Sen. Tim Johnson, a Democrat from South Dakota, is the latest senator to say that he supports same-sex marriage, leaving just three Democrats left standing who have not.
"After lengthy consideration, my views have evolved sufficiently to support marriage equality legislation," he said in a statement. "This position doesn't require any religious denomination to alter any of its tenets; it simply forbids government from discrimination regarding who can marry whom."
Johnson also recently announced that he will not run for reelection in 2014.
Joe Donnelly, Ind., and Heidi Heitkamp, N.D., announced their support last week, leaving just Joe Manchin W. Va., Mark Pryor, Ark., and Mary Landrieu, La., as the only Senate Dems who have not.