Martial law is the temporary substitution of military authority for civilian government in an emergency. In the United States, government officials have invoked martial law during war, labor disputes, natural disasters, and in times of civil unrest.
The defining feature of martial law is the displacement of the civilian government by the military. When martial law is in effect, military commanders, not elected officials, make laws; soldiers, not local police, enforce laws; and ordinary citizens accused of defying martial law might face military tribunals instead of civilian courts.
Civilian governments rarely invoke martial law. Since the United States was founded in 1776, government officials have declared martial law roughly 68 times. Federal and state authorities are much more likely to request "domestic military assistance," which is not the same as martial law. Domestic military assistance supports, rather than supplants, civilian government. For example, in the aftermath of Hurricane Katrina in 2005, federal troops used military helicopters to conduct search and rescue missions that local governments were unable to do themselves. In 1992, President George H.W. Bush deployed the National Guard to help state and local law enforcement suppress riots in Los Angeles.
Historically, state governors are most likely to declare martial law in cities and counties in their jurisdictions. The federal government's authority to invoke martial law is less settled and has been used sparingly.
The United States Constitution doesn't explicitly mention martial law. No federal statute or U.S. Supreme Court decision clearly states who has the authority to declare martial law and under what circumstances.
Constitutional law scholars who study executive power and the origin of martial law note that the President is the commander in chief of the military. (U.S. Const., art. II, § 2.) But Congress regulates when and where the military can be used for activities, like civilian law enforcement, typically associated with martial law. (18 U.S.C. § 1385 (2020).)
While lacking authority to unilaterally declare martial law, under the Insurrection Act the President has limited authority to deploy troops to suppress a domestic rebellion and enforce federal law. (10 U.S.C. §§ 251 to 253 (2020).) But federal troops deployed pursuant to the Insurrection Act are a supplement to civilian government, not a replacement. President John F. Kennedy invoked the Insurrection Act in 1962 and 1963 to send federal troops to Mississippi and Alabama to enforce civil rights laws.
The U.S. Supreme Court has explicitly held that individual states have the power to declare martial law within their borders. Typically, a governor's power to declare martial law originates in the state's constitution.
But even under martial law, state officials must comply with the U.S. Constitution and federal laws. Federal courts generally won't second-guess whether a state governor's declaration of martial law is necessary, but they will review whether state actions taken under martial law are constitutional.
Under martial law, military leaders assume executive, legislative, and judicial powers. When martial law is in effect, military leaders might:
Civilians who commit crimes or violate military orders face military tribunals if civilian courts are unavailable. For more information about what life is like for civilians under military law, check out: After Pearl Harbor, Hawaii Spent Three Years Under Martial Law.
Government officials can invoke martial law under limited circumstances, but checks and balances remain. Contact a lawyer if you have questions about your rights under martial law.
If you are facing criminal charges, you should speak with a criminal defense attorney. If you want to know whether you have a viable claim against the government for a violation of your rights, consider consulting a civil rights attorney.