The Iowa caucus is the first test for US Democratic presidential candidates. The results are hard to predict for two reasons: voters’ indecision, and a caucus system that means they may have to go with their second choice.
The Midwestern state of Iowa is home to some 3 million people, yet it has outsized importance because its caucus comes first in the presidential primary cycle.
An individual caucus is essentially a small local meeting in a school gym or community centre - known as a precinct - where neighbours and strangers show their support for a particular candidate by standing in groups and trying to persuade others to join them.
There are two rounds of voting in a caucus. In the first, the people attending gather in spaces that are designated for their preferred candidates. Any candidate who attracts 15 percent of the people present in the room is considered viable, and goes on to the next round.
People supporting candidates who do not meet the 15 percent threshold have four options: They can support a viable candidate, join with supporters of another non-viable candidate to boost them up to 15 percent, or try to woo supporters of other non-viable candidates over to their camp. Or they can simply go home.
Carol George is a precinct team member for former South Bend, Indiana Mayor Pete Buttigieg. “I was pro-Warren at the start but now I am for Buttigieg,” George said. She explains that if he does not get the 15 percent he needs in her precinct, she will go to Massachusetts Senator Elizabeth Warren as her second choice.
Warren’s programme is in many ways similar to Vermont Senator Bernie Sanders’s, but that does not mean her supporters would pick Sanders as their second choice. Many of them told FRANCE 24 that they would prefer to support Buttigieg or Minnesota Senator Amy Klobuchar in a round two scenario.
That is the case for Mike Kaldenberg, who works in IT in Des Moines, Iowa’s capital. He is supporting Warren because he is “ready for a lady president” but would opt for Pete Buttigieg if Warren does not get a big enough group in round one in his precinct because, “[Buttigieg’s] a former military person as well. I served 20 years in the Air Force. I trust his knowledge too.”
The early date of the Iowa caucuses gives voters in the Hawkeye state a special responsibility.
"You are the most important people to America's future. For the next 24 hours plus, the world is watching what we do in the great state of Iowa," said the state’s former Governor Tom Vilsack at former vice president Joe Biden’s final campaign rally in Des Moines ahead of the vote.
Iowa has 41 state delegates up for grabs in the contest. The winner gets a lot of media attention, but candidates do not have to come in first to gain momentum for the rest of the primaries. And the caucuses don’t always pick the eventual nominee – then Arkansas governor Bill Clinton finished fourth in 1992, the year he won the presidency – but they did in 2008, when voters gave Barack Obama victory.
There are 11 Democratic candidates still in the race to be their party’s nominee to face President Donald Trump in November. Sanders and Biden are leading the pack, but Buttigieg, Warren and Klobuchar could get a boost even if they don’t win.
Sanders spent the weekend before the caucus encouraging people to attend.
“If the voter turnout is low, we are going to lose,” he said at a rally in on Saturday. “If people across this state are prepared to come out, not just to defeat Trump but to transform this country; if working people and young people and all people who believe in justice – if they come out in large numbers, we’re going to win this caucus.”
Sanders is counting on a victory on Monday night, but if he cannot win over Warren supporters later on in the electoral cycle, he may struggle to stay ahead in the race.