The Posse Comitatus Act and Related Matters: A Sketch

Summary

The Posse Comitatus Act states that “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.” 18 U.S.C. §1385. It reflects an American tradition that bridles at military involvement in civilian affairs. Congress, however, has approved a number of instances where extraordinary circumstances warrant a departure from the general rule, particularly in cases where the armed forces provide civilian assistance without becoming directly involved in civilian law enforcement. This is an abridged version of CRS Report R42659, The Posse Comitatus Act and Related Matters: The Use of the Military to Execute Civilian Law, in which the authorities for the statements made here may be found.