I agree that having a lesbian daughter has changed Dick Cheney's perspective, without that, Dick Cheney would probably be one of the biggest gay bashers on the planet.
As for Obama, he has so much on his plate now, that trying to push gay MARRIAGE now would be extremely politically divisive at exactly the wrong time.
As it is, we must face the facts, the best hope for gay marriage will be through the courts, and SCOTUS is where the argument will finally be won. Already many Judges are saying weasel words like gay unions are too much like separate but equal doctrines that fail the sniff test, and if we are going to a allow a full marriage for heterosexuals, then nothing but a full gay marriage will meet the full equality sniff test.
And as Obama tries to get his first SCOTUS pick through, its unlikely to change the balance of SCOTUS much, but if Obama gets to pick a replacement for any in what amounts to the gang of 4 in Roberts, Alito, Scalia, or Thomas, virtually any SCOTUS pick will send the balance of the court decidedly leftward. And then, with the right court case, SCOTUS, at one stroke, could legalize gay marriage nationwide. The religious right can howl to their hearts content, but like the end to slavery, and the female right to vote, there is something simply fair about a full gay marriage that makes it inevitable