Iowa caucuses: Bernie Sanders predicts voters will snub Hillary Clinton - weather permitting

Mr Sanders said he is on the cusp of 'one of the biggest political upsets in modern history'

A supporter wears a T-shirt featuring Democratic presidential candidate Bernie Sanders (Getty)

Bernie Sanders has boldly predicted that he is on the cusp of delivering “one of the biggest political upsets in modern history” by defeating Hillary Clinton, once the overwhelming favourite, in the Iowa caucuses on 1 February. But, with grim weather on the way, he conceded it will depend on his supporters actually showing up.

It may be a cliff-hanger night for both parties. As the results flow in, America will have a first indication of whether all the forecasts of a radical up-ending of the political order by an angry electorate may really come to pass. For Republicans, the excitement will be about Donald Trump and his ability to seal the deal.

The weather forecast was also in play. The promise of rain and snow for most of the state this evening could deter some from attending their caucus meetings, a prospect that spells danger for both the insurgent candidates, Mr Sanders and Mr Trump, for whom very high turnouts are expected to be crucial.

Ms Clinton goes into voting day with the thinnest of leads, according to the final, and most respected, poll released late on 30 January by Bloomberg and the Des Moines Register. She was at 45 per cent support vs 42 per cent for the senator from Vermont, within the margin of error. A loss to Mr Sanders, who is far ahead of her in New Hampshire which votes next, could seriously harm her.

“I think I’ve been subjected ... to years of scrutiny and I’m still standing,” Ms Clinton, former Secretary of State and one-time US senator told ABC News. “I feel vetted. I feel ready. I feel strong and I think I’m the best person to be the nominee and to defeat whoever they nominate in November.”

The ground games of the campaigns on 1 February will be key. In spite of his advanced age at 74, Mr Sanders has drawn overwhelming support from younger Democrats but he needs them to vote. A Saturday night rally in Iowa City, home of the University of Iowa, with the popular band Vampire Weekend, drew 4,000 people. Pundits say young people “come out for rallies, but you know what, they’re not going to come out to participate in the caucus”, he told the crowd. It roared back. “Yeah we are!”

“People are really enthusiastic and if people come out to vote, I think you’re going to look at one of the biggest political upsets in the modern history of our country,” he told CNN.

At one of his final rallies, in Dubuque, Mr Trump, who leads Senator Ted Cruz of Texas by 28 per cent to 23 per cent with Senator Marco Rubio showing third at 15 per cent, also referred to the turnout. “You’re from Iowa,” he bellowed. “Are you afraid of snow?”

The dynamics of the Republican contest also appeared fluid. The same poll showed that in the event of a higher-than-expected turnout of evangelical and born-again Christians, Mr Trump and Mr Cruz would draw almost level at 26 per cent and 25 per cent. There were also signs that Mr Rubio was picking up support, however, which could syphon votes mostly from Mr Cruz.

On ABC News, Mr Trump prudently attempted to lower expectations. “I don’t have to win” Iowa, he suggested, pointing to the wide polling leads he has in the next states that will vote for a nominee. Yet, while the state offers only a minuscule fraction of the delegates who will eventually decide who the nominee will be, the outcome has a disproportionate impact on the perception of a candidate’s viability.

Did Mr Trump always imagine winning here? “The truth is, no, I didn’t,” he said. “I’m somebody that knows how to win. I close the deal. But I never thought I’d have 24-point leads in different states.”