375.2—National emergency and effective date.
A period of national emergency shall be deemed to exist and the provisions of this part shall become effective only (a) after an attack upon the United States, or at a time specified by the authority of the President after such attack, and (b) by order of the Chair of the Board or his or her successor as set forth in § 375.5, or when it is no longer possible to communicate with such official at his or her designated station.