(UPDATE: You can see the entire interview here, or at Crooks and Liars.)

You've got to hand it to David Letterman: when he's engaged and interested in the person he's interviewing, he can be one of the toughest in the business, even tougher on his guests than those who consider themselves "hard news" people (are you taking notes, Tim Russert?).

Take, for instance, Dave's smackdown of Bill O'Reilly last night. You can see a clip of it on the Late Show web site. After Dave greeted Bill with a pleasant "How was your holiday?", Bill responded smugly, "I had a nice winter solstice." This must have set Dave off, because he spent the first half of the interview listening to then dismissing O'Reilly's crusade against the "War on Christmas," voicing most Americans' opinion on this non-story: "I ignore stuff like that, it doesn't really affect me, I go ahead and do what I want." Then, as O'Reilly went point-by-point through each town that has nuttily legislated against even secular Christmas displays, Dave exasperatedly asked him, "Isn't this the kind of thing where every once in 20 years, someone says, 'we have to put diapers on the horses,' and that's all there is to it?"