Posse Comitatus Act
The Posse Comitatus Act prohibits the direct involvement of active duty forces in assisting civilian law enforcement officials in enforcing civilian laws, except when authorized by the US Constitution or another federal statute.
The statute also prohibits active duty personnel from:
Pursuing and arresting civilians even though they have committed crimes
Any active or direct assistance to civilian law enforcement officials to enforce civilian law (such as interdiction of a vehicle, vessel, aircraft, or other similar activity; a search or seizure; an arrest, apprehension, stop and frisk, or similar activity; and use of military personnel for surveillance or pursuit of individuals, or as undercover agents, informants, investigators, or interrogators)
Three different tests have been applied by the courts to determine whether the use of military personnel has violated the Posse Comitatus Act:
Whether the action of military personnel was “active” or “passive"
Whether armed forces personnel’s involvement in the activities of civilian law enforcement officials was “pervasive"
Whether military personnel subjected citizens to the exercise of military power which was regulatory, proscriptive, or compulsory
The Act applies to the active component (Title 10) Air Force, Army, and Reserves and to the National Guard while in Title 10 status. The statute does not apply to the Coast Guard or to the National Guard while in Title 32 or State Active Duty status.
