Martial law is a law administered by the military rather than a civilian government. Martial law may be declared in an emergency or response to a crisis, or to control occupied territory.

Breaking Down Martial Law

The declaration of martial law is a rare and momentous decision for a civilian government to make and for a 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 thus ceded control of the country in exchange for the potential restoration of order, with the possibility that control may not be given back in the future.

When martial law is declared, civil liberties, such as the right to free movement, to free speech or protection from unreasonable searches, can be suspended. The justice system that typically handles issues of criminal and civil law may be 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, designed to prevent unlawful detention, may also be suspended, allowing the military to keep individuals detained indefinitely without the possibility of recourse.

When to Declare Martial Law

Considering the negative ramifications, martial law can have on a country and its citizens, declaring martial law is reserved for situations in which law and order is rapidly deteriorating. It may be declared at home 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. 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 one person. The National Guard is sent to Coeur d'Alene to restore the peace, which resulted in over 600 people being arrested and two dozen tried in civil court.

Typically, the power to declare martial law rests with the president. 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 enshrined in 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.

The use of martial law in the wake of natural disasters is less common. Rather than declare martial law and hand 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.