 aS a man endowed with an unnaturally large head and an ego to match, Newt Gingrich is frequently described as grandiose.  Last week alone, the former Speaker of the House of Representatives called himself a celebrity and boasted of commanding $60,000 (?38,000) a speech. He also suggested poor children should scrub floors to learn the work ethic and said that if elected president, he would give americans an online course in citizenship.  Yet as he stepped down from the stage after laying out his vision to Republicans from Polk County on a sleety Thursday night in Iowa, he seemed uncharacteristically unsure of himself.  a month from now Iowa will vote for a candidate to face President Barack Obama in next year's election. In the latest twist in the rollercoaster ride for the Republican nomination, Gingrich was speaking for the first time as the clear frontrunner.  "We were expecting a wave but this has been a tsunami," he said. "I have to confess this is disorienting. It's such a rapid change that we're having to rethink our own internal operations and where we are."  Gingrich has rocketed from 3% in polls two months ago to 38%. He tops three of the four key primary states - Iowa, South Carolina and Florida - and is catching up with Mitt Romney, the frontrunner in New Hampshire. In Iowa he is 15 points ahead.  as one candidate after another has risen to the top only to implode - culminating in Herman Cain's decision yesterday to suspend his camaign - the race is narrowing into a tussle between two old-timers: Newt v Mitt.  Many of the 400 people attending the Polk County dinner said the 68-year-old Gingrich had not even crossed their mind until the last couple of weeks. They had gone through flings with Congresswoman Michele Bachmann until she said one crazy thing too many; Rick Perry, the governor of Texas, until a series of what americans call "flubs" in debates (last week he even got the voting age wrong); then Cain, the former pizza executive and Baptist minister, until a bevy of women alleged sexual harassment.  "I liked Perry until I just didn't see him debating well, then Cain, well ..." said Pattie Johnson, a nurse. "With Newt, the more I hear, the more I like. He's rising to the top like cream and I think he'll stay there."  For a thrice-married man with a reputation as a philanderer, it is startling that Gingrich should be the main beneficiary of Cain's shenanigans. "Newt is just the latest in a series of primal screams the party's going through," shrugged an aide to Romney. "Given the half-life of these surges, the question is can he last another 30 days?" Others disagree. "We're past the flavour of the month phase," said Kevin McLaughlin, chairman of the Polk County Republicans. "The mood of people after listening to him was of unbridled enthusiasm."  There is little love lost between the professorial know-all Newt and the suave businessman Romney.  David Corn, of the liberal magazine Mother Jones, compared it to a high school brawl. "You have the big male on campus, the student body president who looks good - Romney. and then you have Gingrich, the snarky nerdy guy who knows how to get under the other fellow's skin."  Round one will be the Iowa caucuses on January 3 when one of america's smallest states will gather in homes, churches or community centres to listen to candidates' representatives and cast their ballots.  With polls showing as many as two-thirds of the state's 600,000 registered Republicans undecided, it presents an unexpected opportunity for Gingrich and Romney, neither of whom had a campaign office there until last week "Iowa is going to be ground zero for national politics for the next four weeks because there is tremendous uncertainty even who will be in the top three," said Matt Strawn, chairman of the Iowa Republicans.  "My advice to all candidates is spend as much time here as possible."  Four years ago, Romney campaigned hard in Iowa, devoting much time and $10m, only to lose heavily to Mike Huckabee, another Baptist minister.  Burnt by that experience, he has played down Iowa this time, convinced he cannot win when 60% of the voters are evangelical Christians, many of whom would never vote for a Mormon. Instead, he has focused his efforts on more liberal New Hampshire, which votes a week later.  He has made only five visits to Iowa in this campaign. However he did not give up altogether, said Doug Gross who chaired his campaign last time. "He's playing rope-a-dope - acting like he didn't care while they've been mounting a major effort," he said. "Iowa is a big deal. If he wins here he could seal the nomination.  I'd be advising him to go all out in Iowa now."  One advantage is the fact that with so many social conservatives in the field, the evangelists have been unable to agree on a candidate.  "My own team can't agree among themselves, let alone all the groups," said Bob Vander Plaats, head of Family Leader, a conservative organisation. "The dilemma we have is if we in the conservative base don't coalesce around one candidate, our voice will be fragmented and a Mitt Romney skates to victory."  Last week Romney broadcast his first Iowa television commercials and opened a large campaign office. The Sunday Times found it deserted apart from two men at desks.  Some Romney advisers fear that if he steps up campaigning in Iowa, he will raise expectations and his campaign will be damaged if he loses again.  "Our focus is on the national," said one. "There's a path to the nomination for Romney that doesn't involve Iowa. Whereas Gingrich must win here as he doesn't have the organisation we have nationally."  Compare 