Today is the first major milestone in the race to the White House. The Iowa Caucus will be held tonight.
To help clear up the confusion about the caucus, here's a little primer on Iowa's unique system.
The caucus differs from a primary, in that instead of all-day voting similar to a general election (like in New Hampshire's primary next Tuesday), the Iowa caucus are composed of a bunch of meetings held across the state.
Starting at 6:30 PM CT for the Democrats, 7PM for the Republicans, Iowans have to show up at a precinct, regardless of the weather, and each caucus goer stands up at the meeting and declares their support for a presidential candidate.
They then group themselves by who they support and take a head count. It is determined before the caucus how many delegates will come out of that precinct, and depending on the number of voters in the room, divided by number of delegates designated, each presidential candidate gets one, or two, three (or so forth) delegates.
If after the first head count a presidential candidate does not have enough votes for even one delegate, his supporters are free to move to another candidate. This is where the fun starts. The other camps invite these free voters to join their candidate, hoping to get enough additional votes to qualify for yet another delegate.
After this reshuffle, they take another vote. In the end, they will report out something like this: 3 delegates for Candidate A, 2 for Candidate b and 1 for Candidate C, and none for the rest.
Here's a clever little video by the John Edwards campaign on how the caucus works: