50 U.S. Code § 1701 - Unusual and extraordinary threat; declaration of national emergency; exercise of Presidential authorities
(a) Any authority granted to the President by section 1702 of this title may be exercised to deal with any unusual and extraordinary threat, which has its source in whole or substantial part outside the United States, to the national security, foreign policy, or economy of the United States, if the President declares a national emergency with respect to such threat.
(b) The authorities granted to the President by section 1702 of this title may only be exercised to deal with an …