What if Newt Gingrich wins the South Carolina primary?It's not that far-fetched, even though the Beltway press has written him off as a serious contender. Mitt Romney is leading Gingrich 29 to 24 percent in the state, according to Public Policy Polling, which means Newt is within striking distance.Would conservatives coalesce around him as the anti-Mitt? What if Rick Santorum (14 percent in the poll, a point behind Ron Paul) and Rick Perry (6 percent) were forced to drop out? Most of their supporters might gravitate to Gingrich, giving him a fighting chance in Florida and beyond. It doesn't help Newt that 150 Christian leaders meeting in Texas on Saturday endorsed Santorum, although how much clout they have remains to be seen. (How's this for spin? A Gingrich statement says, "Conservative evangelical leaders spoke very clearly today that Mitt Romney will not be the nominee. It is encouraging for the Republican Party to have two choices in Newt Gingrich and Rick Santorum.")The odds are certainly against a Newt victory, given all the baggage that Gingrich carries. But after getting buried under negative ads by a pro-Romney Super PAC in Iowa, he is returning the favor in South Carolina, courtesy of $5 million to the pro-Gingrich Super PAC from casino mogul Sheldon Adelson. (Yes, Newt has been forced to ask that the ads be fixed or taken down after fact-checkers shredded it, but he gets to have it both ways: taking the high ground while Romney gets pouned.)The Public Policy folks find good news for Romney when they drill down, particularly in the strong focus on financial matters: “39% say jobs and the economy are their top issue, closely followed by 34% who pick government spending and reducing the debt. Asked who they trust most on economic issues 35% pick Romney to 25% for Gingrich.What about South Carolina's reputation as a cauldron of conservatism with a strong evangelical base? Turns out only 4 percent say social issues are most important to them, and on that subject, “Santorum only beats Romney 23-21 with Gingrich at 19% and Paul at 14%. Romney's also basically running even with evangelicals, getting 27% to 28% for Gingrich and 17% for Santorum.”These numbers suggest that Gingrich is on target in painting Romney as a job-destroying capitalist from his Bain days (though Newt doesn’t seem to be peddling a jobs plan of his own). It also suggests that his growing emphasis on Romney’s record as a pro-abortion governor of Massachusetts won’t get much traction, not when people are worried about pink slips. Unemployment in South Carolina is 9.9 percent, higher than in Iowa or New Hampshire.A couple of warning signs for Romney: his net favorability has dropped 7 points in the last week (to 57/33), while Gingrich’s has risen 4 points (to 51/37). And 58 percent of the primary voters surveyed don’t want Romney to be the nominee.In that case, they had better throw their collective weight behind one rival. Gingrich picked up on the point Friday, telling a group of Republicans: “If we end up splitting the conservative vote, we’re going to stumble into nominating somebody that 95 percent of the people in this room would be very uncomfortable with.”A self-serving argument, to be sure. But unless enough South Carolina conservatives buy it, next Saturday’s primary could begin the Romney coronation.