The 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. 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. forces there. 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. 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. 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.

In 1946, after the war ended, the Supreme Court ruled in Duncan v. 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. Nor has Congress ever tried to clarify the criteria for or limits of martial law.

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. 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. Guard personnel could also help enforce quarantines ordered by state governors, and even arrest violators. But their role is to support, not replace, civil authorities. The states’ legal power to do all this is clear; it is not martial law.

[Juliette Kayyem: T]rump leaves states to fend for themselves

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. 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 result would be entirely unpredictable and unprincipled, a dangerous threat to American democracy.

The prospect of martial law, while still remote, is not purely hypothetical in the current crisis. Donald Trump has called himself a “wartime president.” His likely Democratic opponent in November, Joe Biden, describes efforts to stem the pandemic as “akin to war.” And last week Gavin Newsom, the governor of California, suggested that martial law is not necessary “at this moment”—implying that it may yet be considered. In a time of panic, statements like this naturally lead to questions about the authority of the president or state governors to deploy troops at home. Aware that the specter of martial law has arisen, Peter Gaynor, the head of FEMA, was at pains during the White House Coronavirus Task Force press conference on Sunday to emphasize that the use of the National Guard to help with the emergency “is not martial law.” And when Defense Secretary Mark Esper confirmed on Monday that President Trump had activated the National Guard in three states through Title 32—under which the state governors control the troops while the federal government pays for them—he emphasized that “this is not a move toward martial law, as some have claimed.”

The president’s powers to use federal troops (or National Guard forces called to active duty) are more limited than governors’. The president has announced that the Navy will use its two hospital ships to provide needed hospital beds, and the Defense Department has said that it will share critical medical supplies—ventilators, masks, and other protective gear—with civilian health-care workers. New York Governor Andrew Cuomo has also asked the Army Corps of Engineers to provide additional hospital beds for the acutely ill. What federal military forces may not legally do, however, is engage in law enforcement, except by following statutory procedures to suppress an insurrection, violent civil unrest, or an unlawful combination or conspiracy. The law says that job is left to state and local police and National Guard personnel, even in an emergency like the one we now face.

It’s true that federal troops have been deployed domestically a number of times in our recent history: to help integrate the Little Rock schools in 1954; to restore order following the killing of Dr. Martin Luther King Jr. in 1968; and to quell the violence in Los Angeles after the Rodney King verdict in 1992. But all of these deployments were authorized by statute—and all were used to support, not supplant, the law.

[Craig R. McKinley and James Winnefeld: The right way to activate the National Guard]

Yet as the crisis mounts, some worry that governors or the president might declare martial law, using soldiers to replace civilian government for a time, and with it the rule of law. Given his amply demonstrated predilection for breaking with long-established norms, Trump, if confronted with the “worst-case scenario” he has referred to, might be tempted to invoke martial law to free himself to act without legal constraints, using it to postpone or call off the November election, close down critical media, take control of medical supplies and food, or curtail travel. Nevertheless, under any conceivable circumstances growing out of the current crisis, a declaration of martial law would represent a flagrant abuse of the president’s power. America’s experience with martial law makes this clear.

Although martial law has been invoked in this country only rarely, the concept was well known to this nation’s founders. Although its use had long been barred by the British Parliament, martial law had been imposed in Boston and in Virginia during the American Revolution, and the great English legal scholar William Blackstone, on whom the Founders relied heavily, described martial law as “no law, but as something indulged rather than allowed as law.” Still, no record exists of the Framers having discussed martial law at the Constitutional Convention. Early Congresses passed several laws allowing the deployment of state militias and federal troops in emergencies—but only to help enforce the law, not displace it.

Martial law was first invoked in the young nation during the War of 1812 by General Andrew Jackson in New Orleans. Laws “must sometimes be silent,” he wrote, “when necessity speaks.” But despite Jackson’s heroic defense of the city against the British, his suspension of civilian government there—which continued even after the war officially ended—was widely criticized as unnecessary.

