🔗 Posse Comitatus Act

🔗 United States 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Law Enforcement

The Posse Comitatus Act is a United States federal law (18 U.S.C. § 1385, original at 20 Stat. 152) signed on June 18, 1878, by President Rutherford B. Hayes. The purpose of the act – in concert with the Insurrection Act of 1807 – is to limit the powers of the federal government in using federal military personnel to enforce domestic policies within the United States. It was passed as an amendment to an army appropriation bill following the end of Reconstruction and was updated in 1956 and 1981.

The act specifically applies only to the United States Army and, as amended in 1956, the United States Air Force. Although the act does not explicitly mention the United States Navy and the United States Marine Corps, the Department of the Navy has prescribed regulations that are generally construed to give the act force with respect to those services as well. The act does not prevent the Army National Guard or the Air 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 United States Coast Guard (under the Department of Homeland Security) and United States Space Force (under the Department of the Air Force) are not covered by the Posse Comitatus Act either, primarily because although both are armed services, they also have maritime and space law enforcement missions respectively.

The title of the act comes from the legal concept of posse comitatus, the authority under which a county sheriff, or other law officer, conscripts any able-bodied person to assist in keeping the peace.