Foreign Military Sales (FMS) is the primary mechanism through which the U.S. government sells defense equipment and services to allied nations. Under the FMS program, the U.S. Department of Defense acts as the official seller — purchasing the equipment from American defense contractors and reselling it to the foreign government at cost plus administrative fees. FMS sales require State Department approval under the Arms Export Control Act, and Congress can block them through joint resolutions of disapproval. The program generates revenue for American defense contractors, builds military interoperability with allies, and allows the State Department to condition sales on human rights compliance.