The Constitution is built on an Anglo-American tradition of checks and balances. It separates control of the sword from control of the purse. To check the chief executive, who holds the sword, the framers vested in an elected legislature the “power of the purse.” Congress controls spending not merely to ensure popular consent to taxation, but also to protect liberty. As James Madison wrote in Federalist No. 58, the purse is “the most complete and effectual weapon” the people’s representatives possess to secure “a redress of every grievance” and to enact “every just and salutary measure.”