R.I. Gen. Laws § 30-2-5: Declaration of martial law.

In case of war, invasion, rebellion, insurrection, riot, tumult, public calamity or catastrophe, or other emergency, or imminent danger thereof, or resistance to the laws of this state, or the United States, the governor may, if in his or her judgment the maintenance of law and order and the protection of person and property will thereby be promoted, by proclamation, declare the state, or any part thereof, to be under martial law.