What does the Posse Comitatus Act do?

• A. Restricts military personnel from enforcing civilian laws except under certain authorities
• B. Requires military personnel to enforce civilian laws whenever possible
• C. Prohibits any use of the military in civil matters
• D. Applies only to civilian police forces

Answer: (A)

The Posse Comitatus Act is about boundaries for domestic military involvement in policing. It keeps the Army and Air Force from enforcing civilian laws inside the United States unless Congress explicitly authorizes it or the Constitution provides authority. In practice, that means troops can assist civilian authorities in non-enforcement roles or under specific legal authorization, but they cannot act as police officers enforcing ordinary civilian law. Exceptions exist through mechanisms like constitutional authority or specific statutes (the Insurrection Act is the classic example), and the National Guard can be used under state control or federal authority depending on the law.