U.S. Military Deployment on U.S. Soil

Key Points

• 1Military troops are barred from civilian law enforcement under the Posse Comitatus Act (1878), unless authorized by the Constitution or an Act of Congress.
• 2The Insurrection Act permits the President to deploy the military during civil unrest.
• 3U.S. Presidents have long deployed the national guard for civil unrest, but federalizing to support law enforcement directly against protests began in 1967.
• 4President Donald Trump deployed about 4,000 national guard troops and 700 marines in response to protests.
• 5Article 355 of the Indian Constitution mandates the Union to protect States against “external aggression” and “internal disturbance”.