WASHINGTON, D.C.—President Obama, in an interview with ABC News' Good Morning America that will be broadcast in its entirety tomorrow, has expressed his personal belief that "same sex couples should be able to get married." The interview with ABC's Robin Roberts was taped Wednesday afternoon, and it didn't take long for the president's "clarification" of his position to hit the wires. It's breaking big on television at the moment and is gaining traction online.

However the decision came about, it certainly marks a significant leap in the president's evolution on the issue. According to pundit Sam Stein, writing for HuffPo, "The statement constitutes an act of political bravery on the president's behalf, as well as a major victory for the gay rights community, which has been pushing him to declare his support for marriage equality for several years. With the issue back in the news this week, the pressure intensified."

That pressure, of course, came courtesy of Vice President Biden, who put a huge spotlight on his boss on NBC's Meet the Press last Sunday when he expressed his own comfort with same-sex marriage. Education Secretary Arne Duncan doubled down the next day, and from there the pundit class glommed onto it, many seeing it as a major opening skirmish in the presidential election.

They may now be correct. In coming out firmly on the side of same-sex marriage, the president has drawn one of the clearest and most definitive lines in the political sand that he could do himself. Unless there is some inexplicable walking back of the president's position yet to come, Mitt Romney will now have to decide if he is on the side of a vocal and virulent element in the Republican Party that believes surrendering on same-sex marriage is tantamount to cultural suicide, or if he understands that same-sex marriage is inevitable. It is also impossible to see how he would be able to prevaricate on the issue, either, since the president's new position—which is being spun as a clarification of a position with no "daylight" between it and Biden's—seems so clear. 

Acknowledging once again that he had been "going through an evolution on this issue," the president also said he had always been "adamant" that "gay and lesbian Americans should be treated fairly and equally" and has always "stood on the side of broader equality for the LGBT community.

"I'd hesitated on gay marriage," he explained, "in part because I thought civil unions would be sufficient; that is, something that would give people hospital visitation rights and other elements that we take for granted," and added that he was also sensitive to the fact that the word "marriage" is one that "evokes very powerful traditions and religious beliefs and so forth" in many people.

But then he said, "I have to tell you that over the course of several years as I have talked to friends and family and neighbors when I think about members of my own staff who are in incredibly committed monogamous relationships, same-sex relationships, who are raising kids together, when I think about those soldiers or airmen or marines or sailors who are out there fighting on my behalf and yet feel constrained—even now that Don't Ask Don't Tell is gone, because they are not able to commit themselves in a marriage—at a certain point I’ve just concluded that for me personally it is important for me to go ahead and affirm that I think same-sex couples should be able to get married,” Obama told Roberts.

Sure, the president's no doubt unconscious reference to "we" when referring to people who takes things for granted sticks in the craw, and reminds us that the larger dynamic remains one of "us and them," and it is curious that the president felt compelled to utter "for me" twice, but at least in his ongoing evolution the president continues to lead in the right direction.

Now if we could just convince him to come out against obscenity laws. Anyone have Biden's cell phone number?

Excerpts from the interview are also scheduled to air Wednesday night on ABC’s World News with Diane Sawyer.