The problem with talking about nationwide “martial law” is that, legally, “martial law” basically doesn’t exist. As the Brennan Center points out, the U.S. Constitution makes no mention of martial law, and doesn’t give the president — or, for that matter, anyone else — the authority to enact it. Neither Congress nor the Supreme Court is any more help here: Congress has never passed a law defining the U.S. government’s martial law powers, and the Supreme Court has never issued a ruling on whether or not the federal government has the power to enact it (though it has supported the right of states to do so). With no working legal definition of “martial law,” it’s hard to talk about what has happened under martial law, let alone what would happen in hypothetical scenarios.

Something like “martial law” has occurred dozens of times, but if you look at the various instances, it’s kind of a patchwork quilt of differing scenarios. Sometimes governors have declared it; sometimes state legislatures; sometimes Congress or the president; sometimes military generals. Sometimes the words “martial law” have been meant literally, in the sense that the military, as opposed to the civilian government, was in charge of everything now. Sometimes it’s had the looser meaning of “We’re letting the National Guard patrol the streets.” Sometimes it’s been during literal war, and sometimes it’s been to quell (often peaceful) labor strikes.