For such a momentous announcement, President Obama surely picked an interesting way to break the news.

Obama’s disclosure on Wednesday that he supports same-sex marriage came not in a news conference, not in a policy address and not in a campaign event, but in an interview with the co-host of a morning talk show.

The second-rated morning talk show.

And he didn’t talk with the co-host most closely associated with politics, either. The first statement by a president supporting the union of same-sex couples was made to Robin Roberts of “Good Morning America,” not her morning TV co-pilot, George Stephanopoulos, the former political operative.

Obama decided that he would announce his support for gay marriages after years of maintaining that his views on the issue were still “evolving.” His fence-straddling position appeared to become increasingly untenable in the wake of Vice President Biden’s public proclamation of support on Sunday’s “Meet the Press” and subsequent declarations by White House aides that there was no difference between the president’s and vice president’s views on the issue.

ABC News spokesman Jeffrey Schneider said Roberts was chosen by the White House and the president for the interview, which caught Roberts by surprise.

On Wednesday, she was scheduled to appear on ABC’s “The View” after “GMA” to help her mother, Lucimarian Roberts, promote her newly published autobiography.

She canceled the appearance when the White House called to offer an exclusive interview with Obama. White House press secretary Jay Carney did not respond to a request for comment.

The network had an inkling of what the president wanted to talk about after Biden broached the subject Sunday, Schneider said. “It’s very much been in the air all week, so when the interview was set up, it was obvious to all that that was going to be the central question.”

The White House knew Roberts, Schneider said, from a series of interviews with the president that began when she became the first journalist to interview him on the night of his inauguration. “She’s been direct but fair,” he said. “That’s a very large part of it.”

But another part may have been that, unlike Stephanopoulos — an inside-the-Beltway figure — Roberts offered a “warmer, gauzier” and less combative presence, said Frank Sesno, a former CNN White House correspondent who is now director of the School of Media and Public Affairs at George Washington University. “If you’re the White House and you have to deal with something this white-hot, do you want to engage this as a news story or as conversation across the back of the fence?”

Roberts is amiable on TV, and having her across from the president suggested a soft and easy conversation, rather than a major policy announcement, said Fred Sainz, a spokesman for the Washington-based Human Rights Campaign, the largest gay and lesbian civil rights organization. That she is a woman, a breast-cancer survivor and the co-host of a morning program that does not regularly feature battles among talking heads helped enhance this effect.

What’s more, Roberts is African American, which might blunt some of the opposition to gay marriage among African Americans, Sainz said.

“I thought the selection of Roberts was genius,” he said. “She comes across as the neighbor you’d be happy to have a cup of coffee with. That’s the way to frame this issue, as an ongoing conversation with the American public.”

That is roughly how the interview played, with the president winding through his feelings on the issue, with references to his wife and children, rather than making blunt statements about it.

Roberts mostly let the president ramble, at least in the clips of the interview provided by ABC News in advance of broadcast.

“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.

He added “You know, Malia and Sasha, they have friends whose parents are same-sex couples. There have been times where Michelle and I have been sitting around the dinner table and we’re talking about their friends and their parents, and Malia and Sasha, it wouldn’t dawn on them that somehow their friends’ parents would be treated differently. It doesn’t make sense to them and, frankly, that’s the kind of thing that prompts a change in perspective.”