Caucuses are only the first stage in key voting states’ selection process and provide a litmus test for which party candidates could fare well in the primaries

Countdown to Iowa: a caucus guide for what to know about America's first vote

The Iowa caucuses are a unique political institution that play a crucial role in the American primary process. However, they aren’t particularly intuitive to understand or follow. (Even though we’ll be live-blogging them all day and night at the Guardian from here across the first-in-the-nation voting state.)

What time do the caucuses start?



The caucuses start at 7pm local time on Monday, but campaigns encourage their supporters to show up half an hour early.



How do the caucuses unfold?

Very different rules govern the Democratic and Republican caucuses:

Republicans have a relatively straightforward process, in which they cast secret ballots in their precinct caucuses – church halls, school buildings.

By contrast, Democrats vote publicly in a two-stage election where candidates must get support of 15% of caucus-goers in each individual precinct to be viable. If they fall below that threshold, their voters need to choose another candidate or go home. After that redistribution, votes are counted and from those totals, delegates are assigned.



Lessons from Iowa: real caucus victory comes from beating expectations Read more

Can unregistered voters take part?

Any Iowan who will be over the age of 18 at the time of the presidential election (on 8 November) can participate. Attendees can register on the night at the caucuses and can switch their party affiliation there as well. This means a Democrat can go to the Republican caucuses and vice versa. Four years ago, 121,503 people showed up to the 2012 Republican caucuses. Democrats have traditionally had higher turnout and, in their last competitive caucus in 2008, 239,872 people attended.

What happens then?

The caucuses are political party-run processes with no state involvement, so the reporting of results doesn’t happen through state election officials. Instead, local volunteers at each caucus location across Iowa’s 99 counties report them. This means there can potentially be many hiccups:

For Republicans, the ballots are tallied and counted at each caucus site and reported to the state party.

Under the Democratic system, only the actual number of delegates pledged to each candidate is reported and not any actual vote counts.

Barring reporting issues, a clear idea of the results should emerge by around 9.30pm local time.



How are delegates decided?

American presidential primaries are all about electing delegates to the party conventions which are staged over the summer and where nominees to run for president will formally be chosen. The caucuses don’t formally select those delegates. Instead, they represent the first stage in Iowa’s multi-part selection process, but campaigns and the media will be able to extrapolate how many delegates they will receive based on Monday’s result.

After Iowa, three more states – New Hampshire, South Carolina and Nevada – will hold standalone, early contests in February. Then, starting 1 March, the calendar starts to fill up, beginning with “Super Tuesday”, when 12 states will hold nominating contests. The primary election will then continue until 7 June, when the final six states, including California, hold their elections.

Where will the candidates be on the night?

How the Iowa caucuses work: a confusing election process explained Read more

Most candidates will be holding election night parties in and around the state capitol of Des Moines on Monday night to watch the results. Some are already in New Hampshire, though. Ohio governor John Kasich has long since written off Iowa to campaign almost exclusively in the Granite state and former Florida governor Jeb Bush will fly to New Hampshire on Monday after a last minute campaign swing through Iowa. Both candidates are currently polling at 2% in Iowa.

What happens next?

Most of the candidates will go off to New Hampshire with charter planes expected to depart Des Moines for Manchester sometime after midnight on Tuesday morning. However, one or two Republican candidates may try to skip New Hampshire to shore up their campaigns in South Carolina, which holds the third Republican primary this year, and it’s likely that at least one candidate will end their campaign after Iowa.



• This article was amended on 4 February 2016 to clarify the answer to “Can unregistered voters take part?” An earlier version said “Any Iowan over the age of 18 can participate”.