On September 20th, Senator Bernie Sanders released a statement on his website announcing that “a major bloc of 29 Democrat senators, led by Independent Senator Bernie Sanders, took a strong stand against any cuts to Social Security as part of a deficit reduction deal”:
“We will oppose including Social Security cuts for future or current beneficiaries in any deficit reduction package. [...] Even though Social Security operates in a fiscally responsible manner, some still advocate deep benefit cuts and seem convinced that Social Security hands out lavish welfare checks. But Social Security is not welfare. Seniors earned their benefits by working and paying into the system,” the senators said in a letter circulated by Sen. Bernie Sanders (I – VT), the founder of the Senate Defending Social Security Caucus.
Senate Majority Leader Harry Reid (D-NV) and Sen. Charles Schumer (D-NY), the Senate’s No. 3 leader, signed the letter. So did Sens. Mark Begich (D-AK), Sheldon Whitehouse (D-RI) and Al Franken (D-MN), who joined Sanders at a Capitol news conference. (source)