The result would be entirely unpredictable and unprincipled, a dangerous threat to American democracy. If martial law were invoked, the government would be conducted ad hoc by the president or a military commander based entirely on his or her opinion of what was needed to meet the emergency, unbound by any laws and with no transparency or public participation, and probably no accountability afterward. The fact is that there’s no guidance in the Constitution or the statutes, and only a limited historical record, to indicate what justifies a declaration of martial law. Juliette Kayyem: T rump leaves states to fend for themselves The states’ legal power to do all this is clear it is not martial law. But their role is to support, not replace, civil authorities. Guard personnel could also help enforce quarantines ordered by state governors, and even arrest violators. At least 20 state governors have now called up their National Guard to assist with delivery of food and medical supplies, clean public facilities, and adapt some of those facilities to house patients if hospitals become overwhelmed. So what would happen if, amid the panic of the coronavirus pandemic, the president tried to declare martial law? Without question, military forces directed by state governors-and perhaps even, in extreme cases, by the president-may be uniquely able to help get us through the current crisis. Nor has Congress ever tried to clarify the criteria for or limits of martial law. Kahanamoku that the statute authorizing martial law in Hawaii did not enable military trials of civilians, and it warned against the “subordination of executive, legislative and judicial authorities to complete military rule”-but it offered no further guidance about the circumstances that would justify a declaration of martial law, or about the consequences of such a declaration. In 1946, after the war ended, the Supreme Court ruled in Duncan v. Despite the fact that there was no threat of a Japanese invasion after the Battle of Midway in 1942, martial law remained in place for another two years. He also decreed a curfew and blackout, as well as a ban on the sale of alcoholic beverages-a wildly unpopular measure that was quickly reversed. The military governor, as he styled himself, immediately ordered the closure of courts, shut down schools, froze wages, suspended labor contracts, and imposed censorship of newspapers, radio, and civilian mail. The territorial governor, acting under a turn-of-the-century statute, handed the government of the Hawaiian islands over to the commander of U.S. T he last time martial law-military control of the government-was declared in the United States was December 1941, just hours after the Japanese attack on Pearl Harbor.