Luther v. Borden

Martial law is implemented when constitutional law is suspended, and civil authority is replaced by military government. Usually this occurs in times of natural disaster, war, or other forms of unrest. During the twentieth century, nationwide martial law has been declared, and sustained for long periods of time, in countries ranging from the Philippines to Poland.

Martial law has been imposed in the United States during the enforcement of civil rights or during urban rioting. One of the most notable uses of martial law occurred in Little Rock, Arkansas, in 1957, when President Eisenhower sent in federal troops to enforce integration of public schools. The California National Guard was activated in 1992 to deal with rioting in Los Angeles following the handing down of a "not guilty" verdict for four white police officers charged with beating black motorist Rodney King. Martial law was also proclaimed twice during the Civil War, when President Abraham Lincoln suspended the writ of habeas corpus, and in Hawaii following the bombing of Pearl Harbor by the Japanese on 7 December 1941.