Though it's not well defined in U.S. law, martial law could be declared in the U.S., and has been imposed relatively rarely in the country's history during times of war, unrest and natural disaster.

South Korea’s Constitution places strict limits on how a president can declare martial law: It must be during war or comparable national emergency; the president must hold a deliberation at a ...

A South Korean court has approved the arrest of former President Yoon Suk Yeol on charges related to his brief imposition of martial law in December, accepting a special prosecutor’s claim that he poses a risk of destroying evidence.