State or territorial officials also declared martial law several times in the early days of the Republic. When a full-fledged revolt broke out against the Rhode Island government in the Dorr Rebellion, in 1841, the Supreme Court in Luther v. Borden approved the imposition of martial law, saying that the Court would not question the state’s authority. One justice dissented vehemently, however, warning that under martial law “every citizen, instead of reposing under the shield of known and fixed laws as to his liberty, property, and life, exists with a rope round his neck, subject to be hung up by a military despot at the next lamp-post, under the sentence of some drum-head court-martial.”

During the Civil War, President Lincoln declared martial law with regard specifically to “rebels and insurgents” and certain other disloyal individuals. Although Lincoln limited the application of martial law (it did not apply to the general population), in 1866 the Supreme Court ruled, in a case called Ex parte Milligan, that his order to try such persons by military commission was illegal where civilian courts remained open and operating.

In its decision, the Court laid out criteria for invocation of martial law:

If, in foreign invasion or civil war, the courts are actually closed, and it is impossible to administer criminal justice according to law, then, on the theatre of active military operations, where war really prevails, there is a necessity to furnish a substitute for the civil authority, thus overthrown, to preserve the safety of the army and society; and as no power is left but the military, it is allowed to govern by martial rule until the laws can have their free course.

And, the Court said, “As necessity creates the rule, so it limits its duration.” The Court warned of allowing this extraordinary measure under other circumstances: “Civil liberty and this kind of martial law cannot endure together; the antagonism is irreconcilable; and, in the conflict, one or the other must perish.”

[Elizabeth Goitein: The alarming scope of the president’s emergency powers]

The Court apparently failed to consider the possibility that the courts might be closed by military order. In such a case, of course, no one would be left to judge the legitimacy of the military’s actions.

The objective criteria set out by the Court—the presence of war, actual insurrection or invasion, effective closure of courts, displacement of civil authorities, and no alternative to protect the Army and society—left plenty of room for judgment about when martial law could be proclaimed. Yet they revealed the kind of extreme conditions that might justify its use.

Martial law was declared a number of times in the late nineteenth and early twentieth centuries at the state level, by governors acting as commanders in chief of their militias or national guards. Most often the declarations resulted from labor disputes. In a 1903 miners’ strike, for example, Colorado Governor James Peabody declared martial law in San Miguel County, where Telluride is located. He closed the saloons, imposed a curfew, censored the press, collected guns, and suspended habeas corpus, although the civil courts remained open. He also ordered state troops to arrest and detain Charles Moyer, the president of the Western Federation of Miners. In the Supreme Court’s 1909 decision in Moyer v. Peabody, Justice Oliver Wendell Holmes upheld the legality of Peabody’s use of martial law, writing that “the governor’s declaration that a state of insurrection existed is conclusive of that fact … When it comes to a decision by the head of the state upon a matter involving its life, the ordinary rights of individuals must yield to what he deems the necessities of the moment.”

In 1932, however, the Court reversed course when Texas Governor Ross Sterling declared martial law in several counties. The governor claimed that he was acting to quell an insurrection, but his real purpose was to halt oil and gas production, in an effort to arrest falling prices caused by an oversupply of petroleum. He argued that “the court was powerless … to intervene,” and that his order had the quality of a “supreme and unchallengeable edict.” But in Sterling v. Constantin, a unanimous Court struck down the declaration, concluding that otherwise “the fiat of a state Governor, and not the Constitution of the United States, would be the supreme law of the land … Under our system of government, such a conclusion is obviously untenable.” How to challenge the legitimacy of a declaration? “What are the allowable limits of military discretion,” the Court wrote, “and whether or not they have been overstepped in a particular case, are judicial questions.” Still, the Court offered no new clues about when martial law might be justified.

