As Noah noted below, the DNC’s platform-drafting committee today voted to include support for same-sex marriage in the party platform. The NRSC noted in an e-mail to reporters this afternoon that not all Democrats are going to be thrilled about this switch: “Sen. Jon Tester in Montana, Sen. Claire McCaskill in Missouri and former Gov. Tim Kaine in Virginia have declined to support same-sex marriage, even as Mr. Obama’s backing has galvanized the party’s liberal wing and activist ranks. Even senators facing less-competitive races — Bob Casey of Pennsylvania, Joe Manchin of West Virginia and Bill Nelson of Florida — have sought distance from Mr. Obama on same-sex marriage.”
What will be interesting is whether this widespread adoption of supporting legalization of same-sex marriage causes any Democratic voters to reconsider their support. In California, for instance, the Associated Press’s exit polls found that 70 percent of black voters and over 50 percent of Latino voters — both groups that skew heavily Democratic — voted for Proposition 8 in 2008.