Mitt Romney won the non-binding Iowa Straw Poll earlier this month. He’ll almost certainly win the binding Iowa Caucus in January (or in December, if the primary calendar keeps creeping toward Turkey Day). He’s neck-and-neck with Mayor Giuliani in New Hampshire. Yet the former Massachusetts governor can’t seem to get so much as a toehold in the third of the Big Three early states, South Carolina.

Why can’t Mr. Romney make any headway in the Palmetto State? It’s a puzzle the Romney campaign might want to solve, because if it can’t lock down all three early states, its ultra-targeted primary strategy simply stops making sense.

No one from the Romney campaign would return calls or emails yesterday to discuss what’s gone wrong, but a poll published by Rasmussen Reports on Wednesday gives the flavor of things: Mr. Romney is in fourth place, with just 10% of the Republican primary vote in South Carolina. Senator McCain, whose presidential campaign has all but collapsed, is at 14% in the poll; Mr. Giuliani is at 21%, and the yet-to-declare Fred Thompson leads with 23%. And this, it should be noted, is one of the better polls out of the state for Mr. Romney. Most have him in single digits.

Plenty of explanations could be offered for this poor showing, but none seems satisfactory. Mr. Romney has spent money in South Carolina. The state’s largest newspaper, the State, reports that he’s spent more than $1 million there already on ads and organization. He’s spent time in the state. He started coming in 2005 and has courted the major players extensively.

Then, of course, there’s what an associate professor of political science at Winthrop University in South Carolina, Scott Huffmon, calls “the Mormon thing.” Mr. Huffmon, who directs the Winthrop/ETV Poll, says that while the issue “isn’t talked about a lot in the open … it is lurking behind the scenes.” The vast majority of South Carolinians (upward of three-quarters) describe themselves as “very religious.” And by far the plurality of those religious folks are Southern Baptists. And if you want to know what Southern Baptists think of Mormons — well, just take a look at the Web site of the Southern Baptist Convention, type “Mormon” into the search box, and call me when your eyes stop bleeding.

Still, the Mormon explanation is less than convincing. Gallup did a poll earlier this year asking Americans whether they would vote for a presidential candidate belonging to one of several minority groups, including Catholic, black, Hispanic, Jewish, Mormon, gay, and atheist. Only 72% said they would vote for a Mormon (compared to 95% for a Catholic and 92% for a Jew). But the number who would do so wasn’t particularly lower in the South, at 68%, than in, say, the Midwest, at 65%, where Mr. Romney has managed to do decently.

So what’s left? It all may come right down to personality.

One South Carolina Republican insider, who was once up for grabs but is now supporting a non-Mitt candidate, explained it to me this way: “He left me cold.” That sentiment was shared by a South Carolina political consultant, Chip Felkel. Mr. Romney is “too slick, too focus-grouped,” Mr. Felkel told me.

While the Mormon issue might affect 5% to 10% of the Republican primary electorate, it’s mostly just a “deal closer” for voters who don’t want to support Mr. Romney anyway.

Mr. Romney’s been able to succeed elsewhere, Mr. Felkel speculates, because he’s been dealing with a specific breed of voter. “The Iowa voter and the New Hampshire voter have developed this terrific self-regard,” Mr. Felkel said. “If someone does not come out there and kiss their rear end all the time, they punish them.” Mr. Romney’s been puckering up.

South Carolina voters simply don’t work like that.

The problem for Mr. Romney is that if he wins only one or two out of the three early states, he won’t enter the January 29 Florida primary and the February 5 20-plus-state primary as the undisputed front-runner. In that case, there’s a nationwide race on between him and Messrs. Giuliani and Thompson. And both of his opponents are far stronger nationwide.

The straw poll win may have been nice for Mr. Romney. But without the ability to compete down South, it may prove to have been something less than a straw in the wind.