President Trump threatened to invoke the Insurrection Act to put down the riots occurring after the death of George Floyd in police custody. The President said, "If a city or a state refuses to take the actions that are necessary to defend the life and property of their residents, then I will deploy the United States military and quickly solve the problem for them." He hasn’t done it yet and the question is: would it be constitutional?
The U.S. Constitution is mostly silent on the question of presidential emergency powers and martial law. Article I, Section 9 allows habeas corpus to be suspended “in Cases of Rebellion or Invasion” when the public safety requires it. We’re not being invaded and the current circumstances fall short of a full-fledged rebellion. Abraham Lincoln suspended the writ of habeas corpus, but there was an actual civil war going on at the time.
That’s it for the text of the Constitution. Now let’s look at federal statutes. The Posse Comitatus Act was passed in 1878 to prevent the use of the U.S. military to enforce domestic policy inside the United States. However, the Act is subject to the provisions of the Insurrection Act of 1807 and its later revisions.
The Insurrection Act, as amended, authorizes the President to use military and National Guard troops within the United States:
The Insurrection Act has been invoked at least 20 times - first in conflicts with Native Americans, then labor conflicts, slave rebellions, to suppress the Ku Klux Klan, to desegregate public schools in Little Rock in 1957, to put down riots in D.C., Chicago, and elsewhere in the late ‘60s, as well as the Los Angeles riots of 1992. George W. Bush wanted to use the Act to intervene after Hurricane Katrina when the governor of Louisiana refused to ask for help, but did not. The Act was changed in 2007 to allow the use of the military without state consent in emergencies, but that was quickly repealed after all 50 governors objected.
Alan Dershowitz wrote about using the Act in the circumstances we are in today:
I’m not so sure the same pattern would hold today. Consider the following scenario: Trump issues a proclamation he will use the Insurrection Act and send troops if rioters don’t disperse. Former President Obama immediately gets on a plane to visit his friend, the federal judge in Hawaii, who issues a nationwide injunction against the use of the Insurrection Act in a case he cooks up with the ACLU. The generals at the Pentagon immediately voice their approval of the Hawaii judge’s action. Where would we be then? Uncharted waters in uncharted territory in an uncharted universe.
Maybe it’s better to let the governors take the lead in this, after all. I must confess, though, that I do like the idea of not allowing federal money to be spent to repair the damage the riots cause in states where the governors decline to ask for the National Guard to be sent in. If they want to stand down, defund the police, abolish their police departments, and try to make friends with bears, the consequences should be on their dime, not mine.