Take
exit 64 off the interstate highway between Des Moines, Iowa, and Omaha, Nebraska, and the asphalt quickly gives way to a dirt track through rolling cornfields that stretch as far as the eye can see.
Five miles north, the track reaches Exira, a town of 800 people, where most vehicles are
mud-splattered 4x4s and the only visible industry is farming. It may seem like an unlikely place to hold a presidential campaign rally but in Iowa, no town is too small to merit the attention of White House hopefuls.
"You are the
guardians of what kind of president we will have," says John Edwards, the Democratic contender, addressing 200 people in the Exira High School gymnasium. "The rest of the country will see 30-second
sound bites. You have the opportunity to see us stand in front of you and answer hard questions."
Every four years, the road to the White House runs through Exira and towns like it across Iowa, because of the state's
crucial role in the presidential nomination process. Iowa traditionally holds the first of the state contests that
determine each party's presidential nominee, setting the tone for those that follow days later in New Hampshire, South Carolina and elsewhere.
For Mr Edwards, victory in Iowa in early January - or possibly a strong second-placed finish - is essential if he is to have any chance of beating Hillary Clinton and Barack Obama to the Democratic nomination. National opinion polls make the race look like a
foregone conclusion, with Mrs Clinton supported by nearly half of likely Democratic voters, compared with 21 per cent for Mr Obama and 12 per cent for Mr Edwards. But the contest is much closer in Iowa, where Mrs Clinton is backed by about 29 per cent of Democrats, compared with 24 per cent for Mr Obama and 21 per cent for Mr Edwards.
In Exira, Mr Edwards had an answer for those who believe Mrs Clinton is unbeatable. "They said the same thing about Howard Dean," he said, referring to the 2004 Democratic candidate who entered Iowa as the
runaway frontrunner but left the state with his campaign in ruins after finishing third.
Experts believe a similar fate is less likely to
befall Mrs Clinton because her campaign is vastly stronger and more disciplined than Mr Dean's maverick operation and her poll lead in Iowa is expanding. Mr Edwards, by contrast, has appeared to fade in Iowa, having led the polls for much of this year before slipping to third place recently.
But David Redlawsk, political scientist at the University of Iowa, says the situation remains "extremely fluid", with all three main candidates still
in contention. "A lot of
caucus-goers do not make their decision until the last couple of weeks," he says, referring to Iowa's unique caucus voting system.
Mr Edwards has the benefit of experience in Iowa, having finished a surprise second in the 2004 caucuses, behind John Kerry, whom he eventually joined on the Democratic ticket as vice-presidential candidate.
He has often appeared to set the agenda in the Democratic race this year,
tapping into the growing sense of economic insecurity among middle-class Americans with his promise of greater protection for US jobs against the forces of globalisation. But
he struggled to exploit his policy leadership because of the fundraising advantage held by Mrs Clinton and Mr Obama, who have both raised more than twice as much as the former North Carolina senator.
Iowa offers Mr Edwards his best opportunity to
level the playing field because the personal, grassroots nature of campaigning in the largely rural state reduces the influence of money. Iowans pride themselves on their deep engagement in the nominating process, with a recent poll showing that a quarter of likely caucus-goers have already met at least one presidential candidate.
Mr Edwards has the advantage of being the leading white male candidate in a state that is 96 per cent white and has never elected a woman to Congress. But he told Iowans it was his values that made him the best candidate, not his race or
gender. "I worry sometimes that presidential candidates think of these rural counties as places they fly over when they go from New York to LA," he said. "Well, for me, it's where I'm from."