by certifying in writing to the Committees on Appropriations of the House of Representatives and the Senate that it is in the national security interest to do so. 8061. (a) The Secretary of Defense may, on a case-by-case basis, waive with respect to a foreign country each limitation on the procurement of defense items from foreign sources provided in law if the Secretary determines that the application of the limitation with respect to that country would invalidate cooperative programs entered into between the Department of Defense and the foreign country, or would invalidate reciprocal trade agreements for the procurement of defense items entered into under section 2531 of title 10, United States Code, and the country does not discriminate against the same or similar defense items produced in the United States for that country. (b) Subsection (a) applies with respect to— (1) contracts and subcontracts entered into on or after the date of the enactment of this Act