Present Obama, while running for the Senate in Illinois, endorsed same-sex marriage unequivocally in 1996. Then, in August of 2008, running for President, then Senator Obama had apparently had a change of heart, because he defined marriage as "between a man and a woman."
I realize that as a politician seeking re-election President Obama thinks he must appeal to voters so they'll vote for him, but at this point, I think President Obama is in the "say what they want to hear" camp, and talking out of both sides of his mouth. He's perfectly willing to make mollifying statements to queers at fund raisers regarding "committed" same-sex relationships, but he's not rushing to encourage the repeal of DOMA, or changing his 2008 statement.
I don't think anyone, including President Obama actually has a clue regarding what he believes. I'm disillusioned enough by his rhetorical shifts and policy weaseling that I'm braced to hear the words "separate but equal" come out of his mouth.

