It's easy for a Republican senator to argue in the abstract that gays should be denied equal opportunity to marry. But it's a lot tougher when one of those gay Americans is your own son.

That's the gist of the message from Rob Portman, the veteran Ohio lawmaker and recent short-listed vice-presidential prospect, who has decided to (a) reveal the sexual orientation of 21-year-old Will Portman, and (b) mark the occasion by reversing his long-stated opposition to gay marriage. He thus becomes the first sitting Republican senator to support equality, and, in doing so, he will roil anew the turbulent intraparty debate on that fundamental issue.

In a media blitz yesterday, Portman called his reversal "a change of heart." Which is another way of saying that the personal is political.

He told CNN yesterday: "I've come to the conclusion that for me, personally, I think this is something that we should allow people to do, to get married, and to have the joy and stability of marriage that I've had for over 26 years. That I want all of my children to have, including our son," who, two years ago, "came to Jane, my wife, and I, told us that he was gay, and that it was not a choice, and that it's just part of who he is, and that's who he'd been that way for as long as he could remember."

Portman, who supported the 1996 Defense of Marriage Act, which denies federal benefits to married gays, has been reborn as a DOMA opponent. Will's orientation, he told Ohio reporters yesterday, "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."

And in a guest newspaper column, he wrote: "I wrestled with how to reconcile my Christian faith with my desire for Will to have the same opportunities to pursue happiness and fulfillment as his brother and sister. Ultimately, it came down to the Bible's overarching themes of love and compassion and my belief that we are all children of God."

Well. I bet religious conservatives will love that paragraph.

In other words, Portman's announcement will further stoke the GOP's identity crisis. The party base moralists remain unalterably opposed to gay marriage, and insist that any deviation is tantamount to a violation of traditional Christian values. They also tend to dominate low-turnout congressional primaries, and high-turnout early presidential primaries. Marco Rubio, a potential '16 candidate, gave them a nod yesterday, when he said at the Conservative Political Action Conference: "I believe that states should have the right to define marriage in a traditional way...We don't need any new ideas."

I also have to wonder whether Mitt Romney rejected Portman as a running mate because of his son. Portman said yesterday on CNN that he had been candid about his family during the veep vetting process: "I told Mitt Romney everything. That process is - intrusive would be one way to put it. But, no, yeah, I told him everything." Portman insisted that the Romney team did not view his son as a deal-breaker. How does he know this? "Because they told me."

Oh please. He really believes that?

If Portman had been nominated, his family particulars would have been laid bare. If the public had learned that he had a gay son and that he was accordingly rethinking his stance on gay marriage, the news would have dominated multiple cycles, and religious conservative enthusiasm for Romney would have been dampened even further. Indeed, if Portman had revealed the news last fall while stumping on behalf of Romney - as opposed to revealing it now, long after the campagn - he would have made life more difficult for the Republican ticket.

But by coming out (as it were) in 2013, he's giving the party three years to embrace this civil rights issue before the next presidential election - and perhaps purge itself of the social bigotry that has alienated the American mainstream. By demonstrating how the personal is political, Portman is doing his party a favor. And if Dick Cheney, with his gay daughter, can say yes to gay marriage - he reportedly advised Portman, "Follow your heart" - then anything is possible.

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