Romney Leads in South Carolina Poll; Santorum Second

A new poll shows Mitt Romney leading in South Carolina just two weeks before it holds the third vote of the 2012 Republican primary season.

The poll, conducted by CNN, found that 37 percent of likely primary voters supported Romney, 19 percent supported Rick Santorum, 18 percent Newt Gingrich and 12 supported Ron Paul. Rick Perry and Jon Huntsman trailed with 5 percent and 1 percent, respectively. The margin of error was plus or minus 4.5 percentage points.

The results point to a marked turnaround since the last polls were conducted in South Carolina in mid-December. Then, Gingrich (~37 percent) held double-digit leads over Romney (~21 percent), and every other candidate was in the single digits in the RealClearPolitics average: Paul with 8.7 percent, Michele Bachmann (who suspended her campaign on Wednesday after a poor showing in Iowa) with 6.7 percent, Perry with 5.7 percent, Huntsman with 3.3 percent and Santorum with 2.7 percent.

GOP Race Now Has Santorum Surging, Gingrich Collapsing

In just three weeks, the entire landscape of the race has changed -- partly due to the ripple effect from the Iowa caucuses, but the momentum was shifting even before that. Gingrich has all but collapsed under the weight of attack ads from super PACs affiliated with his opponents, and Santorum has surged faster and higher than even he probably imagined possible. Paul's numbers have risen less dramatically, but he made it into the top tier in Iowa by building support slowly and steadily, not through a sudden surge, and he is clearly gunning for the same thing in South Carolina, and New Hampshire for that matter.

Winning South Carolina is more important for some candidates than others. For Gingrich and Perry, it is a must if they want to stay in the race, as evidenced by the fact that they headed straight to South Carolina from Iowa, essentially ceding New Hampshire to Romney. Anything less than a win, or an extraordinarily close second-place finish on the order of Santorum's in Iowa, would be the final blow for their campaigns.

At the other extreme, South Carolina means little to Jon Huntsman, whose only hopes of competing for the nomination rest on doing well enough in New Hampshire to give him momentum going into big swing states like Florida. Even if he exceeded expectations in New Hampshire, he would be hard-pressed to make a dent in a Deep South state.

Paul, Romney and Santorum are somewhere in between. Because they were the top three finishers in Iowa, expectations are high, but their success in Iowa also gives them a cushion if they don't do quite as well in South Carolina.

This means South Carolina is not a must-win state for them the way it is for Gingrich and Perry, but it would be highly significant for any of them. If Romney wins New Hampshire -- which, according to projections by The New York Times' FiveThirtyEight blog, he has a 98 percent chance of doing -- and then goes on to win South Carolina, he will have swept the first three contests in three regions of the countrry, which would be unprecedented for a modern presidential candidate and make him extremely difficult to catch for the nomination.

If Santorum wins South Carolina, he will prove that his virtual tie in Iowa was not a fluke and solidify his status as the conservative candidate to beat. And if Paul wins, he will establish himself as a formidable opponent to Romney and underscore the growing influence of libertarianism within the Republican Party.