President Barack Obama on Wednesday became the first sitting president to endorse same-sex marriage, pushing the controversial issue of gay rights to the forefront of presidential campaign.

“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 said during an interview with ABC News.

His comments came a day after voters in battleground state North Carolina soundly rejected same-sex marriage and after Vice President Joe Biden on Sunday said he was comfortable with gays marrying.

Obama said he has “been going through an evolution on this issue.”

The president had previously believed civil unions were sufficient, but he said he came to believe it was not enough and that people in same-sex relationships should be able to “commit themselves in a marriage.”

Obama’s statement put him in stark contrast to his Republican opponent, former Massachusetts Gov. Mitt Romney, who supports a constitutional amendment banning same-sex marriages.

“I believe that marriage is between a man and a woman,” said Romney, who was campaigning in Oklahoma City on Wednesday.

“This is a very tender and sensitive topic,” Romney said, “as are many social issues. But I have the same view I’ve had since, well, since running for office.”

Some local conservatives believe Obama’s decision will bring voters out against him in November.

“This could spell doom for President Obama’s re-election,” said Phil Burress, president of Citizens for Community Values, a southwest Ohio group that has opposed gay rights, casinos and pornography.

“Once you legalize same- sex marriage it will be in the schools and your children will be taught that homosexuality is normal, and it’s not,” Burress said.

Rob Scott, chairman of the Montgomery County Republican Party, said Obama is trying to appeal to the liberal base of the Democratic Party.

“I think it’s a huge mistake for him and his campaign,” Scott said. “At the same time he’s turning off mainstream voters and motivating the hard-core Christian right to support Gov. Romney.”

Mark Owens, chairman of the Montgomery County Democratic Party, believes Obama’s view will energize supporters of equal rights for gays and lesbians and those on the Christian right who oppose them.

“I’m pleased that (Obama’s) come around to support a basic human right,” Owens said.

Obama’s announcement thrilled Dayton-area gay rights activists.

“To have a sitting president come on board, wow! What progress we’ve made,” said Jim McCarty, a longtime area activist. “I think people who are interested in individual liberty should see this as a step forward.”

“To say the least, I’m thrilled that President Barack Obama has come out and said what he said in support of marriage equality. I’m glad he has evolved to this place and I certainly hope others can do the same,” said the Rev. Mike Castle, pastor of Cross Creek Community Church.

Thirty-two states, including Ohio, have voted down same-sex marriage.

Voters overwhelmingly passed a gay marriage ban in 2004 with nearly 62 percent of the vote. The issue passed in 87 of Ohio’s 88 counties. Athens County, home of Ohio University, was the only county where the issue failed.

Pro-gay rights activists are now trying to put another issue on the Ohio ballot in 2013 to overturn the 2004 vote.

Polls find Americans to be increasingly supportive of the idea of same-sex marriage, with a new Gallup poll showing 50 percent of all adults favor legalizing it. Six states and the District of Columbia currently allow same-sex marriage, and two others states have same-sex marriage laws that are on hold pending possible referendums to overturn them.

Lawmakers reacted to Obama’s message largely along party lines on Wednesday.

House Speaker John Boehner, R-West Chester Twp., told Fox Business that he has always believed a marriage is between a man and a woman.

“Republicans here on Capitol Hill are focused in on the economy,” said Boehner.

Sen. Sherrod Brown, D-Ohio, one of a handful of U.S. representatives who voted against the Defense of Marriage Act in 1996, applauded the news.

“What has made America special throughout our history is the constant effort to secure rights for all of our citizens,” the Ohio Democrat said. “Our LGBT (lesbian, gay, bisexual, transgender) friends, co-workers, and neighbors should have the same rights enjoyed by all Americans.”

The Rev. Hence Coats, pastor of Pleasant Green Baptist and president of the Dayton Baptist Ministers Alliance, said voters will likely judge Obama on more than just the issue of same-sex marriage. But Coats said he does not accept Obama’s view.

“I accept marriage to be a husband and a wife, a man and a woman,” said Coats. “I disagree with same-sex marriage because of the word of God.”

Staff writer Jessica Wehrman, The Associated Press and the New York Times News Service contributed to this report.