(a) In the event of a declaration of war or the declaration by the President of a national emergency in accordance with the National Emergencies Act ( 50 U.S.C. 1601 et seq.) that requires use of the armed forces, the Secretary of Defense , without regard to any other provision of law, may undertake military construction projects, and may authorize the Secretaries of the military departments to undertake military construction projects, not otherwise authorized by law that are necessary to support such use of the armed forces. Such projects may be undertaken only within the total amount of funds that have been appropriated for military construction, including funds appropriated for family housing, that have not been obligated. (b) When a decision is made to undertake military construction projects authorized by this section, the Secretary of Defense shall notify, in an electronic medium pursuant to section 480 of this title , the appropriate committees of Congress of the decision and of the estimated cost of the construction projects, including the cost of any real estate action pertaining to those construction projects. (c) The authority described in subsection (a) shall terminate with respect to any war or national emergency at the end of the war or national emergency. (Added Pub. L. 97–214, § 2(a) , , 96 Stat. 157 ; amended Pub. L. 115–91, div. B, title XXVIII, § 2801(a)(6) , , 131 Stat. 1841 .)