department responsible for the procurement may waive this restriction on a case-by-case basis by certifying in writing to the Committees on Appropriations of the House of Representatives and the Senate that adequate domestic supplies are not available to meet Department of Defense requirements on a timely basis and that such an acquisition must be made in order to acquire capability for national security purposes: Provided further , That these restrictions shall not apply to contracts which are in being as of the date of the enactment of this Act. 8025. For the purposes of this Act, the term congressional defense committees means the Armed Services Committee of the House of Representatives, the Armed Services Committee of the Senate, the Subcommittee on Defense of the Committee on Appropriations of the Senate, and the Subcommittee on Defense of the Committee on Appropriations of the House of Representatives. 8026. During the current fiscal year, the Department of Defense may acquire the modification, depot maintenance and repair of aircraft, vehicles and vessels as well as the production of components and other Defense-related articles, through competition between Department of Defense depot maintenance activities and private firms: Provided , That the Senior Acquisition Executive of the military department or Defense Agency concerned, with power of delegation, shall certify that successful bids include comparable estimates of all direct and indirect costs for both public and private bids: Provided further , That Office of Management and Budget Circular A–76 shall not apply to competitions conducted under this section. 8027. (a) (1) If the Secretary of Defense, after consultation with the United States Trade Representative, determines that a foreign country which is party to an agreement described in paragraph (2) has violated the terms of the agreement by discriminating against certain types of products produced in the United States that are covered by the agreement, the Secretary of Defense shall rescind the