22 U.S.C. § 6446: Effects on existing contracts

under existing contracts or subcontracts, including the exercise of options for production quantities, to satisfy requirements essential to the national security of the United States; if the President determines in writing and so reports to Congress that the person or other entity to which the Presidential action would otherwise be applied is a sole source supplier of the defense articles or services, that the defense articles or services are essential, and that alternative sources are not readily or reasonably available; or if the President determines in writing and so reports to Congress that such articles or services are essential to the national security under defense coproduction agreements; or to products or services provided under contracts entered into before the date on which the President publishes his intention to take the Presidential action.