that expressly authorizes such strike. (b) First-Use nuclear strike defined In this section, the term first-use nuclear strike means an attack using nuclear weapons against an enemy that is conducted without the Secretary of Defense and the Chairman of the Joint Chiefs of Staff first confirming to the President that there has been a nuclear strike against the United States, its territories, or its allies (as specified in section 3(b)(2) of the Arms Export Control Act ( 22 U.S.C. 2753(b)(2) )).