President Barack Obama said Wednesday he supports same-sex marriage, raising the political stakes on an issue over which Americans are evenly split.
The announcement was the first by a sitting president and put Obama squarely at odds with presumptive Republican presidential nominee Mitt Romney, who on Wednesday said during an appearance in Oklahoma, "I believe marriage is a relationship between a man and a woman."
Obama said in an interview with ABC News, "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 once opposed such marriages. He later indicated his views were "evolving."
"I had hesitated on gay marriage, in part, because I thought civil unions would be sufficient," the president said. "I was sensitive to the fact that -- for a lot of people -- that the word marriage is something that provokes very powerful traditions and religious beliefs."
But, Obama said, his thinking shifted as he witnessed committed same-sex marriages and thought about U.S. service personnel who were "not able to commit themselves in a marriage."
It was not immediately clear how the development -- which same-sex marriage advocates had long sought -- might play out at the voting booth.
A Gallup Poll released Tuesday indicated 50% of Americans believe same-sex marriages should be recognized by law as valid, with 48% saying such marriages should not be legal.
But a CNN/ORC poll, taken in late March, indicated policies towards gays and lesbians were tied for last in the most-important issues facing the country.
Obama was "disappointed" by Tuesday's vote on the issue in North Carolina, which he described as discriminatory against gays and lesbians, a spokesman said earlier Wednesday.
North Carolina voted to implement a state constitutional ban on same-sex marriage, which was already prohibited by state law. Supporters of the measure pushed for the constitutional amendment, arguing that it was needed to ward off future legal challenges.
The president said he supports the concept of states deciding the issue on their own, ABC News reported.
Obama said his daughters, Malia and Sasha, have friends whose parents are same-sex couples. "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."
Obama spoke Wednesday with ABC's Robin Roberts. The interview will appear on ABC's "Good Morning America" Thursday. Excerpts aired Wednesday evening on "World News With Diane Sawyer."
The president's stance will be among many key differences with Romney, but it is not expected to be a key talking point in his campaign.
In comments Wednesday to CNN Denver affiliate KDVR, Romney reiterated his opposition to same-sex marriage.
"And I do not favor civil unions if they are identical to marriage other than by name," Romney said during a visit to Fort Lupton. "My view is the domestic partnership benefits, hospital visitation rights, and the like are appropriate, but that the others are not."
The Family Research Council criticized Obama, and its president said on CNN's "The Situation Room" that the decision will aid Romney.
"The president, I think, has handed to Mitt Romney the one missing piece in his campaign," said Tony Perkins. "That is the intensity and motivation that Mitt Romney needs among social conservatives to win this election."
An expert on religion and politics said the move will make "an already close election even closer."
"It cuts both ways -- it activates both Democratic and Republican base voters," said John Green of the University of Akron.
Obama told ABC that some opinions on the issue are "generational."
"When I go to college campuses, sometimes I talk to college Republicans who think that I have terrible policies on the economy, on foreign policy, but are very clear that when it comes to same-sex equality or, you know, sexual orientation, that they believe in equality," he said.
First lady Michelle Obama was involved in the president's decision.
"This is something that, you know, we've talked about over the years and she, you know, she feels the same way, she feels the same way that I do," Obama said.