For those unaware, a caucus is totally unlike a primary.
In a primary election, you show up to a polling place, you cast your ballot for your chosen candidate, the ballots get counted, and whoever wins is whoever wins. On to the next state!
"The Republican caucuses will convene statewide at 7 p.m. local time (8 p.m. EST), and begin with the election of a caucus chair and secretary. Only registered Republicans may participate in the caucuses and only in their designated home precincts. However, Iowans may register or change their party affiliation on caucus day. Voters must turn 18 by the November general election in order to participate."
"There is no walking around the caucus room to form candidate preference groups. That voting method was a feature of Democratic caucuses from 1972 to 2020 but is no longer in use by either party in 2024."
"The binding presidential vote functions essentially like a party-run primary, only with very limited polling hours and no accommodation for absentee voting, except for a tiny handful of overseas and military voters. There are speeches on behalf of various candidates before the voting and a variety of party business after the vote. Individual caucus chairs are allowed to exercise some discretion in how to conduct the vote, but the voting is done by secret ballot and there is no set list of candidates. Voters must be given the option to vote for any candidate they choose. In the past, some caucus sites have pre-printed the names of major candidates and provided a write-in option, but typically, voters vote by writing the name of a candidate on a blank slip of paper."
The "limited polling hours" is key here, because if you decide to step out for a smoke, or to hit the bathroom, or grab a sandwich when the vote is called, you might not get counted at all.
In previous years this has led to accusations of under-counts, over-counts, and all other manner of shenanigans.
Here's the history of the past few Iowa Caucuses and how it related to the general election:
2016:
Ted Cruz - 8 Delegates, 51,666 votes
Donald Trump - 7 / 45,429
Marco Rubio - 7 / 43,228
Ben Carson - 3 / 17,394
Rand Paul - 1 / 8,481
Jeb Bush - 1 / 5,238
Carly Fiorina - 1 / 3,485
John Kasich - 1 / 3,474
Mike Huckabee - 1 / 3,345
2020:
Donald Trump - 39 Delegates, 31,421 votes
Bill Weld - 1 / 425
There are a bunch of different plans organized around getting people to the polls, particularly the elderly. But, yeah, it's an added layer of complication.
"Unlike their Republican counterparts, the Iowa Democratic Party will not host an in-person presidential preference contest, opting instead for mail-in ballots listing incumbent President Joe Biden, Minnesota Rep. Dean Phillips, Marianne Williamson, and an option for "uncommitted."
The party started accepting requests for these cards via a Google form on the party's website and by mail on Nov. 1, 2023. And while they will start to be mailed out to voters on Jan. 12, they will not be accepted in person at the caucuses.
All cards must be postmarked by March 5, a date when more than a dozen other states hold their primaries, otherwise known as Super Tuesday."