This article is about a United States statute prohibiting the use of the armed forces for law enforcement. For the sheriff's powers of law enforcement at common law, see posse comitatus. For the terrorist organization, see The Posse Comitatus.

The Posse Comitatus Act is a federal law of the United States (18 USC 1385) passed in 1878, after the end of Reconstruction, and was intended to prohibit Federal troops from supervising elections in former Confederate states. It generally prohibits Federal military personnel and units of the United States National Guard under Federal authority from acting in a law enforcement capacity within the United States, except where expressly authorized by the Constitution or Congress. The original act only referred to the Army, but the Air Force was added in 1956 and the Navy and Marine Corps have been included by a regulation of the Department of Defense. This law is mentioned whenever it appears that the Department of Defense is interfering in domestic disturbances.

There are a number of exceptions to the act. These include:

• National Guard units while under the authority of the governor of a state;
• Troops when used pursuant to the Federal authority to quell domestic violence as was the case during the 1992 Los Angeles riots;
• The President of the United States can waive this law in an emergency;
• In December 1981 additional laws were enacted (codified 10 USC 371-78) clarifying permissible military assistance to civilian law enforcement agencies—including 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, aircraft, intelligence, tech aid, surveillance) while generally prohibiting direct participation of DoD personnel in law enforcement (e.g., search, seizure, and arrests). For example, Coast Guard Law Enforcement Detachments (LEDETS) serve aboard Navy vessels and perform the actual boardings of interdicted suspect drug smuggling vessels and, if needed, arrest their crews.

The relevant legislation is as follows:

Sec. 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.

External link

• kuro5hin article
• Legal Affairs Essay Winner - "The Secret Posse"