martial law, temporary government and control by military authorities of a territory or state, when war or overwhelming public disturbance makes the civil authorities of the region unable to enforce its law. Martial law refers to rule by the domestic army only; the rule of occupied territory by an invading army is known as military government. During a war, a nation may invoke martial law in some or all of its territory as part of the war effort. Martial law is also applied in serious cases of internal dissension; the army authorities may take over the administrative and judicial functions, and civil safeguards (e.g., habeas corpus and freedom of speech) may also be suspended. Where the civil courts remain open, even if their orders are executed by the military, martial law is not applicable. In the United States the federal government is limited in applying martial law by the provision of Article 1, Section 9, Subsection 2, of the Constitution, which concerns the suspension of habeas corpus. In most U.S. states, martial law may be proclaimed when deemed necessary for the public's safety. However, the U.S. Supreme Court in ex parte Milligan (1866) ruled that military trial of civilians when the civil courts were functioning was unconstitutional. Martial law, which applies to all persons, civil and military, in the area is to be distinguished from military law, the system of rules of government applying only to those in military service.