South Carolina could put Gingrich back in the hunt

When the week began, the idea of anyone but Mitt Romney claiming victory in tonight's South Carolina primary seemed fanciful. He had a 10 point lead in the polls, giving him a 90 per cent chance of victory according to Nate Silver's model. Any talk of someone else winning sounded like the wild hopes of a media keen for the nomination battle to go on as long as possible.

But no longer. As I said on Thursday, it's been a particularly bad week for Romney and a particularly good one for Newt Gingrich. Gingrich even managed to turn the one thing that seemed likely to halt his momentum – an ABC News interview with his ex-wife in which she claimed he had asked for an open marriage – into by far the strongest moment of Thursday night's debate. As he denounced ‘the destructive, vicious, negative nature of much of the news media’, the Republican audience gave him a standing ovation.

The result is that Romney's 10 point lead has turned into a similarly strong lead for Gingrich. Indeed, PPP's polling last night found him 14 points ahead, with 40 per cent to Romney's 26. Nate Silver's model (above) now gives Gingrich an 82 per cent chance of winning tonight. If he does so, he could still have a shot at the nomination, although Romney will still be the favourite.

If Gingrich does take victory in South Carolina and Rick Santorum drops out of the race – as seems likely, especially if he finishes fourth behind Ron Paul – the former Speaker could well follow it up with a win in Florida on January 31. Two losses in states that he was expected to carry until the last couple of days would certainly put a dent in Romney's ‘inevitability’. But after Florida the race could be trickier for Gingrich. Romney has a big advantage in organisation and money, and most of the next few primaries are in states where he should have an advantage: states like Nevada, Minnesota and Michigan. And in the February state where you might expect Gingrich to be strongest – Missouri – he's not on the ballot. But if Gingrich could pull off surprise wins in states like Colorado or Arizona – where he's led in recent polls – he might just be able to keep the race competitive until Super Tuesday (March 6) at least.