Iowa voters kicked off the long process of choosing the Democratic and Republican party’s presidential nominees Monday, ahead of the November election.

Following a shock delay, the first partial results were released on Tuesday and continued to trickle in through Wednesday and Thursday. The Associated Press said it was unable to declare a winner Thursday evening.

*Election results source: Associated Press

What is a caucus and how is it different to a primary?

Most US states hold primary elections, in which voters go to a polling place, mail in their ballots or otherwise vote remotely. But a handful of states hold caucuses – complicated, hours-long meetings, which continue until one candidate emerges as victor. And the process is different for Democrats and Republicans.

How do the Democratic caucuses work and why are they important?

Iowans aged 18 and over who are registered with the party will gather in caucus venues such as school gyms and churches in their designated precinct. They start voting publicly at 7pm CT (8pm ET) by splitting into groups based on their preferred candidate.



Voters have to go and stand in the area where their candidate is represented. So Joe Biden supporters would be in one corner, Elizabeth Warren in another and Bernie Sanders supporters in another. Everyone is tallied.

If a particular candidate does not attract 15% of total voters present, they are taken off the ballot, and their voters are free to throw their weight behind another candidate.



Once voting is over at a caucus site, the support for viable candidates (those with more than 15% of the votes) is translated into a number of “state delegate equivalents”. That result is used to calculate the number of national delegates each candidate receives. National delegates eventually choose the nominee at the Democratic convention in July.



On the night of the caucuses, the candidate with the most SDEs is considered the winner.

How do the Republican caucuses work?

With all the attention being paid to the Democratic side, it is easy to forget that there is a Republican primary happening, too.



Trump is facing challenges from the former Massachusetts governor Bill Weld and former US representative Joe Walsh, but it’s extremely unlikely that they, or the others (according to the Federal Election Commission, 153 people are running for president as Republicans) will win against the president.

In the Iowa Republican caucus, people still have to physically show up at a location. They then cast a straightforward vote, secretly. The votes are tallied up, and the delegates are dished out in the same manner.

In the Republican caucuses, there is no 15% threshold, meaning candidates with relatively little support could still pick up delegates.