It took all of seven seconds for David Letterman to cut Rod Blagojevich off at the knees during the disgraced politician's "Late Show" appearance last week.
The episode was a reminder of Letterman's least appreciated skill. The monologue is fun, the "Top Ten" list an inspired creation, but often the best work on the "Late Show" comes when Letterman interviews the people invited to sit across from him.
Letterman rarely avoids or glosses over difficult subjects, drilling in with a journalist's tenacity that he sometimes masks with a self-effacing attitude, and sometimes not. He uses humor to lighten a mood or make a specific point. His personality rarely allows him to conceal what he's really thinking, setting him apart from most journalists.
Many of those qualities were in evidence when the former Illinois governor stopped by on his impeachment media tour.
"Why exactly are you here?" Letterman opened, summing up popular bewilderment about the impeached governor's appearance schedule.
Blagojevich unwittingly served up a straight line, telling Letterman that he had been wanting to be on his show in the worst way for a long time.
"Well, you're on in the worst way, believe me," Letterman responded.
That was it. Blagojevich was impossible to take seriously from that moment. But they did settle into a serious conversation, and for an entertainment show, the "Late Show" came well prepared, playing a tape of Blagojevich and his brother talking about a payment. His administration is accused of trying to shake down seekers of state contracts for campaign contributions.
"So, now, as I recall, there were 13 articles of impeachment leveled against you," Letterman said. "So you're telling me each one of those was a misunderstanding?"
Later, Letterman used a laugh line to deflate another Blagojevich assertion that he had done nothing wrong.
"Do you use shampoo or conditioner?" Letterman asked the helmet-haired politician.
Letterman's show hearkens back to talk shows of old hosted by Jack Paar, Johnny Carson and Dick Cavett, where discussions often were more than just entertainers hawking their latest projects, said Neal Gabler, author and cultural critic. As an interviewer, Letterman can cut through the thickets, he said.
"He does to a limited extent with political interviews what he did earlier to a talk show in general, " Gabler said, "which is deconstruct it."
Letterman rode John McCain hard in last year's campaign, even after the GOP candidate acknowledged his error in canceling an earlier appearance. He confronted McCain directly about people in the candidate's past when the Republican talked about Barack Obama's associations.
The talk show host also took a personal approach by asking McCain if he really thought Sarah Palin was the best person to be vice president. "In your gut, in your stomach — you're a smart, tough, savvy guy — if I were to run upstairs and wake you up in the middle of the night and say is this really the woman to lead us?" McCain said that she was.
"He has an ability to take things in an odder and sillier direction than a journalist," Burnett said. "He can make points in very powerful ways by being funny."
Probably the most enjoyable times are when Letterman has as guests celebrities who are better known for their names than for their talent. When Paris Hilton came on shortly after a jail stint, Letterman peppered her with questions about the food, her treatment, whether she got any exercise. He knew exactly what he was doing.
"I've moved on with my life so I don't want to talk about it anymore," said an exasperated Hilton, who was on to promote a fragrance.
"This is where you and I differ," Letterman said. "Because this is all I want to talk about."
He skewered Spencer Pratt of "The Hills," particularly when Pratt talked about people paying him thousands of dollars just to appear at their nightclubs.
"Does he bring a pony?" Letterman said. "Have kids take a picture with it?"
For a comic, Letterman seems to have a greater seriousness of purpose after the past few years, since he had a son and major heart surgery. You can see it, Burnett said, in his greater interest in environmental subjects or in bookings of guests such as Thomas Friedman, columnist at The New York Times.
You can also sense it in Letterman's lack of patience with guests with whom he disagrees politically, when his pricklish personality emerges. It was most pointed in discussions with Fox News Channel's Bill O'Reilly as they faced off over peace activist Cindy Sheehan; Letterman believed that O'Reilly was wrong in criticizing a woman who lost a son in the war.
"I have the feeling about 60 percent of what you have to say is crap," Letterman said.
Such moments make for great TV but have a built-in risk.
"There are times when you are going to lose the battle with particular viewers," Burnett said. "But, ultimately, I believe ... that you win the war. I think people respect someone who sticks to his guns."