Vice President Joe Biden suggested Friday that it's just a matter of time before same-sex marriage is legal in all US states.

"I think the country is evolving," Biden told ABC's George Stephanopoulos. "I think there's an inevitability for a national consensus on gay marriage."

Same-sex marriage is one issue where the president and the vice president don't seem to agree. Obama has long supported civil unions but not marriage equality.

"This is the president's policy, but it is evolving," Biden said.

Earlier this week, Obama signed into law a measure that repeals the military's ban on gays and lesbians serving openly.

At a press conference following the signing event, ABC's Jake Tapper gave the president a chance to explain whether his views on gay marriage had changed in light of the repeal of "don't ask, don't tell."

"Is it intellectually consistent to say that gay and lesbians should be able to fight and die for this country, but they should not be able to marry the people they love?" Tapper asked.

"My feelings about this are constantly evolving," Obama replied. "I struggle with this. I have friends, I have people who work for me who are in powerful, strong, long-lasting gay or lesbian unions and they are extraordinary people. And this is something that means a lot to them and they care deeply about."

"At this point, what I've said is that my baseline is a strong civil union that provides them the protections and the legal rights that married couples have and I think that's the right thing to do," he added.

"But I recognize that from their perspective it is not enough. I think we are going to continue to debate and I personally am going to continue to wrestle with going forward," Obama said.

"It's good to hear his views are not solidly where they have been, but he's still not there on marriage," Brian Moulton, chief legislative counsel of the Human Rights Campaign, told The Washington Post.