WASHINGTON -- On the fence no longer, President Barack Obama declared his unequivocal support for gay marriage Wednesday, a historic announcement that gave the polarizing social issue a more prominent role in the race for the White House.
The announcement was the first by a sitting president, and Republican challenger Mitt Romney swiftly disagreed with it. "I believe that marriage is between a man and a woman," he said while campaigning in Oklahoma.
Gay-rights advocates cheered Obama's declaration, which they had long urged him to make. Beyond the words, one man who married his gay partner in Washington, D.C., was stirred to contribute $25 to the president's campaign.
"Making a contribution is the best way to say thank you," Stuart Kopperman said.
Obama revealed his decision after a series of events that made clear that the political ground is shifting.
He once opposed gay marriage but more recently had said his views were "evolving."
In an interview with ABC in which he blended the personal and the presidential, Obama said "it wouldn't dawn" on his daughters, Sasha and Malia, that some of their friends' parents would be treated differently than others. He said he also thought of aides "who are in incredibly committed monogamous same-sex relationships who are raising kids together."
Obama added that he thought about "those soldiers or airmen or Marines or sailors who are out there fighting on my behalf, and yet feel constrained even though now that 'don't ask, don't tell' is gone because they're not able to commit themselves in a marriage."
The president said he is taking a personal position. Aides said that his shift will not affect current policies and that he continues to believe that marriage is an issue best decided by states.
"I have hesitated on gay marriage in part because I thought that civil unions would be sufficient," Obama said in the interview. He added, "I was sensitive to the fact that for a lot of people, the word marriage was something that evokes very powerful traditions, religious beliefs and so forth."
Now, he said, "it is important for me personally to go ahead and affirm that same-sex couples should be able to get married."
He spoke on the heels of a pair of events that underscored the sensitivity of an issue that has long divided the nation.
Vice President Joe Biden said in an interview Sunday that he is comfortable with gay people marrying, a pronouncement that instantly raised the issue's profile. White House aides insisted that Biden hadn't said anything particularly newsworthy, but gay-rights groups cited Biden's comments in urging the president to announce his support.
On Tuesday, voters in North Carolina -- a potential battleground in the election -- approved an amendment to the state constitution affirming that marriage is a union of a man and a woman.
Additionally, several of the president's biggest financial backers are gay, and some have urged him to declare his support for same-sex marriage.
Senior administration officials said Obama concluded this year that gay couples should have the right to legally marry and had planned to make his views public before the Democratic National Convention in early September. They conceded that Biden's comments accelerated the timeline.
As recently as eight years ago, conservatives in several states maneuvered successfully to place questions related to gay marriage on the Election Day ballot as a way of boosting turnout for President George W. Bush's re-election.
Now, nationwide polling suggests increasing acceptance of gay marriage. In a national survey released by Gallup this month, 50 percent of respondents said it should be legal, and 48 percent were opposed.
Democrats favored it by a ratio of roughly 2-to-1, while Republicans opposed it by an even bigger margin. Among independents, 57 percent expressed support, and 40 percent were opposed.
Whatever the polls say, the political crosscurrents are tricky. Some top aides argued that gay marriage is toxic at the ballot box in competitive states like North Carolina and said the vote there this week shows that opposition to gay marriage is a rallying point for Republicans.
Shifting his emphasis, even briefly, could also open Obama up to Republican criticism that he is taking his eye off the economy.
Yet Democratic supporters say Obama's decision could energize a large segment of the party, including young people. He could also appeal to independent voters.
By Wednesday night, the Obama campaign had e-mailed a clip of the interview and a personal statement from the president to its vast list of supporters.
The decision also creates an area of clear contrast between Obama and Romney as he argues that he has delivered on the change he promised four years ago.
The golden rule
Obama said first lady Michelle Obama was involved in his decision and joins him in supporting gay marriage.
"In the end, the values that I care most deeply about and she cares most deeply about is how we treat other people," he said.
Acknowledging that his support for same-sex marriage may rankle religious conservatives, Obama said he thinks about his faith in part through the prism of the golden rule -- treating others the way you would want to be treated.
"That's what we try to impart to our kids and that's what motivates me as president, and I figure the most consistent I can be in being true to those precepts, the better I'll be as a dad and a husband and hopefully the better I'll be as president," Obama said.