An appropriations act passed by Congress over the President's veto directs that one billion dollars "shall be spent" by the federal government for the development of a new military weapons system, which is available only from the Arms Corporation. On the order of the President, the Secretary of Defense refuses to authorize a contract for purchase of the weapons system. The Arms Corporation sues the Secretary of Defense alleging an unlawful withholding of these federal funds. The strongest constitutional argument for the Arms Corporation is that
passage of an appropriation over a veto makes the spending mandatory. Congress's power to appropriate funds includes the power to require that the funds be spent as directed. the President's independent constitutional powers do not specifically refer to spending. the President's power to withhold such funds is limited to cases where foreign affairs are directly involved