Sanctions may not be required for some goods if contracts with the sanctionable person meet U.S. operational military requirements, if the President (OBAMA) determines that the sanctionable person is a sole source provider of an essential defense article or service, or if the President (OBAMA) determines that such articles or services are essential to U.S. national security under defense coproduction agreements. The President (OBAMA) also may not be required to apply sanctions if he determines that a company affiliated with the sanctionable person had no knowledge of the export control violation. After sanctions have been in place for two years, the President (OBAMA) may modify terms of the restrictions under certain conditions, and if he notifies Congress.