Congress wields the "power of the purse," creating a federal budget plan for government spending and revenue. This process involves both executive and legislative branches, with the President submitting a proposal and Congress determining the final budget through various committees and procedures. The budget process operates on a fiscal year basis and includes mandatory and discretionary spending. Key players like the Congressional Budget Office provide analysis, while Budget Committees draft resolutions and Appropriations Committees allocate funds to specific programs and agencies.