Ohio Sen. Rob Portman (R) is one of his party's leading fiscal hawks and was on the very short list of vice-presidential candidates vetted by 2012 presidential nominee Mitt Romney. But "now, the prominent Ohio conservative will be known for something else: Reversing his hard-line position against gay marriage," says CNN's Dana Bash. On Thursday night, several Ohio newspapers and CNN reported that Portman was becoming the first sitting Senate Republican, and one of a very few GOP federal officeholders, to openly support same-sex marriage.

Portman said his "change of heart" was based on personal experience: Two years ago, his 21-year-old son came out to him and his wife, Jane — explaining, Portman says, that being gay "was not a choice, it was who he is, and that he had been that way since he could remember."

It allowed me to think of this issue from a new perspective, and that's of a dad who loves his son a lot and wants him to have the same opportunities that his brother and sister would have — to have a relationship like Jane and I have had for over 26 years. [Portman, via The Cleveland Plain Dealer]

This is a sharp change of position for Portman, who voted for the 1996 Defense of Marriage Act (DOMA) in the House and has consistently backed legislation expanding gay rights — but he was never a leading GOP social conservative. Still, same-sex marriage advocates welcomed the U-turn.

"If there was any doubt that the conservative logjam on the issue of civil marriage for committed gay and lesbian couples has broken, Sen. Portman's support for the freedom to marry has erased it," says Log Cabin Republicans executive director Gregory Angelo. "We also applaud and respect the senator's decision as a person of faith who recognizes that there is a Christian case as well as a conservative case for marriage equality."

"Republicans don't get any more mainstream" than Portman, so "this is huge news," says Paul Constant at Seattle's The Stranger. Still, it's a little disappointing that "Portman couldn't do the full monty" — he says that gay marriage should be a state-by-state issue, even as he backs striking down the part of DOMA that denies federal benefits to legally married gay couples. In any case, "it'll be interesting to see how Republicans treat this news tomorrow at CPAC now that boring, reliable ol' Portman has backed off the bigot parade."

In fact, the topic of gay marriage did come up at the Conservative Political Action Conference on Thursday. On the same day Portman announced his switch, "a fellow Republican senator, Marco Rubio of Florida, who is considered a likely 2016 presidential contender, appealed to conservatives by defending his stance on key social issues, including his opposition to gay marriage," says Gerry Mullany at The New York Times.

Just because I believe states should have the right to define marriage in a traditional way does not make me a bigot. [Rubio, via The New York Times]

CPAC also hosted dueling panels on gay marriage, says David Weigel at Slate. In the one featuring National Organization for Marriage president Brian Brown and Cleta Mitchell, the American Conservative Union board member "who's credited with barring GOProud," a conservative gay-rights group, from CPAC, the panelists glumly "described a world in which intolerant liberals were forcing conservatives to defy their faiths." The other panel, "put on by the libertarian Competitive Enterprise Institute, condemned intolerance from CPAC organizers, who were giving votes away by dismissing gay voters."

"How do we let prisoners in jail get married," said conservative activist Margaret Hoover, "because they have a fundamental right, but law-abiding gay Americans who want to commit their lives to each other not get married?" [Slate]

As for Portman, it's not clear if his announcement will sway any of his on-the-fence GOP lawmakers to come forward to support gay marriage — he doesn't know of any Senate GOP colleagues who agree with him, he told The Plain Dealer — though along with his pastor he consulted the most prominent Republican same-sex-marriage backer, Dick Cheney, who advised him to "do the right thing, follow your heart."

But the Ohio senator said he was making his carefully stage-managed switch of positions now because of the looming Supreme Court ruling on DOMA and state gay-marriage laws. He expects he'll get some questions on the issue, he says, and speaking out now is partly about "getting comfortable with my position and wanting to do this before the politics of these court decisions make it more difficult to have an honest discussion." He says he won't sign on to any legal briefs in those cases, but to the extent that the justices care about where the country is on gay marriage, Portman's support will surely be taken as a sign of where the political winds are blowing.

"Cultural elites are very excited about the announcement" from Portman, says Mollie Hemmingway at Ricochet. But "this strikes me as a problematic approach" to making policy, regardless of where you stand on gay marriage. "I mean, marriage law should be changed or it shouldn't be changed — but it shouldn't hinge on the sexual attractions of one senator's son, should it?"

What if a conservative senator said, "I'm reversing my views on whether abortion should be legal because my daughter got pregnant and wished she weren't." One of the fascinating things about society today is that personal experience trumps everything else in argumentation. Very few people seem to care about fundamental truths and principles while everyone seems to care about personal experience and emotion. It's the Oprahfication of political philosophy. [Ricochet]