And now...Alaska

[Yelnoc]

Considering the lay of the land, same sex marriage is likely to be legal in every state before Obama leaves office. He's had very little to do with that, yet I suspect future historians will the legalization of same sex marriage one of his major achievements.

[Holmes]

You're wilfully ignorant if you think Obama has nothing to do with this. From declaring his support on national television (and Biden had done this earlier) probably helped push some people vote in favor of it in Washington, Maine and Maryland back in 2012, and those victories helped start moving the ball. And then the DOJ's decision not to defend DOMA was also significant.

[eric82oslo]

Considering the lay of the land, same sex marriage is likely to be legal in every state before Obama leaves office. He's had very little to do with that, yet I suspect future historians will the legalization of same sex marriage one of his major achievements.

I'd say Biden and Obama both had quite a bit to do with it.
They were the first vice president and president to publically endorse it after all, and they both did it emphatically and with great passion. I'm sure that tipped the scale for many people's perception of the issue.