Which act prohibits the use of federal troops for law enforcement operations?

The Posse Comitatus Act is significant because it establishes the principle that federal military forces may not be used to enforce domestic laws, thereby restricting their involvement in law enforcement operations. This act originated from post-Civil War era legislation intended to limit the use of troops for policing functions and civilian law enforcement, aiming to prevent the military from exerting excessive control over civilian affairs.

The essence of the Posse Comitatus Act is to protect civil liberties by maintaining a clear separation between military authority and civil law enforcement, ensuring that law enforcement remains primarily the responsibility of civilian agencies. This is crucial in preserving democratic principles and preventing potential abuses of power by the military.

In contrast, the Insurrection Act allows the President to deploy federal troops to suppress insurrections and enforce law and order under specific circumstances. The National Defense Authorization Act primarily deals with defense policy and funding for the military but does not specifically prohibit the use of troops for law enforcement. Lastly, the Military Support to Civil Authorities Act outlines scenarios under which military forces can assist civilian authorities but does not negate the restrictions placed by the Posse Comitatus Act.