Social Security, established in 1935, is the federal government’s largest program. It represents approximately one-fifth of the federal budget and provides retirement, disability and survivors' benefits to over 50 million Americans. Retirement benefits are distributed in amounts based on lifetime earnings.

The system is funded by a payroll tax of 12.4 percent up to a maximum amount of income ($106,800 in 2010). Half of the tax is paid by employers and half by employees. Nearly all wage-earners in the country pay Social Security taxes, with most of them paying more in Social Security taxes than they do in federal income taxes.