The Obama re-election machine has mocked Mitt Romney as "the 25 per cent man", seizing on the Republican favourite's inconclusive win in the Iowa caucuses to relish a prolonged nominating race.
President Barack Obama's Chicago-based campaign team seemed delighted that Romney failed to pull off the kind of big win that could have put an effective lock on the Republican nomination in Iowa's curtain-raising contest.
Romney now faces weeks of attacks from his right, on his record and his character, that could leave a negative impression in the minds of voters should he emerge as expected, as Obama's general election opponent in November.
Romney won the Iowa caucuses, the first event in a nationwide nominating marathon, over outsider Rick Santorum on Tuesday by a miniscule eight votes, capturing 24.6 per cent of the total turnout.
But he fell short of expectations of victory that he had fanned himself in a result which revived debate over his appeal to the Republican conservative base and scotched expectations he could quickly unite the party around him.
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"I think it is very possible that this race could go on for a while," David Axelrod, Obama's political guru, told reporters. "He is still the 25 per cent man and until he proves that he is not, I don't think we can close this nominating process."
Although he poured millions of dollars into Iowa in a late push for victory, Romney actually got a slightly smaller share of the vote in 2012 caucuses than he did when he came in second during his unsuccessful 2008 presidential run.
But this year's caucuses may have still aided his campaign, after denting Rick Perry and Newt Gingrich, two candidates once thought capable of challenging him on a national stage.
Although Santorum ran strongly among Christian conservatives in Iowa, he spent months in the state to the detriment of subsequent battlegrounds.
He also lacks either the national infrastructure or funding he would need to take on Romney.
The next Republican contest comes next Tuesday in the New Hampshire primary where Romney is heavily favoured, but Obama's team, in a spot of advance spin, said anything short of a thumping win would dismay the Romney campaign.
A Suffolk University tracking poll on Wednesday showed Romney leading in New Hampshire with 43 per cent of the vote, with libertarian conservative Ron Paul on 14 per cent, Gingrich on nine per cent and former US ambassador to China Jon Huntsman on seven per cent.
Santorum, seeking momentum after Iowa, was on six per cent. Obama campaign manager Jim Messina meanwhile said that the Republican caucuses had given the Obama team a chance to fire up its own grassroots network, which could be crucial as Iowa will be a key battleground in November.
He said that 25,000 people turned out to support Obama in uncontested Democratic caucuses in Iowa, the state where the campaign first built the insurgent network that eventually powered Obama to the White House. "It proved that organisation still matters and it gave you a look at a microcosm of what we are building in states across the country," said Messina.
Obama now has eight field offices in the state and the campaign has carried out 4,500 training sessions for voters and 440,000 calls to voters since April, the campaign said.
While it is responding to Republican attacks, the campaign is seeking to build countrywide political machinery to provide Obama with multiple routes to the 270 electoral votes needed for victory in November's election.
Romney, while seeking to secure the nomination, has framed himself as the best placed Republican to take on Obama, and has conducted a savage examination of the president's economic policies.
In a new radio advertisement airing in New Hampshire on Wednesday, he took aim at the lofty expectations that accompanied Obama's election in 2008, and the current state of America.
"Four years ago, Barack Obama promised to repair the country and world. Four years later, it is clear that President Obama's policies have been failures," Romney said in the ad. "It is time for this pessimistic president to step aside so American optimism can help rebuild our country and economy."