Over the years, the Department of Defense has issued various statements and regulations that emphasize (as one 1960 Army lecture had it) the idea that civilian deference to military authority is “repulsive to the American concept of government.” A 1941 War Department field manual declared, channeling the Supreme Court’s decision in Ex Parte Milligan, that martial law could be invoked only when “the machinery of the civil government has broken down, and the courts are no longer properly and unobstructedly exercising their jurisdiction.” (And when it is invoked, “the civil and criminal laws continue in force, except insofar as their actual enforcement may be suspended for the time being by inability of the civil authorities to function, or in specific particulars, as a matter of military necessity, by order of the President or of the military commander acting by authority of the President.”) A more recent Defense Department regulation stated,

Martial law depends for its justification upon public necessity. Necessity gives rise to its creation; necessity justifies its exercise; and necessity limits its duration. The extent of the military force used and the actual measures taken, consequently, will depend upon the actual threat to order and public safety which exists at the time. In most instances the decision to impose martial law is made by the President … However, the decision to impose martial law may be made by the local commander on the spot, if the circumstances demand immediate action, and time and available communications facilities do not permit obtaining prior approval from higher authority.

But this regulation was inexplicably removed in 2008 and not replaced, so current military rules pertaining to martial law are not known.

In the absence of any further clarification from the courts, or from Congress, or even from the military itself, we cannot rule out the possibility that in an acute domestic crisis like the one we face now, the president or a military commander might, like Lincoln or Jackson, decide to take matters into their own hands. Any court test of these actions would almost certainly be retrospective, if it occurred at all. Even if courts continued operating during military rule, judges have always been reluctant to second-guess the military, especially during wartime.

[Read: This is how Donald Trump will be remembered]

But Trump’s “wartime president” rhetoric notwithstanding, invocation of martial law would be utterly unjustified and lawless. The coronavirus threatens the health of many citizens, and it may wreck the economy. But civilian government is adapting to the crisis. Courts remain open and operating, with modified procedures. And there has been no hint of insurrection, no widespread lawbreaking or domestic unrest. None of the conditions used to justify martial law in the past are present today or are likely to arise.

Not long ago a top civilian official in the Pentagon declared, “Our goal is not to declare martial law and take control. Our goal is to avoid that at all costs.” His statement reflects our understanding that martial law would threaten not only civil liberties but also democracy itself.

The 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. 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. forces there. 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. 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. 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.

In 1946, after the war ended, the Supreme Court ruled in Duncan v. 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. Nor has Congress ever tried to clarify the criteria for or limits of martial law.

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. 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. Guard personnel could also help enforce quarantines ordered by state governors, and even arrest violators. But their role is to support, not replace, civil authorities. The states’ legal power to do all this is clear; it is not martial law.

[Juliette Kayyem: T]rump leaves states to fend for themselves

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. 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 result would be entirely unpredictable and unprincipled, a dangerous threat to American democracy.

The prospect of martial law, while still remote, is not purely hypothetical in the current crisis. Donald Trump has called himself a “wartime president.” His likely Democratic opponent in November, Joe Biden, describes efforts to stem the pandemic as “akin to war.” And last week Gavin Newsom, the governor of California, suggested that martial law is not necessary “at this moment”—implying that it may yet be considered. In a time of panic, statements like this naturally lead to questions about the authority of the president or state governors to deploy troops at home. Aware that the specter of martial law has arisen, Peter Gaynor, the head of FEMA, was at pains during the White House Coronavirus Task Force press conference on Sunday to emphasize that the use of the National Guard to help with the emergency “is not martial law.” And when Defense Secretary Mark Esper confirmed on Monday that President Trump had activated the National Guard in three states through Title 32—under which the state governors control the troops while the federal government pays for them—he emphasized that “this is not a move toward martial law, as some have claimed.”

The president’s powers to use federal troops (or National Guard forces called to active duty) are more limited than governors’. The president has announced that the Navy will use its two hospital ships to provide needed hospital beds, and the Defense Department has said that it will share critical medical supplies—ventilators, masks, and other protective gear—with civilian health-care workers. New York Governor Andrew Cuomo has also asked the Army Corps of Engineers to provide additional hospital beds for the acutely ill. What federal military forces may not legally do, however, is engage in law enforcement, except by following statutory procedures to suppress an insurrection, violent civil unrest, or an unlawful combination or conspiracy. The law says that job is left to state and local police and National Guard personnel, even in an emergency like the one we now face.

