David Yepsen of the Des Moines Register was on Howard Kurtz's Reliable Sources this morning. In defense of the Iowa caucuses, he made this point:

This is the first time that political activists around the country have a chance to have their say about who ought to be president. Media people have had our say. The money people have had their say. Now this is grass roots activists. And that is, to me, one of the things that is defensible about this caucus is that it is not typical voters, it is party activists.

They go out on a cold January night. They stand up. They sit around. They talk politics. And so it really is the core of each party. If you look at the kind of people that go to a precinct caucus, they look an awful lot like the same sort of people you see at the national convention.

There are 3 million people in Iowa's 99 counties, but it's expected that only 200,000 will come out to caucus. So the caucuses may not reflect the preferences of the voters in Iowa -- only the preferences of politically active voters.

Just something else to keep in mind.

Update: The Des Moines Register has this article today on key voters.