John Edwards enters his rally in Des Moines in an elegant blue suit and tie with his famous $400 haircut glistening under the lights.

But to understand why he has a good chance of winning the Democratic caucuses in Iowa that kick off the nomination process in three days’ time, you need look no farther than his feet – incongruously clad in hiking boots.

His outfit is partly a testament to a campaign in which the slick multi-millionaire Southern lawyer has reinvented himself as an angry populist who rails against Wall Street’s corporate greed, free trade, the Iraq war and Washington lobbyists.

Saturday night’s rally is packed, with chanting trade union activists hanging over balconies carrying signs such as “kickin’ ass for the working class”. Mr Edwards shouts: “Brothers and sisters! Enough is enough! It’s time to stand up!”

And they do, rising to their feet and giving him a huge ovation after he promises: “When I win the Iowa caucus, I will have beaten two celebrity candidates [Hillary Clinton and Barack Obama] who have raised more than $200 million between them.”

But his choice of footwear also symbolises the one big advantage he has over his better-funded rivals: organisation and boots on the ground.

One poll yesterday suggested that he was narrowly ahead in the race, while others confirm that he is locked in a painfully tight three-way contest with Mrs Clinton and Mr Obama.

Four years ago he came second in the caucuses to the eventual Democratic presidential nominee, John Kerry, performing particularly well in rural areas. And ever since President Bush was reelected, he has been nurturing his network of Iowan supporters and refining a message designed for this mid-Western state where voters blame the global economy for farms going bankrupt and factories closing.

Mr Edwards was the first candidate to establish chairmen in all 99 Iowa counties and has captains appointed in virtually every one of the 1,781 precincts where the caucuses will take place in community halls and school gyms on Thursday night.

This arcane system is a test of voters’ dedication, requiring them to turn out on a cold January night, spend up to two hours arguing, and then physically cluster in groups supporting different candidates. There is no secret ballot and the pressure to switch sides – from friends, neighbours, employers or union officials – can be daunting for inexperienced caucus-goers.

Mr Edwards’s officials have good reason to believe that they have the edge in the “ground game” with a network of battle-hardened activists.

His rivals have employed hordes of highly paid advisers and computer-modelling techniques to identify supporters. Mrs Clinton is focusing on bringing middle-aged or elderly women, many of whom are inspired by the idea of a female president, into the process. Hundreds of snow shovels are being distributed to precinct captains so that they can clear the driveways of those worried about going out in bad weather.

But yesterday she embarked on some expectation management, telling a TV interviewer that her campaign could survive a third-place Iowa finish, because history shows “that a lot of people live to fight another day”.

Mr Obama is attracting a different group, including young parents – who are being offered free babysitting on Thursday – and students. But such voters were also supposed to be the key for Howard Dean’s Democratic candidacy in 2004 and they let him down.

The caucus comes in the midst of university holidays – and on the night of a big American Football game – when about a third of students will be staying outside Iowa. Mr Obama has urged them to defy predictions about their unreliability. His aides point out that the holidays may yet help him by spreading the influence of Iowan resident students more evenly across the state rather than just in university towns.

His campaign is staging a series of dress rehearsals for nervous first-time caucus-goers to help them to overcome fears about the process. In one such event at the weekend a dozen supporters were asked to pick between different types of cookies – chocolate, chocolate chip or peanut butter.

The Republican race in Iowa has been simplified by the lack of a whole-hearted effort from two leading candidates, John McCain and Rudy Giuliani, who are concentrating their resources on later contests in New Hampshire and Florida.

Mitt Romney has the best organisation, with more than 100 staff in Iowa. His chief rival will be Mike Huckabee, who has a dozen paid workers and a shoestring campaign that will rely on church and home-school networks to get his Evangelical Christian support out.

Indeed, Eric Woolson, Huckabee’s campaign manager, has none of the eye-bulging intensity that marks out those working for Mr Romney or the Democratic campaigns. Instead, he cheerfully shows off the ugly red ant bites he got on a recent holiday to Costa Rica and ponders the healing powers of different ointments, saying proudly: “This one, I think, is illegal here.”

Millions spent on the television showdown

- Iowans have endured 44,600 political broadcasts from the presidential candidates this year

- The Democratic candidates have spent $23.7 million (£12 million) buying ad time, a threefold rise on the amount the party spent on Iowa in the last election

- Barack Obama has spent the most of the Democratic candidates – $8.3 million – followed by Hillary Clinton ($6.5 million) and John Edwards ($2.7 million)

- Republican candidates have spent $9.5 million, led by Mitt Romney at $6.5 million

- If 150,000 people take part in the Iowan Democratic caucus, advertising spending will be the equivalent of $158 a voter. If 70,000 people take part in the Republican caucus, spending will equal $135 a voter

Sources: The New York Times and Times archives

Latest poll

Democrats

Clinton 31%
Obama 27%
Edwards 24%
Richardson 5%
Biden 5%

Republicans

Huckabee 29%
Romney 28%
McCain 11%
Thompson 8%
Giuliani 8%
Paul 8%

Poll by Zogby. Iowa caucus, poll samples taken Sunday 30th December

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