Next, Congress passes thirteen annual appropriations bill which must be signed into law by the President. These appropriations bill provide the spending levels for federal programs and represent the final budget. A. Discretionary spending is spending authorized by the Congress and the President in the 13 annual appropriations bills. Spending on individual discretionary programs may vary year to year based upon the level of spending authorized by Congress. Total discretionary spending represents one-third of all federal spending.
Mandatory spending is authorized by permanent laws.
Programs such as Social Security and Medicare are mandatory spending. Spending levels for these programs are determined by the amount necessary to comply with the law and not by the annual appropriations bills. Mandatory spending accounts for two-thirds of total federal spending.