Today is obviously a great and historic moment for President Obama, who decided today to follow the Prospect's Jamelle Bouie's advice and openly favor same-sex marriage. The effects are primarily symbolic, but it's still a good thing that he decided to match his excellent policy record on LBGT issues with the correct position on a crucial civil-rights issue.
One question that is sure to come up is whether this decision will harm President Obama's chance of re-election. I'm sure some members of Obama's political team were urging him to maintain the incoherent mess of a position he nominally took before today. This is, for reasons I discussed in the context of LBJ last week, certainly a serious question. Romney winning the 2012 election would be a disaster for LBGT rights, starting with the fact that this would probably result in Antonin Scalia being to the left of the median Supreme Court justice. Particularly since Obama has done pretty much all that is within his power to advance marriage equality in policy terms, if supporting same-sex marriage would make a Romney victory more likely, his unwillingness to openly support same-sex marriage is defensible (like LBJ's nominal pre-1957 opposition to civil rights).
But I don't think there's any reason to believe that Obama doing the right thing today will help Romney in November. It's important to remember that Obama and Romney were substantially different on gay and lesbian rights before this afternoon. To believe that Romney will benefit significantly from Obama's embrace of same-sex marriage rights, you would have to believe that there's a group of voters who 1) care enough about same-sex marriage to make it their top priority in a federal election, but 2) are willing to ignore Obama's pro-LBGT rights record as long as he doesn't nominally support same-sex marriage. The number of people who fit into this class is too trivial to be worth worrying about. It's likely that some-risk adverse advisers cited the argument that same-sex marriage cost John Kerry the election in 2004. But there's no evidence that this is true. Given that same-sex marriage is significantly more popular now than it was eight years ago, it's even more unlikely that same-sex marriage would damage Obama now.
Obama embracing same-sex marriage was the right thing to do, and there's no reason to believe that it will be politically damaging. Presidential elections generally don't turn on social issues and it's hard to imagine that 2012 will be an exception (even if we assume that Obama's position is a net negative, which is possible but hardly self-evident).
