22 U.S.C. § 441 — Proclamation of state of war between foreign states

(a) Issuance of proclamation. This section applies whenever the President, or Congress acting by concurrent resolution, finds that a state of war exists between foreign countries, and finds that proclaiming it is necessary either to promote the security or preserve the peace of the United States, or to protect the lives of United States citizens. When those conditions are met, the President must issue a proclamation naming the countries involved in that war. As more countries become involved in the war over time, the President must issue further proclamations, from time to time, naming those additional countries as well. (b) Revocation of proclamation. Once the state of war that caused the President to issue a proclamation under this section has ended, with respect to any country named in that proclamation, the President must revoke the proclamation as it applies to that country.