50 USC § 1811. Authorization during time of war
Notwithstanding any other law, the President, through the Attorney General, may authorize electronic surveillance without a court order under this subchapter to acquire foreign intelligence information for a period not to exceed fifteen calendar days following a declaration of war by the Congress.
(Pub. L. 95–511, title I, §111, Oct. 25, 1978, 92 Stat. 1796.)