"Mandatory spending encompasses federal government spending on entitlement programs and food stamps as well as other budget outlays controlled by laws other than appropriation acts. Entitlement programs constitute the bulk of mandatory spending. More specifically, mandatory spending programs include Social Security, Medicare, temporary assistance to needy families (TANF), supplemental security income (SSI), unemployment insurance, veterans benefits, federal employee retirement and disability, food stamps, and the earned income tax credit. In all, federal spending accounts for about a fifth of gross domestic product (GDP), and mandatory spending accounts for over half of total federal spending. […] With discretionary spending as a percentage of GDP reduced to historic lows, any significant reductions in federal spending may well need to come from mandatory spending. Since Social Security, Medicare, and Medicaid account for most of the long-term increases in federal spending, these programs are likely to be considered for possible reductions. Focusing budget cuts on these three key programs, however, could compromise their goals: the economic security of the elderly and the poor. Fundamental reform may be proposed to eliminate the long-term fiscal strains while preserving the goals of these programs. This report will be updated annually."
CRS Report for Congress, RL33074