Obama: Same-sex marriage should be legal

President Obama became the first U.S. president to endorse same-sex marriage today, telling ABC News that it "should be legal."

"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 ABC's Good Morning America.

After years of what he had called an "evolving" view of the issues, Obama said family and friends gradually persuaded him that gay and lesbian couples should be treated the same as heterosexual ones.

Facing a re-election bid in which gay rights are a hot button issue, Obama also said his endorsement is a personal view, and that states should set their own marriage laws. The interview took place a day after voters in North Carolina approved a constitutional ban on gay marriage.

His comments also came within a few days of pro-gay marriage statements by Vice President Biden and Education Secretary Arne Duncan, increasing pressure on Obama from gay rights supporters.

ABC News broke into regular programming to report Obama's comments.

Mitt Romney, Obama's likely opponent in the Nov. 6 election, told a Denver television station he doesn't agree with Obama's assessment of gay marriage.

"When these issues were raised in my state of Massachusetts I indicated my view which is I do not favor marriage between people of the same gender and I don't favor civil unions if they are identical to marriage other than by name," the former governor said. "My view is that domestic partnership benefits, hospital visitation rights and the like are appropriate but the others are not."

Aides said Obama intended to make the announcement before the Democratic convention in early September. But the intense media scrutiny given to the comments by Biden and Duncan pushed up the timetable.

They also said the gay marriage issue would not be a major part of their campaign, and do not know how or if it will affect the outcome of the election.

That said, the Obama re-election team posted video of the ABC interview on its campaign website.

Gay rights organization praised the president's announcement. The Human Rights Campaign, which has long lobbied Obama to take such a step, said Obama "made history by boldly stating that gay and lesbian Americans should be fully and equally part of the fabric of American society."

HRC President Joe Solmonese said Obama's "words will no doubt inspire thousands more conversations around kitchen tables and in church pews," promoting equality for gay couples.

The Family Research Council, a conservative group, called Obama's decision disappointing, but not surprising. FRC President Tony Perkins predicted that the president would suffer for it at the ballot box.

"As demonstrated by yesterday's overwhelming vote in North Carolina, redefining marriage remains outside the mainstream of American politics," Perkins said. "Especially in the critical battleground states and among minority voters."

Perkins said said that 10 of 16 battleground states that have "marriage amendments" could be at risk after Obama's announcement. "Today's announcement almost ensures that marriage will again be a major issue in the presidential election," Perkins said.

Once an opponent of gay marriage, Obama said he changed his views in part because of the "incredibly committed monogamous relationships, same-sex relationships" he has seen among friends and staff.

Obama said his views also changed as he worked to end the military ban on openly gay servicemembers, the former policy known as "don't ask, don't tell."

Views of gay marriage also tend to be "generational," Obama said, telling Robin Roberts of ABC that most young people he has met -- even very conservative Republicans in college -- tend to be more accepting of same-sex couples.

Obama said daughters Malia and Sasha believe discrimination against gay marriage "doesn't make sense to them and frankly, that's the kind of thing that prompts a change in perspective."

First lady Michelle Obama has also shaped his outlook, Obama said.

"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.

The president said he and Mrs. Obama "are both practicing Christians and obviously this position may be considered to put us at odds with the views of others."

"But, you know, when we think about our faith, the thing at root that we think about is, not only Christ sacrificing himself on our behalf," he added, "but it's also the Golden Rule, you know, treat others the way you would want to be treated."

Obama's decision is drawing a variety of strong reactions on social media.

ABC News, meanwhile, prepared a handy "timeline" of Obama statements on gay marriage:

FEBRUARY 1996: "I favor legalizing same-sex marriages, and would fight efforts to prohibit such marriages," reads a typed, signed statement from then-Illinois state senate candidate Obama in response to a questionnaire by the Chicago LGBT newspaper "Outlines." White House Communications Director Dan Pfeiffer later publicly disavowed the statement, claiming in June 2011 that the questionnaire was "actually filled out by someone else."

OCTOBER 2004: " What I believe is that marriage is between a man and a woman … What I believe, in my faith, is that a man and a woman, when they get married, are performing something before God, and it's not simply the two persons who are meeting," then-U.S. Senate candidate Obama said in an interview with WTTW Chicago public television.

"That doesn't mean that that necessarily translates into a position on public policy or with respect to civil unions. What it does mean is that we have a set of traditions in place that, I think, need to be preserved, but I also think we need to make sure that gays and lesbians have the same set of basic rights that are in place.

"I don't think marriage is a civil right," Obama said when asked whether there's an inherent right to marry.

OCTOBER 2010: "I have been to this point unwilling to sign on to same-sex marriage primarily because of my understandings of the traditional definitions of marriage," President Obama said during an interview with liberal bloggers. "But I also think you're right that attitudes evolve, including mine. And I think that it is an issue that I wrestle with and think about because I have a whole host of friends who are in gay partnerships."

DECEMBER 2010: "My feelings about this are constantly evolving. I struggle with this. At this point, what I've said is, is that my baseline is a strong civil union that provides them the protections and the legal rights that married couples have," Obama said in response to a question from ABC's Jake Tapper at a White House press conference.

"I recognize that from their perspective it is not enough, and I think is something that we're going to continue to debate and I personally am going to continue to wrestle with going forward," he said.

JUNE 2011: "The president has never favored same-sex marriage. He is against it. The country is evolving on this, and he is evolving on it," Pfeiffer told progressive activists at the Net Roots Nation conference.

JUNE 2011: "I think it's important for us to work through these issues because each community is going to be different, each state is going to be different," Obama said when asked during a White House press conference about New York becoming the latest state to legalize same-sex marriage.

"I think what you're seeing is a profound recognition on the part of the American people that gays and lesbians and transgender persons are our brothers, our sisters, our children, our cousins, our friends, our co-workers, and that they've got to be treated like every other American," he said. "And I think that principle will win out. It's not going to be perfectly smooth, and it turns out that the President -- I've discovered since I've been in this office -- can't dictate precisely how this process moves."

OCTOBER 2011: "I'm still working on it," Obama said when asked by ABC's George Stephanopoulos whether he would move from supporting civil unions for same-sex couples to supporting gay marriage.

"I probably won't make news right now, George. But I think that there's no doubt that as I see friends, families children of gay couples who are thriving, you know, that has an impact on how I think about these issues."