It’s true that federal troops have been deployed domestically a number of times in our recent history: to help integrate the Little Rock schools in 1954; to restore order following the killing of Dr. Martin Luther King Jr. in 1968; and to quell the violence in Los Angeles after the Rodney King verdict in 1992. But all of these deployments were authorized by statute—and all were used to support, not supplant, the law.

[Craig R. McKinley and James Winnefeld: The right way to activate the National Guard]

Yet as the crisis mounts, some worry that governors or the president might declare martial law, using soldiers to replace civilian government for a time, and with it the rule of law. Given his amply demonstrated predilection for breaking with long-established norms, Trump, if confronted with the “worst-case scenario” he has referred to, might be tempted to invoke martial law to free himself to act without legal constraints, using it to postpone or call off the November election, close down critical media, take control of medical supplies and food, or curtail travel. Nevertheless, under any conceivable circumstances growing out of the current crisis, a declaration of martial law would represent a flagrant abuse of the president’s power. America’s experience with martial law makes this clear.

Although martial law has been invoked in this country only rarely, the concept was well known to this nation’s founders. Although its use had long been barred by the British Parliament, martial law had been imposed in Boston and in Virginia during the American Revolution, and the great English legal scholar William Blackstone, on whom the Founders relied heavily, described martial law as “no law, but as something indulged rather than allowed as law.” Still, no record exists of the Framers having discussed martial law at the Constitutional Convention. Early Congresses passed several laws allowing the deployment of state militias and federal troops in emergencies—but only to help enforce the law, not displace it.

Martial law was first invoked in the young nation during the War of 1812 by General Andrew Jackson in New Orleans. Laws “must sometimes be silent,” he wrote, “when necessity speaks.” But despite Jackson’s heroic defense of the city against the British, his suspension of civilian government there—which continued even after the war officially ended—was widely criticized as unnecessary.

State or territorial officials also declared martial law several times in the early days of the Republic. When a full-fledged revolt broke out against the Rhode Island government in the Dorr Rebellion, in 1841, the Supreme Court in Luther v. Borden approved the imposition of martial law, saying that the Court would not question the state’s authority. One justice dissented vehemently, however, warning that under martial law “every citizen, instead of reposing under the shield of known and fixed laws as to his liberty, property, and life, exists with a rope round his neck, subject to be hung up by a military despot at the next lamp-post, under the sentence of some drum-head court-martial.”

During the Civil War, President Lincoln declared martial law with regard specifically to “rebels and insurgents” and certain other disloyal individuals. Although Lincoln limited the application of martial law (it did not apply to the general population), in 1866 the Supreme Court ruled, in a case called Ex parte Milligan, that his order to try such persons by military commission was illegal where civilian courts remained open and operating.

In its decision, the Court laid out criteria for invocation of martial law:

If, in foreign invasion or civil war, the courts are actually closed, and it is impossible to administer criminal justice according to law, then, on the theatre of active military operations, where war really prevails, there is a necessity to furnish a substitute for the civil authority, thus overthrown, to preserve the safety of the army and society; and as no power is left but the military, it is allowed to govern by martial rule until the laws can have their free course.

And, the Court said, “As necessity creates the rule, so it limits its duration.” The Court warned of allowing this extraordinary measure under other circumstances: “Civil liberty and this kind of martial law cannot endure together; the antagonism is irreconcilable; and, in the conflict, one or the other must perish.”

[Elizabeth Goitein: The alarming scope of the president’s emergency powers]

The Court apparently failed to consider the possibility that the courts might be closed by military order. In such a case, of course, no one would be left to judge the legitimacy of the military’s actions.

The objective criteria set out by the Court—the presence of war, actual insurrection or invasion, effective closure of courts, displacement of civil authorities, and no alternative to protect the Army and society—left plenty of room for judgment about when martial law could be proclaimed. Yet they revealed the kind of extreme conditions that might justify its use.

