An arcane but extraordinary authority
The Insurrection Act is a statutory exception to the Posse Comitatus Act that allows the use of military and federalized National Guard to support law enforcement officers when they are overwhelmed or to quell an uprising; the use of the military for domestic law enforcement is otherwise prohibited under Posse Comitatus. Presidents have used this arcane but extraordinary authority sparingly in recent decades. Yet it is clear now that norms with respect to its modern use rely too heavily on the character and whims of the incumbent in the Oval Office—regardless of political party.
The Insurrection Act gives the president authority to use active-duty and federalized National Guard regardless of the consent of governors and local officials if the president believes that the law cannot be upheld in circumstances of domestic unrest, rebellion, or insurrection. The act is surprisingly vague and places few constraints on presidential authority over when and how it can be used. Its use over the course of American history has varied under different circumstances and leaders, from helping enforce desegregation in the 1950s to quelling the Rodney King riots in Los Angeles in 1992—its last use, undertaken at the request of the California governor. Continue reading.