Who is the leader of the “Not-Romney” movement within today’s GOP?

Is it Newt Gingrich, whose surge in the South Carolina opinion polls puts him within striking distance of front-runner Mitt in tomorrow’s vote?

Is it Ron Paul, whose dedicated core of “hard-money” but isolationist supporters gives him 15 to 20% in every Republican contest?

Or is it Rick Santorum, recently endorsed by a raft of Christian evangelical leaders?

For my dollar, the leader is Sarah Palin, whose endorsements continue to carry more weight among conservatives than any other national figure and who is well-positioned to play a king-making role in the 2012 elections similar to her “Mama Grizzly” performance guiding the Republican surge in 2010.

How did this happen? She’s not running. She’s in Alaska. Since declaring herself a non-candidate at the beginning of October, Mrs. Palin has kept a pretty low profile.

Until recently, her main contribution to the political discourse was castigation of “Congressional insider trading,”a practice exposed by one of her SarahPac advisors, Hudson Institute fellow Peter Schweitzer, in a new book called “Throw Them All Out.” That expose gave rise to competing Congressional reform bills, the best of which would make it illegal for Federal legislators to routinely do what Raj Rajaratnam.

Before that, at a much-noted speech to Iowa Tea Partiers back in August, Mrs. Palin the political wordsmith injected “crony capitalism” into the public discussion. That phrase has captured the corrupt connivance between Big Business and Big Government which challenged the anti-business protestations of the “Occupy” crowd.

Recent weeks have seen a resurgence of the Grizzly factor. In a December 1 appearance, as a Fox News commentator on the GOP race, Mrs. Palin uttered one sentence in praise of Rick Santorum’s “ideological consistency.” Immediately the former Pennsylvania senator’s numbers began to climb.

By January 4 Mr. Santorum tied — or maybe, when the final figures are out, bested — Governor Romney in the Iowa straw poll, an accomplishment that seasoned observers attributed to good timing and months of hard work in Iowa’s rural precincts. Palin-watchers had their own theory of causality.

This week Mrs Palin was at it again. As Suzi Parker described it at the Washington Post:

[Mrs. Palin] told Fox News’s Sean Hannity on Tuesday night that if she was a South Carolinian, she would vote for Newt Gingrich. It wasn’t a straight endorsement, she stressed, but Palin simply believes the primary should be hard-fought and not easily handed to Mitt Romney on a silver platter.

“Iron sharpens iron, steel sharpens steel,” Palin said.

At RealClearPolitics, Palin-watcher Scott Conroy asked the Gingrich camp how significant they considered Mrs. Palin’s support to be? “Big,” was the answer of a top aide to the former speaker.

Now polls show Mr. Gingrich surging, as the not-Romney vote coalesces, at least for now, around the one-time college professor and speaker.

Mrs. Palin even went on Hannity’s radio program Thursday to lambast the “lame-stream media” for publishing an interview with Mr. Gingrich’s disgruntled “ex”, a rhetorical axe Mr. Gingrich himself swung at CNN’s John King later that night, with telling effect.

So what is next for the politician The New York Sun calls “the alert Alaskan”? For now, to keep the GOP pot boiling.

She is able to do so because millions think she is brilliant, incorruptible, and knows how to lead. Many of them hope she will still get into this race, but she has insisted that in this political season she will make her contribution from the side-lines with the goal of a Republican president in 2013.

Mr. Korn, founder of Jewish Americans for Sarah Palin, is a Philadelphia-based newspaperman who blogs at JewsForSarah.com.