The following sentence may be the perfect expression of the absurdity of the Republican presidential race: Marital infidelity is suddenly a hot topic -- and it's great news for a thrice-wedded candidate whose current marriage grew out of an affair he had while leading a drive to impeach a president over conduct related to an extramarital relationship of his own.

In simpler terms, what this means is that the latest Herman Cain sex scandal is probably going to boost Newt Gingrich's already surging campaign.

Advertisement:

Even before Georgia businesswoman Ginger White stepped forward Monday to claim that she'd had a 13-year affair with Cain, who has been married to his wife, Gloria, for more than four decades, the Cain bubble was deflating. His total inability to handle the spotlight that came with his rise to the top of GOP polling earlier this fall had already reduced his standing and created the opening for a new Mitt Romney alternative that Gingrich has seized.

But while talk that he might actually be a threat to win the nomination had quieted, Cain still entered this week with a not-insignificant level of support. Four national polls released before Thanksgiving showed him nabbing between 14 and 17 percent of the vote, with Gingrich and Romney both in the low 20s. There isn't as much recent data available from the key early states of Iowa and South Carolina, but the most current numbers from both states also have Cain in the mid-teens. In New Hampshire, where several surveys came out just before Thanksgiving, his support has apparently fallen back into the single digits.

Cain is denying White's allegation of a prolonged affair, although in keeping with the baffling and often self-contradictory public relations strategy that has defined his campaign, his lawyer also issued a statement that framed White's story as "an accusation of private, alleged consensual conduct between adults -- a subject matter which is not a proper subject of inquiry by the media or the public." But the Cain response almost doesn't matter. On the heels of the sexual harassment allegations he faced a few weeks ago and his various face-plants since then, he's more than exhausted the average Republican's patience. As former Bush speechwriter David Frum put it on Twitter: "It's ok to claim innocence once or even twice. But after a point: you've just been innocent too damn many times."

Advertisement:

What the White story is likely to do, then, is to hasten Cain's demise to total polling irrelevance, returning him to the obscurity he enjoyed before the campaign began and for a long stretch over the summer, until Rick Perry's own meltdown nudged anyone-but-Romney conservatives Cain's way.

The main beneficiary of this figures to be Gingrich. This would be entirely consistent with the pattern that has prevailed in the GOP race so far. Every time one of the non-Romney candidates has seen his or her numbers drop, the runoff has gone to a new non-Romney option -- and never to Romney himself. Even before the White story, Cain had lost about 10 points in national surveys, with practically all of that support moving Gingrich's way. So it stands to reason that if Cain now fades from the mid-teens to the mid-single digits Gingrich will only rise higher. The resistance of the GOP base to Romney is well-established by this point. It's not that Republican voters despise him; they actually seem to like him personally. But about 75 percent of them seem to feel strongly that he's just not a good fit to lead the GOP in 2012. Otherwise, he would have broken past 25 percent long ago.

In fact, with Cain's pending demise things could get very scary for Romney in the near future. If the pattern holds and Gingrich gobbles up the bulk of Cain's support, the former House speaker could be polling in the mid-30s in national surveys in the next week or two, potentially opening up a double-digit advantage over Romney. And his numbers could look even better in some of the early states, particularly South Carolina, where one recent poll already showed Gingrich ahead of Romney by 15 points (with Cain at 17 percent).

Advertisement:

Nor does it seem likely that the Cain adultery story will also drag down Gingrich by reminding culturally conservative Republicans of the former House speaker's own adulterous past. After all, it's not as if the details of Gingrich's personal life aren't already well known, particularly among the family values crowd. But as Michelle Goldberg found in talking to some social conservative leaders recently, there seems to be an increasing willingness on the right's part to overlook Gingrich's three marriages, partly because he's concocted a compelling redemption story (copping to past failings but insisting he's a changed man since his conversion to Roman Catholicism) and partly because the desire for a consensus alternative to Romney is just that strong.

So yes, it really has come to this: We're a month away from the Iowa caucuses, and adultery may end up pushing Newt Gingrich into a clear lead over a man who's been married to the same woman without a hint of impropriety for 42 years.