Maintain Law and Order – posse comitatus Pitfalls at the Inauguration of the 44th President" Publius (2011) 41(2): 336–348 first published online May 6, 2010 doi:10.1093/publius/pjq014
Lindorff, David. "Could It Happen Here?". Mother Jones magazine, April 1988.
- 18 U.S.C. § 1385 – Use of Army and Air Force as Posse Comitatus
- The Posse Comitatus Act: A Principle in Need of Renewal, Washington University Law Quarterly Vol 75 No. 2
- Mold, Mildew, and the Military Role in Disaster Response, JURIST
- John Warner National Defense Authorization Act for Fiscal Year 2007
- Text of H.R. 5122
-  – Bill Text 112th Congress (2011–2012) S.1867.ES
-  – Federalist Paper #29 Concerning the Militia, Alexander Hamilton, pub. 10-January-1788