After a year of intense campaigning, Iowa votes tonight in the first contests to choose the Republican and Democratic presidential nominees, with polls showing both races too close to call, writes Denis Stauntonin Des Moines, Iowa
As the candidates made final appeals to voters in television adverts and at rallies throughout the state, campaign workers prepared for the biggest get out the vote operation Iowa has ever seen.
"Forget about polls, they don't matter any more. It's now all about your ground game," Hillary Clinton's campaign chairman Terry McAuliffe told The Irish Times.
"How do you get your voters to come out at 6.30 at night, to be in that room by 7 o'clock and get them to stand there and be counted for Hillary Clinton? So I tell everybody, forget all the polls, forget the television ads, it doesn't matter any more. It's showtime."
The Clinton campaign is setting up creches throughout Iowa to help women voters - a key group for the former first lady - to attend the caucuses and providing 5,000 cars to carry voters to the caucus venues. The campaign has identified tens of thousands of supporters it believes can be relied upon to deliver Ms Clinton a victory that could put her on an unstoppable course for the Democratic nomination.
The final poll from the Des Moines Register, Iowa's most influential newspaper, gives Barack Obama a seven-point lead over Ms Clinton, mainly on account of Independent voters, who the poll expects to make up 40 per cent of Democratic caucus-goers, with Republicans who switch parties making up a further 5 per cent.
Rival campaigns have cast doubt on the poll but attendance at Mr Obama's events in recent days has swollen from an average of 300-500 to more than 1,000, and his campaign is confident that enough Independents will caucus tonight to push him into the lead.
John Edwards is depending on voters who have caucused before, a more reliable cohort than any other, and on trade unionists who are energised by his promise to confront corporate power.
Despite his confidence in Ms Clinton's ground operation, Mr McAuliffe talked down the importance of winning Iowa, insisting that Ms Clinton can afford to lose the state and still win the nomination.
"I think it's very important for John Edwards. I think he's staked his entire campaign on winning Iowa. I think Barack Obama has put a lot of emphasis here - he's got to show well. Listen, we want to do well in that first contest but we look at 27 states where we have to play and we're doing great in those. We're up in New Hampshire, we're up 30 points in Nevada, we're up in South Carolina, we're up in 21 of 23 states on February 5th.
"A lot can change," added Mr McAuliffe. "We feel very good but no one state for us, because of who Hillary is, is going to determine how we go or don't go," he said.
The Republican race is between former Massachusetts governor Mitt Romney and former Arkansas governor Mike Huckabee, with Senator John McCain and former senator Fred Thompson battling for third place.
Mr Romney, who has outspent Mr Huckabee by a factor of almost 20, has the best organisation in Iowa but the former Arkansas governor is hoping that evangelical Christians, who account for 40 per cent of Iowa Republicans, will turn out in unprecedented numbers tonight.
To win Iowa, Mr Huckabee needs the support of voters like Richard Nation, a retired factory worker from Norwalk, who is drawn to the former Baptist minister's stance on social issues.
"I like the fact that he sees himself as a servant of the people and that he comes from a biblical perspective in his values. I'll go out and caucus for that," Mr Nation said.