Posse Comitatus Act
The Posse Comitatus Act is a US federal law that was enacted in 1878 after the end of Reconstruction . It originally prohibited federal troops from monitoring elections in the former Confederate states. Even today, the Posse Comitatus Act prevents the military from enforcing law and order like the police - unless the Constitution or Congress allow exceptions.
The original law of 1878 only affected the United States Army, the US Army . The Air Force was added to the 1956 Act, and the US Navy and Marine Corps were also placed under the Posse Comitatus Act by a Department of Defense decree .
The National Guard is exempt from these regulations if it is acting under the orders of the governor . There are also exceptions for the Coast Guard and other forces, such as the Joint Interagency Task Force ( Naval Air Station , Key West , Florida ), which deals with the prevention of drug trafficking, and an approach based on the Insurrection Act of 1807.