You know who this benefits?

In Iowa, both Romney and Paul are each up five points among likely caucus goers from a CNN/Time/ORC poll conducted at the start of December. The new survey indicates that Santorum, the former senator from Pennsylvania, is at 16% support, up 11 points from the beginning of the month, with Gingrich at 14%, down from 33% in the previous poll. Since Gingrich’s rise late last month and early this month in both national and early voting state surveys, he’s come under attack by many of the rival campaigns…

Santorum is campaigning on a shoestring budget, but he’s visited all of Iowa’s 99 counties and has made a strong pitch towards social conservative voters, who are very influential here in Iowa on the Republican side. Wednesday Santorum was up with a new radio spot on Hawkeye State airwaves touting endorsements by social conservative leaders. His pitch may be starting to pay off.

“Most of Santorum’s gains have come among likely caucus participants who are born-again or evangelical, and he now tops the list among that crucial voting bloc, with support from 22% of born-agains compared to 18% for Paul, 16% for Romney, and 14% for Gingrich,” says CNN Polling Director Keating Holland.

So there’s the long-awaited Santorum surge among social cons, who are finally giving him a first look at the perfect moment after flirtations this fall with Bachmann, Perry, Cain, and Gingrich. Two caveats, though, one minor and one major. The minor: PPP’s poll published this morning found Santorum stuck at 10 percent, still behind Gingrich and Bachmann. Are their numbers the outlier or are CNN’s? The major: According to the crosstabs, CNN only polled … registered Republicans in Iowa. That means they’re badly underestimating support for Paul, who’s cleaning up among Democrats and independents who are planning to vote in the caucuses. They polled New Hampshire too and did a bit better with that sample, including indies who are likely to vote (Romney leads Paul there by nearly 30 points), but I’m not sure the Iowa data is worth anything. Stick with PPP’s numbers for the time being: Paul 24, Romney 20, Gingrich 13, Bachmann 11.

Got an update or two coming, so stand by.

Update: WaPo quantifies the flaw in CNN’s poll: “in early Dec. Post-ABC Iowa poll, registerd GOP were 83% of potential caucusgoers, with Paul about 2X better among non-Reps.” And PPP notes that if they made CNN’s sample mistake, they’d also have had Romney ahead of Paul.

Update: Erick Erickson sees Romney’s dream coming true:

Santorum has no money or organization outside of Iowa and cannot win the nomination, but Iowans love a guy who sucks up to them and makes sure they know he loves the babies.

As a pro-lifer myself, I have to throw up a bit in my mouth that Iowa conservatives are seriously considering Rick Santorum, which will only help Mitt Romney, a guy who even after his supposedly heartfelt conversion to life put some seriously pro-abortion judges on the Massachusetts bench hiding behind the “Well it was Massachusetts for Pete’s sake” defense…

Rick Santorum is more conservative than Mitt Romney. He is a strong social conservative and has taken a lot of bullets from the left because of his stand. But he is not as strong a fiscal conservative as he claims and the real issue here is social conservatives in Iowa risk Mitt Romney’s election by supporting a guy who cannot get traction or money outside of Iowa.

Rick Santorum will not be the nominee. That’s the reality. But his rise hurts Bachmann, Gingrich, and Perry in Iowa — all of whom have better organizations and better shots beyond Iowa.

Philip Klein also imagines Romney gleefully rubbing his hands at the new dynamic. Santorum’s been following the same underpants-gnome strategy in Iowa as Huntsman has in New Hampshire:

Step one: Camp out there and become the de facto hometown favorite/Not Romney
Step two: Win
Step three: ????
Step four: Nominee!

Step three, I guess, is “momentum,” but momentum works a lot better when you have money and organization to help carry it forward. The only way Santorum becomes a real long-term threat, I think, is if he and Paul finish in the top two in Iowa and then Paul shocks Romney in New Hampshire. (Which is unlikely: Mitt’s now a 90 percent favorite there according to Nate Silver’s model.) That would leave Romney smelling like a loser and would set Santorum up for a possible win in South Carolina. Even then, I’m not sure how he’d outlast Romney in Florida and then in the long slog for delegates on Super Tuesday and beyond, but it would establish him as the lone remaining alternative to Mitt and Ron Paul for conservatives who can’t stomach either.