Article I, Section 9, Clause 7 of the United States Constitution states:
“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 is the “Power of the Purse” clause, which Article I, Section 7, Clause 1 makes clear is exclusively held by the House of Representatives:
“All Bills for raising Revenue shall originate in the House of Representatives; but the Senate may propose or concur with Amendments as on other Bills.”
Actually, there are two “powers of the purse” – to spend money or to deny its being spent. For the US Federal Government to spend any money, one single dime on anything, three things need to happen in this order: 1) an Appropriation must be authorized and passed by the House, 2) such Appropriation must then be passed by the Senate (any differences in the House and Senate versions must be reconciled via joint agreement and passage), and finally 3) be signed into Law by the President.