Last night, John McCain, Republican senator from Arizona, took his presidential bid to the deskside of David Letterman, independent ironist from Indiana. McCain is constitutionally possessed of an interest in high-risk maneuvers, and his visit to The Late Show (CBS) looked like a small demonstration of it on that plane where politics and entertainment explicitly meet.

If you're anything like me, then you watch an altogether unhealthful volume of cable news and understood the context. Three weeks earlier, the candidate had stood up the host at the last minute. The canceled appearance was the first casualty of McCain's brief "suspension" of his campaign to rush back to Washington and save the economy. In fact, it was the only discernible evidence of that suspension.

That night, Letterman, cheesed off that the senator was in fact moseying back to the capital, at one point showed a live internal feed of McCain, his face freshly powdered, submitting to an interview with Katie Couric. Since then, he had been working jokes about McCain's behavior into the ground—a fact all the more notable considering the long-running on-air rapport between the two, whose senses of humor vibrate at the same cantankerous frequency. Letterman's monologues had delivered a tizzy of reproach (only partly comic) and self-pity (mostly light-operatic). Bitterness is Letterman's stock in trade, crankiness his essence. How would the candidate face this force? With that special kind of self-deprecation, chummy and hammy, that politicians tend to adopt when bathed in talk-show stage lights.

Letterman's opening monologue was dedicated exclusively to quasi-political jokes. For every line that got within hailing distance of actual satire ("The entire balcony is filled with state troopers fired by Sarah Palin"), there were three stale wisecracks about the most easily caricatured features of public servants: At the previous night's debate at Hofstra University, said Letterman, John McCain brought up Barack Obama's relationship with William Ayers, "and then Barack Obama brings up John McCain's relationship with John Brown at Harper's Ferry." Hillary Clinton, he went on, had been in the audience at Hofstra: "Is it really a good idea to be leaving Bill alone at home?" Hearing that line in 2008, the listener must literally groan. It seemed that Dave would be playing it safely cynical.

In 2007, when McCain announced his presidential bid from The Late Show's guest chair, he nudged the band into blasting a few bars of "Hail to the Chief." On Thursday, Paul and the gang played him on stage with the Who's "I Can't Explain." Immediately pressed to discuss his cancellation, the senator grimaced, telegraphed abashment in a series of shrugs, and said: "I screwed up"—an efficient nonreply in its mixture of seeming candor and utter vagueness. The hair shirt he donned to atone for the trivial crime of displeasing our late-night neo-Cronkite doubled as a flak vest guarding against a less-trivial discussion about the entertaining stunt of the campaign suspension itself. Note also McCain's practiced dexterity in treating this as a light-hearted occasion to restate his history as a prisoner of war. Of watching MSNBC's Keith Olbermann—the loudest lefty on cable—take his place that night, he said, "I haven't had so much fun since my last interrogation."

Letterman received all that with big, genial cackles, but by the second segment, the air of hospitality was going slightly curdled as the host questioned McCain's tactics, his association with G. Gordon Liddy, and, most tensely, the readiness of his running mate. He had an agitated index finger. In a rare invocation of his private life, Letterman mentioned, like some plain-spoken swing voter at a town-hall meeting, his 4-year-old son, implying a lack of confidence in Sarah Palin's ability to protect the kid's future. McCain—who had been at his most relaxed and charming, the channeled anger of his debate performance stowed securely away—shifted gears. Is she qualified? "Absolutely," he said in a breathy tone of willed patience, as if Dave were a tender soul who had yet to see the light. The host eventually wheeled the chat around to conclude on an affable note, such that today's headlines have us understand that McCain made "amends" (the Wall Street Journal's Web site), that the two "made nice" (CNN), that they're "pals again" (USA Today). Working on the model of his great hero Ronald Reagan, McCain has developed sure showbiz instincts: What true American doesn't love a good reconciliation?