Any registered voter can participate in a caucus. A voter attends the caucus for their district/township. Each voter is given one ballot, and the ballots are then collected at a certain point in the caucus. Ballots are counted and reported to the State Party. It’s a non-binding count of who people are leaning towards for President. Other party business is also conducted at the caucus, such as nominating delegates, party committee chairmen, etc.
http://en.wikipedia.org/wiki/Iowa_caucus
Ah, thank you very much. Another question, if I may:
“Each voter is given one ballot, and the ballots are then collected at a certain point in the caucus.”
Is this why the angry, rowdy supporters do well in caucuses? Is it because they try and drive out everyone else out before the ballots are passed out, until only they remain?
That link doesn’t quite fit with what I remember. I have never voted in a democrat caucus. But I’m sure I remember dividing up into groups and electing a spokesperson. I remember one guy in my group said “I’ve done this before and it usually works best if a preacher or minister is our spokesperson. Who here is a preacher?”.