What Is Martial Law?

Martial law is the substitution of a civil government by military authorities with unlimited powers to suspend the ordinary legal protections of civilian rights. A state of martial law may be declared in response to a crisis or imposed during a coup.

In times of disaster or civil unrest, a declaration of emergency is more common than a declaration of martial law because it is easier to reverse. An emergency declaration allows the government to expand its powers temporarily to deal with a crisis, suspending some civil liberties but avoiding military control.

Understanding Martial Law

The declaration of martial law is a rare and momentous decision for a civilian government to make and for good reason. When martial law is declared, civilian control of some or all aspects of government operations is ceded to the military. This means that, in the case of elected governments, the representatives chosen by the voting population are no longer in power. Civilians have ceded control of the country in exchange for the potential restoration of order, with the possibility that control may not be reclaimed in the future.

When martial law is declared, civil liberties—such as the right to free movement, free speech, or protection from unreasonable searches—can be suspended. The justice system that typically handles issues of criminal and civil law is replaced with a military justice system, such as a military tribunal.

Civilians may be arrested for violating curfews or for offenses that, in normal times, would not be considered serious enough to warrant detention. Laws relating to habeas corpus that are designed to prevent unlawful detention may also be suspended, allowing the military to detain individuals indefinitely without the possibility of recourse.

Declaring Martial Law

Considering the negative ramifications martial law can have on a country and its citizens, declaring martial law is a last resort reserved for situations where law and order are rapidly deteriorating. For example, in 1892, the governor of Idaho instituted martial law after a group of rebellious mine workers blew up a mill, which leveled a four-story building and killed several people.

Martial law may be declared to reign in protests, civil unrest, coup d’états, or insurrections. It may also be declared when a country’s military occupies foreign territory, such as at the end of a war. Typically, the power to declare martial law rests with a nation's president or other top civilian leader. The circumstances in which it may be declared and other limiting factors, such as the amount of time it may be left in effect, are governed by legislation or a country’s constitution. For example, a president may be authorized to declare martial law during a time of violent civil unrest, but only for 60 days. International laws may also limit the scope and duration of martial law if a country has signed onto a multilateral treaty.

Special Considerations: States of Emergency vs. Martial Law

The use of martial law in the wake of natural disasters is less common than during situations of civil unrest or disorder. Rather than declaring martial law and handing over power to the military in the case of a hurricane or earthquake, governments are much more likely to declare a state of emergency.

When a state of emergency is declared, the government may expand its powers or limit the rights of its citizens. The government does not, however, have to hand power over to its military. In some cases, a government may invoke a state of emergency specifically to suppress dissent or opposition groups.