North America 12 January 2012 Romney's final stumbling block? Latest polling shows a dirty fight in South Carolina may be all that's holding him back from Obama. Sign UpGet the New Statesman's Morning Call email. Sign-up Having squeezed through Iowa by 8 votes and won convincingly in New Hampshire, the road ahead looks pretty clear for the former Massachusetts Governor. He has campaigned pretty much ever since 2007, and now it seems as though Mitt Romney has finally seen off all of his challengers and is focussing his sights on the presidency. One by one, Republican candidates ranging from former Speaker Gingrich, through Herman Cain the CEO of a pizza chain, Congresswoman Bachmann and Texas Governor Perry to former senator Santorum have each had their own surge (and decline) in the polls as Republicans tried to find someone that is not Mitt Romney. The problem with Romney -- or so think many Republicans -- is that he is not seen to be conservative enough for them. He's a moderate. And so they courted Bachmann, Cain, Gingrich, Paul and Santorum. All the while, Romney's ratings remained fairly constant. That was another criticism: despite having the most money and arguably the most name recognition, Romney was not "energising the base" and there was no groundswell of support for him. It was said he was Mr 25 per cent. Our Ipsos poll for Reuters of Republicans, released on the day of the New Hampshire primary, had Gov Romney on 30 per cent -- his highest since we began tracking in June 2011. The poll also shows that he has the best chance of defeating Obama in November. In a match up of Romney v Obama, the Republican is just 5 points behind the President. Ron Paul is the next closest but trails Obama by 7 points. So what does Romney have to do now to seal the nomination? The answer is simple, and the same as it has been for a while: Don't mess up. The fabled "big mo" (momentum) is clearly with him, as is the money which is vital if the race drags on. South Carolina -- the next Primary -- poses a threat in a few ways. First, voters there are more conservative than in New Hampshire and this is a demographic in which Romney suffers. However, South Carolina tends to be more "establishment" in its taste, preferring well-known and established politicians unlike "outsiders", as preferred by Iowa. Second, campaigns have a history of turning dirty in South Carolina and you can be pretty confident that Gingrich, Santorum and Paul campaigns are preparing attacks to bring down Romney in South Carolina. They'll attack him for "being liberal", flip-flopping on abortion, the similarities of his Massachusetts healthcare plan to that of Obama's controversial reform, and the current popular attack is to highlight his time at Bain where they say his job was to fire people; with high unemployment a big issue in the US that does not look good. It is unlikely, however, that these attacks will do enough to stop his move to becoming the nominee. Losing South Carolina may not even be too damaging to his campaign -- especially as he is financially and organisationally the best equipped for a long race of attrition. Rick Perry will need to do very well in order to stay in the running. Having almost dropped out after placing fifth in Iowa and focussing his attention on South Carolina -- a state in which the more conservative Texan should feel more comfortable -- his fortunes lay heavily in the results of the next primary. Speaker Gingrich too will need to think long and hard about his chances if he misses out on the top spots. Ron Paul and Rick Santorum are more likely to stay in and make this race last that bit longer before we can call Mitt Romney the Republican Presidential candidate for the 2012 race to the White House. Tom Mludzinski is Deputy Head of Political Research at Ipsos MORI › In the Critics this week Tom Mludzinski (@tom_ComRes) is head of political polling at ComRes Subscribe To stay on top of global affairs and enjoy even more international coverage subscribe for just £1 per month!