Richard Socarides is optimistic:
[T]he remarkable new reality for Obama in this election is that supporting marriage equality is smart politics. A majority of independents and young voters already favor equal marriage rights. These are important voting blocks, and a key part of the President’s reëlection strategy. Support for gay rights will also help him energize liberals in the Party and others who think he has not acted boldly around core progressive issues such as immigration and the environment and on other civil-rights issues. Hard-right conservatives who strongly oppose marriage rights, meanwhile, will never support Obama anyway.
It won't happen.