There’s a ton of speculation out there to the effect that in an interview with ABC News this afternoon, Obama will finally complete his evolution on gay marriage, after days of intense pressure to clarify where he stands, in the wake of Joe Biden’s vague but supportive comments over the weekend.

An ABC News source says the question will be asked in the interview today, and gay rights advocates are fully expecting him to finally state clearly that he supports full equality for gay and lesbian Americans, and perhaps even that it’s time the country accepts the inevitable.

“My guess is that he’s decided to share with the country the process he’s been through, and where he’s ended up,” Richard Socarides, the prominent gay rights advocate, tells me. “Hopefully it will contribute to the national conversation and lead to a consensus on it.”

“I’m sure it’s clear to them now that he can’t remain neutral about this, especially in the context of a presidential election,” Socarides continued.

White House press secretary Jay Carney has hinted in recent days that Obama has more to say on the topic. “I’m sure it is the case that he will be asked again at some point when he gives interviews or press conferences about this issue, and I’ll leave it to him to describe his personal views,” Carney said yesterday.

Adding to the mystery, Carney abruptly canceled today’s White House press briefing, which generally happens when big news is about to be made. Obama’s advisers have gone quiet this morning on the issue; at least three I contacted refused any comment.

Obama has the best gay rights record of any president. Fair or not, that has left him less maneuvering room than he might have hoped for when it comes to embracing marriage equality itself. His record has only served to convince everyone that he does favor full equality for gay and lesbian Americans — but won’t say so for political reasons.

Whatever Obama is going to say, the heightened expecations themselves underscore yet again that his current position has been untenable ever since he proclaimed that his views on the topic are evolving. It’s hard to imagine that we won’t gain a good deal more clarity from Obama today. The alternative would be worse for him, and worse for the country.