As I’ve noted before, there’s a Democratic delegate selection rule that requires 15% support in a congressional district for a candidate to receive delegates. However, as the Commissar notes, the caucus procedure isn’t exactly a single-ballot electoral situation, according to Carl Hulse of The New York Times:

The chairman of the caucus determines the “viability” threshold for groups backing each presidential candidates, which in most cases will be 15 percent of the number of people attending. Caucusgoers then have 30 minutes to divide into preference groups for the candidates. If some groups supporting candidates do not reach the 15 percent level, those people then have up to half an hour to realign with other campaigns.

At this stage, the pressure will be on the newly liberated caucusgoers to enlist with another candidate. In a deeper layer of strategy, some participants might even align with a candidate they are not that wild about to cut into the count of those who most threaten their first choice.

At the end of 30 minutes, the preference groups are counted again and the delegates are apportioned by multiplying the number in the preference group by the number of delegates up for grabs in a precinct, then dividing by the total attending the caucus. In cases of ties, delegates can be awarded by flipping a coin or drawing straws.

The Commissar expects this will lead to some strategic behavior, as groups of voters who might prefer other candidates may coalesce around a single “ABD” candidate to counter the Dean groundswell. Yet there are a couple of obstacles to such a process:

1. This process only happens at caucus sites, rather than at a higher level of aggregation. Gephardt may get the nod at one location, Edwards at another, and Lieberman at a third.
2. The caucuses only elect delegates to county conventions; as The Green Papers notes, the process for choosing congressional district and statewide delegates happens in late April, by which time the nomination will essentially be decided—and thus almost all of Iowa’s national convention delegates are likely to opt for the presumed nominee at that point, rather than following the caucus-goers’ preferences.

So, in the grand scheme of things: Iowa decides virtually nothing, and essentially is as important as today’s eminently forgettable D.C. non-binding primary, yet it’s been the center of media attention for two months. Great.