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.