Martial law was declared a number of times in the late nineteenth and early twentieth centuries at the state level, by governors acting as commanders in chief of their militias or national guards. Most often the declarations resulted from labor disputes. In a 1903 miners’ strike, for example, Colorado Governor James Peabody declared martial law in San Miguel County, where Telluride is located. He closed the saloons, imposed a curfew, censored the press, collected guns, and suspended habeas corpus, although the civil courts remained open. He also ordered state troops to arrest and detain Charles Moyer, the president of the Western Federation of Miners. In the Supreme Court’s 1909 decision in Moyer v. Peabody, Justice Oliver Wendell Holmes upheld the legality of Peabody’s use of martial law, writing that “the governor’s declaration that a state of insurrection existed is conclusive of that fact … When it comes to a decision by the head of the state upon a matter involving its life, the ordinary rights of individuals must yield to what he deems the necessities of the moment.”

In 1932, however, the Court reversed course when Texas Governor Ross Sterling declared martial law in several counties. The governor claimed that he was acting to quell an insurrection, but his real purpose was to halt oil and gas production, in an effort to arrest falling prices caused by an oversupply of petroleum. He argued that “the court was powerless … to intervene,” and that his order had the quality of a “supreme and unchallengeable edict.” But in Sterling v. Constantin, a unanimous Court struck down the declaration, concluding that otherwise “the fiat of a state Governor, and not the Constitution of the United States, would be the supreme law of the land … Under our system of government, such a conclusion is obviously untenable.” How to challenge the legitimacy of a declaration? “What are the allowable limits of military discretion,” the Court wrote, “and whether or not they have been overstepped in a particular case, are judicial questions.” Still, the Court offered no new clues about when martial law might be justified.

Over the years, the Department of Defense has issued various statements and regulations that emphasize (as one 1960 Army lecture had it) the idea that civilian deference to military authority is “repulsive to the American concept of government.” A 1941 War Department field manual declared, channeling the Supreme Court’s decision in Ex Parte Milligan, that martial law could be invoked only when “the machinery of the civil government has broken down, and the courts are no longer properly and unobstructedly exercising their jurisdiction.” (And when it is invoked, “the civil and criminal laws continue in force, except insofar as their actual enforcement may be suspended for the time being by inability of the civil authorities to function, or in specific particulars, as a matter of military necessity, by order of the President or of the military commander acting by authority of the President.”) A more recent Defense Department regulation stated,

Martial law depends for its justification upon public necessity. Necessity gives rise to its creation; necessity justifies its exercise; and necessity limits its duration. The extent of the military force used and the actual measures taken, consequently, will depend upon the actual threat to order and public safety which exists at the time. In most instances the decision to impose martial law is made by the President … However, the decision to impose martial law may be made by the local commander on the spot, if the circumstances demand immediate action, and time and available communications facilities do not permit obtaining prior approval from higher authority.

But this regulation was inexplicably removed in 2008 and not replaced, so current military rules pertaining to martial law are not known.

In the absence of any further clarification from the courts, or from Congress, or even from the military itself, we cannot rule out the possibility that in an acute domestic crisis like the one we face now, the president or a military commander might, like Lincoln or Jackson, decide to take matters into their own hands. Any court test of these actions would almost certainly be retrospective, if it occurred at all. Even if courts continued operating during military rule, judges have always been reluctant to second-guess the military, especially during wartime.

[Read: This is how Donald Trump will be remembered]

But Trump’s “wartime president” rhetoric notwithstanding, invocation of martial law would be utterly unjustified and lawless. The coronavirus threatens the health of many citizens, and it may wreck the economy. But civilian government is adapting to the crisis. Courts remain open and operating, with modified procedures. And there has been no hint of insurrection, no widespread lawbreaking or domestic unrest. None of the conditions used to justify martial law in the past are present today or are likely to arise.

Not long ago a top civilian official in the Pentagon declared, “Our goal is not to declare martial law and take control. Our goal is to avoid that at all costs.” His statement reflects our understanding that martial law would threaten not only civil liberties but also democracy itself.