Newt Gingrich, who had trailed Mitt Romney by a double-digit margin in South Carolina in several polls conducted just after the New Hampshire primary, may instead be headed to a big victory there, recent polling shows.
Mr. Gingrich leads Mr. Romney 38 percent to 30 percent in the FiveThirtyEight forecast of South Carolina, which has been updated with polling through Friday evening.
Much of the reason for the relatively clear lead for Mr. Gingrich is that he has very clear momentum in the race. In a survey conducted by Public Policy Polling, for instance, Mr. Gingrich led Mr. Romney by four percentage points in interviews conducted on Wednesday night, based on a detailed breakout of nightly results provided to FiveThirtyEight by Tom Jensen of Public Policy Polling. But Mr. Gingrich’s lead expanded to six points in interviews conducted on Thursday. And Mr. Gingrich led by 14 points in about 700 interviews conducted on Friday night, after the Thursday night debate in North Charleston and the interview given to ABC News by one of Mr. Gingrich’s ex-wives.
In primaries, especially in the early-voting states, momentum is a strong predictor of the results, and it is usually correct to give considerable weight to the most recent data.
South Carolina has been surveyed by more than a dozen distinct polling firms over the past week, and the surveys are in agreement that Mr. Gingrich gained significant ground on Mr. Romney after the Monday night debate in Myrtle Beach. If Mr. Gingrich was also helped by the Thursday night debate, as the Public Policy Polling data suggests, his margin of victory in South Carolina could be impressive — perhaps reaching into the double digits.
Nevertheless, Mr. Romney retains some chance of winning. Although momentum holds up more often than not in primaries and caucuses, there have been some important exceptions — like when Hillary Rodham Clinton won the New Hampshire primary in 2008 despite Barack Obama’s polling surge following his Iowa caucus win.
There is also an unusually large amount of disagreement in the South Carolina polls, which contributes to the uncertainty there. And those looking for hopeful signs for Mr. Romney can find a couple. First, Mr. Gingrich somewhat underperformed his polling in both Iowa and New Hampshire, perhaps as a result of his middling voter turnout operation. Second, the race appears to be much tighter — essentially a tossup — if you look solely at polls conducted using live interviewers, rather than those like Public Policy Polling that use automated scripts.
Still, the more recent the polling data, the better Mr. Gingrich tends to do in the surveys. And Mr. Gingrich has also gained considerable ground on Mr. Romney in national polls of Republicans, which makes it less likely that his polling momentum in South Carolina is a statistical fluke.
Although Florida is a stronger state for Mr. Romney than South Carolina — one where his financial position gives him an advantage in the state’s expensive media markets — a big win for Mr. Gingrich in South Carolina could rewrite the narrative of the race, potentially making Mr. Romney vulnerable there as well.