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.