What Is Martial Law?

What is martial law?

Martial law is when the military takes over civilian government. Civilian courts close. Military tribunals replace them. The military issues orders directly to civilians.

Civil liberties, including habeas corpus, free speech, and assembly, can be restricted or suspended.

There is no explicit constitutional provision granting the power to declare martial law. The Supreme Court has never directly held that the federal government has this power. It has happened 68 times anyway.

What Powers Martial Law Unlocks

Every Time Martial Law Was Declared

The 68 declarations break down by cause. The pattern is revealing: the largest category is labor disputes, not wars or natural disasters.

Martial Law Declarations by Cause

Category	Value
Labor disputes	22
Racial violence	6
Wartime / rebellion	11
Political disputes	12
Natural disasters	5
Other	12

Source: Brennan Center Guide to Declarations of Martial Law. Labor disputes are the #1 cause.

Key examples

1814, New Orleans: Andrew Jackson declared martial law during the War of 1812. Arrested a federal judge who tried to issue a habeas writ.

1921, Tulsa: Declared after the Tulsa Race Massacre. The National Guard detained Black residents, not the white mobs who destroyed 35 blocks.

1941, Hawaii: After Pearl Harbor. Military tribunals replaced civilian courts. Lasted until October 1944. The last federal martial law declaration.

1963, Cambridge, MD: The last state-level declaration. Civil rights protests. National Guard deployed for over a year.

The Insurrection Act: the more immediate threat

Martial law displaces civilian government. The Insurrection Act keeps civilian government in place but deploys the military as domestic police. The distinction matters because the Insurrection Act is far easier to invoke.

Troops Deployed, Courts Pushed Back, the Act Was Never Invoked

The Insurrection Act has not been formally invoked in 2025 or 2026. But the administration threatened it, deployed federalized National Guard troops over governors’ objections, and lost in court.

Minneapolis, January 15, 2026. Trump posted on Truth Social that he would “enact the INSURRECTION ACT” if Minnesota officials did not stop protests around ICE operations. Homeland Security Secretary Kristi Noem told NBC News she had discussed the option with the president that day. No formal proclamation followed.

Los Angeles, 2025. The administration federalized California National Guard troops and deployed them for arrests, searches, traffic and crowd control, and interrogation. In August 2025, a federal judge ruled the deployment violated the Posse Comitatus Act, the 1878 law that bars the military from acting as domestic police. In December 2025, a second ruling ordered control of California Guard soldiers returned to the governor.

Chicago, October 2025. Trump federalized 300 Illinois National Guardsmen over Governor Pritzker’s objections and deployed 200 members of the Texas National Guard. A lower court blocked the deployment. The Supreme Court kept the troops out pending litigation. The 7th Circuit wrote: “political opposition is not rebellion.”

The legal authority cited was not the Insurrection Act. The administration used Title 10 federalization of state Guard units. Courts held this did not authorize domestic law enforcement. The Insurrection Act remains unused since 1992, but the line between threat and invocation narrowed in 2025-2026.

How Other Countries Limit Martial Law

South Korea’s 3-hour martial law showed what a functioning democracy does: the legislature voted to overturn it immediately and the president was prosecuted. The Philippine example showed what happens when no one stops it.

Bills to Limit Martial Law Powers

H.R. 4076, introduced by Rep. Chris Deluzio, and companion legislation from Sen. John Hickenlooper: the Insurrection Act of 2025. Would narrow deployment criteria, require congressional consultation, impose a 7-day limit without congressional approval, clarify the Act cannot be used to suspend habeas corpus or impose martial law, and provide for judicial review.

What you can do

1. Support Insurrection Act reform. Contact your senators about S.2070.
2. Reform the National Emergencies Act
3. Read the 48 active national emergencies brief and the Rule of Law hub.