Every contentious campaign seems to have moments when there is conflicting evidence about which candidate, if any, has the momentum in the race.
There are some hints that Newt Gingrich is gaining ground in South Carolina, perhaps at Mitt Romney’s expense. But the evidence is not definitive yet, and this would represent a reversal of a previous trend that had shown Mr. Romney gaining ground there.
Up until about 24 hours ago, it had appeared that Mr. Romney was building his lead in South Carolina. Rasmussen Reports had shown Mr. Romney with a 14-point lead in a poll it conducted on Monday night, up from seven points in its poll from last Thursday. Likewise, InsiderAdvantage had given Mr. Romney an 11-point lead in a poll it conducted on Sunday, up from just two points in a poll it conducted Jan. 11. Because of these and other polls, Mr. Romney had been slowly but steadily gaining ground in the FiveThirtyEight forecast of South Carolina, which estimated his chances of winning the state to be 90 percent.
However, all of that polling was conducted before Monday night’s debate, in which Mr. Gingrich’s performance was generally well reviewed but Mr. Romney’s less so. Meanwhile, Mr. Gingrich received a qualified endorsement from Sarah Palin late Tuesday night, while Mr. Romney has had a reasonably tough news cycle with much attention focused on his tax returns and other controversies.
What we’d like to see is polling that postdates the debate, but we don’t have very much of it so far. A CNN poll, released on Wednesday afternoon, gave Mr. Romney a 10-point lead over Mr. Gingrich, which is fairly typical of other recent surveys, but only one-fifth of its interviews were conducted after the debate.
Potentially more interesting is an automated poll conducted by the firm 20/20 Insight L.L.C., which polled on behalf of the liberal-leaning judicial reform group Justice at Stake.
Chris Huttman, who conducted the poll, provided FiveThirtyEight with a breakout of results from each of the three nights of interviewing in the poll. Although Mr. Romney had a double-digit lead in interviews conducted on Sunday and Monday night, Mr. Gingrich was actually ahead of Mr. Romney by five points in interviewing conducted on Tuesday night. However, the sample sizes on the daily samples are extremely small, leading to a larger margin of error and making it hard to calibrate demographic weights, so this evidence is tenuous at best.
If you want additional evidence for Mr. Gingrich’s momentum, you have to look beyond South Carolina and toward national polls. A Rasmussen Reports national survey, conducted entirely on Tuesday night, showed Mr. Gingrich closing to within three points of Mr. Romney nationally, much closer than other recent polls showed Mr. Gingrich.
The Gallup national tracking poll, meanwhile, still shows Mr. Romney with a 17-point lead. However, that is down from a 23-point lead in the poll it released on Monday, and most of Gallup’s data still precedes the debate.
It is not surprising that there is confusing evidence in the polling given the conflicting currents of momentum in the Republican race right now. These include voter reactions to the debate, Mr. Romney’s big win in New Hampshire last week, Jon M. Huntsman Jr.’s ending his campaign and endorsing Mr. Romney, the series of attacks against Mr. Romney, and the backlash that these attacks have engendered among some influential Republicans.
What seems safer to conclude is that no candidate other than Mr. Romney or Mr. Gingrich is likely to win in South Carolina. If Rick Santorum had gotten a major boost by winning the support of evangelical groups over the weekend, for instance, we might have expected to see some clearer evidence of that by now. Mr. Santorum has moved ahead of Ron Paul and into third place in our forecasts, but his overall trajectory has been quite flat.
Mr. Paul, meanwhile, is now projected to win about 15 percent of the vote in South Carolina, an estimate improved by his strong showing in New Hampshire. But the lift he got from New Hampshire now seems to be fully accounted for by the South Carolina polls.