After months of town hall meeting attendances, talk show appearances, and fierce debates exchanges in which die Democratic candidates have made their pitch, the 2020 election year is finally about to start.

On February 3rd, the Iowa caucus takes place, and the national favorites Bernie Sanders and Joe Biden have been able to set themselves apart from the rest of the field in the Hawkeye State. According to a Real Clear Politics poll, Sanders leads Iowa with 25 percent, ahead of Biden, who is at 22 percent.

The current polling, however, just as in most regular elections, does not always indicate the subsequent result, particularly in Iowa, where currently, only between 31-40 percent of voters know whom they will vote for. Consequently, the other candidates, such as Elizabeth Warren, Pete Buttigieg, or Andrew Yang, thus still have the chance to make a name for themselves till the caucus night commences.

The sheer number of undecided voters in combination with the format in which voting will be conducted is one of the reasons why all eyes will be on Iowa on Monday. Iowa is one of only four states in the US that decides the results of its election through caucuses, while the rest of the nation relies on primaries.

The latter is the basic principle of voting for one’s preferred candidate in the ballot box, similar to most west-European countries. A caucus, however, is not only conducted differently but is significantly more complicated than a primary – at least the Democratic caucuses.

On election night, voters caucus in their local voting precinct, most often in a public forum like a library or a high school gym. Here a voter will spend several hours on the voting process, as, during the evening, it is not uncommon for a voter to debate and argue about candidates during ballot rounds. Under Iowa’s unique caucus rules, voters’ second choices could be decisive, as, if a candidate does not obtain 15 percent support in a local precinct in a ballot round, they are not considered viable.

These votes will not tally, and supporters are encouraged to pick someone else and thus switch allegiances. A field that will be crowded at first will thus, over several hours, narrow down to a single winner in the respective precinct. Whichever candidate wins the most precincts – of which there are 1681- wins the state of Iowa. Due to this procedure, and the time that will often be spent on persuasion and debating, a caucus is a time-consuming event and thus attracts mainly people who have a genuine passion for politics. However, and most importantly, the Iowa caucus can produce real surprises.

The former notwithstanding, Iowa remains a small state and, as such, the number of delegates for the candidates available, amounts to only 1 percent of the delegates vote during the Democratic Convention (52 out of 4700). Moreover, the small, predominantly white, rural, and highly religious state does not represent the rest of the country – which is why the presidential candidate Michael Bloomberg is not even campaigning in Iowa.

However, Iowa is not so much about delegates as it is about testing one’s electability first and foremost and the momentum a win can generate for a candidate second. Since 1992, no Democratic candidate has obtained the party’s nominee who has not won in either Iowa or New Hampshire, although a Democratic winner has only been able to win the presidency twice – Jimmy Carter in 1976 (though he most votes were “uncommitted”) and Obama in 2008.

This year, the Iowa caucus has moreover implemented new rules, which could offer presidential candidates an unprecedented opportunity to advance their results, even if they do not win. In previous years, the Iowa Democratic Party provided only one number: one of the delegates won by each candidate during the night. Now, for the first time, the party will report two more numbers, i.e., which candidate had the most votes at the beginning and end of the night. According to party officials, the new process aims to improve transparency. However, there is a growing feeling of confusion when multiple candidates are given a chance to say that they won the vote.

Sanders and his supporters will likely feel happy about the rule change. After all, it was his supporters, who argue that the previous rules during the 2016 caucus against Hillary Clinton stole the election from Sanders, as Clinton was able to win narrowly.

With the changes, even a second place in Iowa, can and will be sold as a win to the supporters, which sets the tone for subsequent primaries and may ultimately improve the candidates chances, as multiple successful candidates in Iowa could prolong the race for the Democratic nomination – and the struggle for some of them.

However, should either Sanders or Biden prevail in Iowa after all and face a similarly fractured field of rivals in New Hampshire, where they also currently lead in the polls, either one of them will be difficult to beat.