Vice President Joe Biden appeared to endorse same-sex marriage on Meet the Press yesterday, though he did so in his usual Bideneseque way: proclaiming himself “absolutely comfortable with the fact that men marrying men, women marrying women, and heterosexual  men and women marrying another are entitled to the same exact rights all the civil rights, all the civil liberties. And quite frankly, I don’t see much of a distinction — beyond that.”

Quite a word omelet compared to “I support same-sex marriage.”

Both Biden and the Obama campaign quickly walked back the comments, making reference to their “evolving” positions on the issue. Some think it was a typical unscripted Biden flub; others suspect he is looking ahead to 2016, when he could need to face a Democratic base that supports gay marriage by a wide margin. Obama is reportedly facing pressure from gay donors. His two best voting blocs are split on the issue: young voters (who support gay marriage) and blacks (who oppose it). The damage a same-sex marriage would do to Obama among black voters would almost certainly be minimal, but in a close election even that may be too much to afford.

But do Obama and Biden really oppose same-sex marriage in any meaningful sense? They oppose the Defense of Marriage Act, they oppose any other federal legislation or amendment on the issue, they did not support Proposition 8 or any comparable state ballot initiative. Their opposition seems limited to being able to say, “I believe marriage is between a man and a woman” in debates. But their party’s evolution seems complete.

Obama will probably be the last Democratic presidential nominee to even nominally oppose same-sex marriage. The only question is whether that will be Obama ’08 or Obama ’12.