Under the Posse Comitatus Act, Title 10 forces may be used in domestic law enforcement only if explicitly authorized by what?

• A. The US Constitution (rebellion) or an Act of Congress
• B. A presidential order
• C. A state governor's proclamation
• D. An international treaty

Answer: (A)

The rule is that federal troops can't be used to enforce civilian law at home unless there is explicit authority from the Constitution or from Congress. So, Title 10 forces may be deployed domestically only when the Constitution provides authority in cases of rebellion or insurrection, or when Congress has enacted a law that authorizes such use (for example, the Insurrection Act). A presidential order by itself doesn’t grant this authority, and a state governor’s proclamation or an international treaty wouldn’t remove the general restriction. The essential point is that clear constitutional or statutory authorization is required before the military can participate in domestic law enforcement.