No role of Congress is more central than passing a budget: it's the first subject mentioned under powers of the Congress. From Article 1, section 8.
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
Lately, the Congress has proved singularly inept at this central task. I suggest a modification of the Constitution to provide that if Congress has so failed, by the end of the fourth week of the fiscal year, all members be summarily removed and made ineligible to hold any office of trust under the United States for four years.