Article 1, Section 9, Clause 7: Appropriations Clause

No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law; and a regular Statement and Account of the Receipts and Expenditures of all public Money shall be published from time to time.

This clause establishes that under no circumstances can an officer of the federal government disburse funds that have not been appropriated for that purpose by Congress.

This has never been held to prohibit appropriation of large lump sums for very broad purposes, with the executive given considerable latitude on precisely how the sums are spent. Most of the modern wars of the United States have been funded by such large and general appropriations. Congress was even permitted in 1902, to declare that all funds received for the sale of certain public lands were to be used at the discretion of the Secretary of the Interior for land reclamation. The relevant act was regarded by the courts as a valid appropriation, even though the amount of the appropriation was not specified nor the precise manner in which the appropriation was to be spent, other than a general directive that it be spent on land reclamation.

The prohibition on any disbursement of funds without an authorizing appropriation is absolute enough that persons who had supported the Confederacy during the Civil War, and were subsequently pardoned, still had to appeal to Congress to appropriate funds to reimburse them for property seized and sold by the government during the war. Failure by Congress to appropriate funds to pay a legal or moral debt prevents any payment of such debt, though it does not remove the legal or moral obligation to eventually do so.