Martial law in the United States
Martial law in the United States refers to times in United States history in which 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.
Source: Wikipedia — Martial law in the United States (CC BY-SA 4.0)