The pictures below are from the 2008 Democratic Iowa Presidential Caucus in Monticello, Iowa, precinct 4. This is a fascinating thing to see, and it's a pity not everyone can attend one.
First we have a shot of the Hillary Clinton supporters as the initial "organization" takes place: the supporters of each candidate move to a different part of the room and count heads.
Here, we see the supporters of Joe Biden delivering their count. In a district sending four or more delegates to the state convention (this district will send six), a candidate needs the support of 15% of voters to be "viable" and get at least one delegate; in this precinct, where 67 voters showed up (50% more than in 2004!), that meant 11 voters, and the unfortunate Biden backers had only five--so no delegates for Biden (which was a pity--he was one of my two favorite candidates).
Fortunately, votes for unpopular candidates aren't wasted: after the first count, there's a "re-organization" into new groups, as members of the viable groups try to convince the the voters of smaller groups to join them, or smaller groups coalesce into viable ones. In this precinct, there were only eight voters for all of the "second-tier" candidates put together (five for Biden, two for Dodd, and one for Richardson--my other favorite), plus one uncommitted voter (the caucus chair was also nominally uncomitted in the first round, to give the appearance of fairness, but in fact she was a John Edwards supporter). Here are the Edwards backers during the re-organization.
And next we have the supporters of Hillary Clinton and Barack Obama....
In these pictures, a group of Clinton supporters, and probably one or two supporters of Barack Obama, woo the Joe Biden group (joined briefly by the lone Richardson voter), while an Obama backer works on the undecided voter on the other side of the room. Note the guy in glasses on the left: he was a Clinton staffer, not an Iowa voter, and therefore wasn't supposed to talk during the caucus. Clinton staffers did this in both of the precincts observed by groups of students and professors from our college (two of the students are seen on the right-hand side of the left picture).
Here the chair laughs it up with a group of fellow Edwards supporters (though I think the woman on the far right is a Clintonite asking a question), while the Clinton camp plans its next move in the middle of the room.
In the meantime, the push to win over the Biden hold-outs continues, with advocates of Edwards, Clinton, and Obama all working at the same time.
Finally, all of the supporters of non-viable groups have joined one of the larger camps. In the pictures below, we see the newly enlarged Clinton faction, which conducts a new head count in the right picture; of the three people standing in the middle of the left picture, the center one originally supported Biden, while the one on the right supported Richardson. The re-organized voters went mostly to Obama and Clinton (four to each), but didn't add enough to Clinton's and Obama's totals for either candidate to pick up another delegate, though the addition of the chair and the uncommitted voter did give Edwards one more than he needed to do so.
The final count was 26 for Obama, 23 for Clinton, and 18 for Edwards. Since there were only six delegates to allocate, after rounding off, each of the top three candidates got two delegates.
With everyone now a member of a viable group, the vote was final, and the chair duly reported the results.