Martial law in the United States refers to times in United States history in which in a region, state, city, or the whole United States was placed under the control of a military body. On a national level, both the US President and the US Congress have the power, within certain constraints, to impose martial law since both can be in charge of the militia. In each state, the governor has the power to impose martial law within the borders of the state.[1] In the United States, martial law has been used in a limited number of circumstances, such as New Orleans during the Battle of New Orleans; after major disasters, such as the Great Chicago Fire of 1871, the 1906 San Francisco earthquake, or during riots, such as the Omaha race riot of 1919 or the 1920 Lexington riots; local leaders declared martial law to protect themselves from mob violence, such as Nauvoo, Illinois, during the Illinois Mormon War, or Utah during the Utah War; or in response to chaos associated with protests and rioting, such as the 1934 West Coast waterfront strike, in Hawaii after the Japanese attack on Pearl Harbor, and during the Civil Rights Movement in response to the Cambridge riot of 1963.
The martial law concept in the United States is closely tied to the right of habeas corpus, which is, in essence, the right to a hearing and trial on lawful imprisonment, or more broadly, the supervision of law enforcement by the judiciary. The ability to suspend habeas corpus is related to the imposition of martial law.[2] Article 1, Section 9 of the US Constitution states, "The Privilege of the Writ of Habeas Corpus shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it." There have been many instances of the use of the military within the borders of the United States, such as during the Whiskey Rebellion and in the South during the Civil Rights Movement, but those acts are not tantamount to a declaration of martial law. Deployment of troops does not necessarily mean that the civil courts cannot function, which is one of the keys,[vague] as the US Supreme Court noted,[citation needed] to martial law.
In United States law, martial law is limited by several court decisions that were handed down between the American Civil War and World War II. In 1878, Congress passed the Posse Comitatus Act, which forbids US military involvement in domestic law enforcement without congressional approval.
Throughout history, martial law has been imposed at least 68[3] times in limited, usually local areas of the United States. Martial law was declared for these reasons: Twice for war or invasion, seven times for domestic war or insurrection, eleven times for riot or civil unrest, 29 times for labor dispute, four times for natural disaster and fifteen times for other reasons.[3] Habeas corpus was suspended federally only once in 1863 during the Civil War.