Danielle McLaughlin

One week from Tuesday, the Iowa caucuses will begin. They signal the official beginning of the Democrats’ 2020 primary election race, and are a complex and quirky process from which the very first actual ‘‘presidential’’ votes emanate.

Their first-in-nation status creates important momentum for candidates who do well there, particularly when there is a large field.

How to make sense of what they are, and what they mean?

A caucus is much divorced from the typical way a vote is cast: on a machine at a local polling station.

Caucuses are community-based events, where hundreds of people show up (often in school gymnasiums and community halls) to quite literally ‘‘vote with their feet’’.

Held for decades now at the beginning of the presidential election year, voters convene on a frigidly cold winter night to participate in what the Washington Post calls ‘‘the nation’s most consequential game of musical chairs’’.

Simply put, caucus-goers first group themselves physically in the room according to the candidate they support. Based on the head count, any candidate with at least 15 per cent of the votes in the room is deemed ‘‘viable’’.

Supporters of non-viable candidates who do not meet that threshold have a variety of options. They can give up and go home or, more helpfully, they can either add their support to a viable candidate; help a non-viable candidate get to 15 per cent; or try to convince other supporters of non-viable candidates to support their own, pushing him or her into the ‘‘viable’’ category.

Once the caucus is left with only viable candidates, they are each allocated ‘‘state delegate equivalents’’ based on their head count support.

Finally, the total of delegates from every caucus held across the state – one for each of Iowa’s 1681 precincts – is tallied, and represents the results for the state.

Iowa is the first state in the presidential primaries for reasons related to the 1968 Democratic National Convention, which was held in Chicago. The convention holds a dark position in US political history on account of the violent protests that erupted around it. Tens of thousands protested the Vietnam War, railing against the political class.

The notion of a ‘‘caucus’’ – a community-based method of selecting a party’s presidential nominee – already existed in Iowa. Democrats decided to hold them in other states, too.

In Iowa, in order to make the existing caucus system more inclusive, Democrats decided to create a longer lead time for notice to voters.

Between that, and the fact that more hotel rooms were available in the state capital in January rather than at the height of summer, the Iowa caucuses moved in 1972 to the beginning of the year. And there they have stayed.

For all the fuss, Iowans are pretty terrible at picking the president. On the Republican side, only one non-incumbent nominee (George W Bush) has ever won the Iowa caucuses. On the Democratic side, there are only two – Jimmy Carter and Barack Obama.

This is not to say that Iowa doesn’t matter. It can convince later primary voters in other states that more obscure candidates have the potential to win. Carter’s win in 1976, for example, proved that a focus on Iowa could launch an otherwise little-known former governor of Georgia on to the national stage.

Similarly, Obama in 2008 spent millions in Iowa organising and convincing voters who had never attended a caucus to participate in the state’s community voting system. It worked, and he beat seven better-known candidates, including Hillary Clinton, to win the first primary election of the year.

Traditionally, the Iowa caucuses don’t formally announce a ‘‘winner’’, releasing only the delegate count (which undoubtedly reflects who won). This year, a rules change – urged by Bernie Sanders after the 2016 caucuses – means that the organisers will announce two additional numbers. First, the vote tally at the beginning of the night, where all candidates are still included; and second, a vote tally at the end of the night, once the non-viable candidates have been abandoned.

This is likely to cause a mess of messaging. Candidates who did poorly by delegate count will raise raw vote counts as indicative of voter support. A ‘‘win’’ by other means.

Iowa might not be the greatest harbinger of the identity of the next US president. But it may be a harbinger for the nature of the Democrats’ 2020 race.

Given the size of the field and the tensions within the progressive and moderate wings of the Democratic Party, more ‘‘wins’’ in Iowa (real or imagined) could mean more candidates battling further through the primary season.

In fact, Democrats may face multiple candidates vying against each other in a contested convention when they convene in Milwaukee in July to pick the presidential nominee.

If this is so, so be it. But Democrats ought to be mindful of Ronald Reagan’s so-called ‘‘Eleventh Commandment’’, in which he professed during his 1966 bid for governor of California to never personally attack his Republican rivals. Reagan knew that those attacks would eventually be used by the other side to harm his party’s nominee.

It will be no different in 2020.

Danielle McLaughlin is the Sunday Star-Times’ US correspondent. She is a lawyer, author, and political and legal commentator, appearing frequently on US and New Zealand TV and radio. She is also an ambassador for #ChampionWomen, which aims to encourage respectful, diverse, and thoughtful conversations. Follow Danielle on Twitter at @MsDMcLaughlin.