2 U.S.C. § 621: Congressional declaration of purpose

The Congress declares that it is essential—(1) to assure effective congressional control over the budgetary process; (2) to provide for the congressional determination each year of the appropriate level of Federal revenues and expenditures; (3) to provide a system of impoundment control; (4) to establish national budget priorities; and (5) to provide for the furnishing of information by the executive branch in a manner that will assist the Congress in discharging its duties.