The legislation would increase Social Security benefits by about $1,300 annually for seniors who make less than $16,000, while boosting the amount of taxes paid by high-income earners by subjecting incomes above $250,000 to payroll taxes.
Sanders argued that his proposal has an "overwhelming majority" of support in both parties, pointing to an Oct. 2016 Public Policy Polling survey that found that 72 percent of Americans support increasing the entitlement program.
Rep. Peter DeFazio (D-Ore.) is introducing a House version of the bill.