Whenever the President, or the Congress by concurrent resolution, shall find that there exists a state of war between foreign states, and that it is necessary to promote the security or preserve the peace of the United States or to protect the lives of citizens of the United States, the President shall issue a proclamation naming the states involved; and he shall, from time to time, by proclamation, name other states as and when they may become involved in the war.
Whenever the state of war which shall have caused the President to issue any proclamation under the authority of this section shall have ceased to exist with respect to any state named in such proclamation, he shall revoke such proclamation with respect to such state.
(Nov. 4, 1939, ch. 2, § 1, 54 Stat. 4.)