When CBS announced in early 1998 that Craig Kilborn would replace the departing Tom Snyder as host of The Late Late Show, the powers-that-be at Comedy Central were not pleased. Kilborn, who had been the anchor of the satirical newscast The Daily Show since its debut in the summer of 1996, was one of the cable channel's few bona fide stars, and they had hoped to keep him around for a while.

They knew they couldn't stop Kilborn from jumping ship, but he was under contract to Comedy Central through summer 1999, and they tried their best to at least make sure CBS didn't start celebrating his signing while he was still on The Daily Show. Comedy Central sought an injunction to keep him from making a high-profile promotional appearance for the network but eventually agreed, with some reluctance, to let Kilborn out of his contract a few months early.

In the meantime, the comedian Jon Stewart -- who at one point had been considered Mr. Snyder's most likely successor at CBS -- was hired to take over behind the Daily Show desk.

Some six months after Kilborn began his tenure as a late-night talk-show host (and eight months after Stewart replaced him on The Daily Show), it's hard to understand why Comedy Central was so upset about losing him.

Stewart, who is blessed with both a quick wit and an understated, self-effacing charm, has breathed new life into a show that hadn't even seemed to need it. Kilborn, in contrast, often appears to be gasping for air. He seems most at ease doing "In the News," a seven-to-eight-minute segment near the beginning of the show that allows him to reprise his news reader role from The Daily Show, although the quality of the writing is spottier and not as smart as it was, and continues to be, on Comedy Central. (Sample Daily Show news joke: The voters will decide whether Bill Bradley or Al Gore is "the bland technocrat to be defeated by that cokehead George W. Bush." Sample Late Late Show news joke: Both sides in the Mideast peace talks say that if they can't reach an agreement on a peace accord, "they might be willing to settle for a Honda Accord.") But the bulk of The Late Late Show casts Kilborn in the traditional role of celebrity interviewer, and not only isn't he very good at it, it's hard to tell if he even cares whether he's good at it. When he interviewed a less-than-superfamous fashion model plugging her new cookbook, his end of the conversation included this observation: "So you're a model who actually cooks. This is kind of cool." When Kevin James, the star of the CBS sitcom The King of Queens, jokingly claimed that ABC had moved the starting time of Monday Night Football from 8 to 9 P.M. because it didn't want to go up against his show, the following exchange ensued:

KILBORN: That's --

JAMES: It's pretty cool, huh?

KILBORN: Yah. Ha-ha-ha-ha.

Of course, Conan O'Brien seemed equally lost when he began his career as a talk-show host six years ago, and he has proved that it is possible to grow on the job. Kilborn, too, may get better and more comfortable with time. But even in O'Brien's first year on the air, when the screen fairly dripped with flop sweat (and none other than Jon Stewart was rumored to be waiting in the wings to replace him), there was something endearing about him. Although he affects his own version of the glibly ironic stance that has been de rigueur for late-night hosts since David Letterman showed everyone how to do it, O'Brien has always given the impression that deep down inside he's a sweet guy who just wants us to like him. Ultimately, it was that quality that kept at least a coterie of loyal viewers tuning in until he found both a unique comedic voice and a sizable audience.

Kilborn is another story. When he was anchor of The Daily Show -- a job that involved reading the news, doing a brief celebrity interview and otherwise functioning as a kind of ringmaster ushering correspondents and commentators on and off the set -- it was possible to believe that he was an actor pretending to be a vain, empty-headed pretty-boy newsman. Now that he has a whole hour to fill all by himself, it is beginning to look as if he may really be vain and empty-headed. Could it be that deep down inside, Craig Kilborn is shallow?

If Conan O'Brien wants us to like him, and Jon Stewart seduces us into liking him, Craig Kilborn practically dares us to like him. It almost doesn't matter whether his endless preening and posing and his "But enough about me, what do you think about me?" attitude are genuine or a put-on. The important thing is that they're annoying, and that they tend to put an awkward distance between him and both his audience and his guests.

And Kilborn's show is so self-referential it hurts. It is full of jokes that intentionally go nowhere and other devices meant to let us know that he knows that we know how phony it all is. A recent monologue included a gently self-deprecating joke (the punch line had to do with his considering himself a "dweeb"), which he followed by lunging toward the camera, pointing at it with both index fingers and shouting: "Self-deprecating, baby! That's me! Yeah!" A little of that sort of thing goes a very long way.

Ratings for The Late Late Show are so far not significantly different with Mr. Kilborn as host from what they were when Snyder had the job, and despite its youth-oriented makeover, the show continues to get beaten by NBC's Late Night With Conan O'Brien. Ratings for The Daily Show have risen slightly since Stewart took over.

The idea of simultaneously conducting a talk show and mocking the conventions of the genre was pretty radical when Letterman started doing it in the early 1980's. But these days such mockery is a talk-show convention, and Kilborn is probably going to have to be more than just the most sarcastic kid on the block if he ever hopes to stand out from the crowded late-night pack.

Meanwhile, the irony quotient seems to have diminished considerably on The Daily Show, where Stewart delivers the news with more of a conspiratorial wink than a condescending smirk.

For a while it seemed as if the correspondents' reports that are a vital feature of the show had degenerated into an endless set of variations on a rather cruel theme: making fun of people for being in some way eccentric, misguided or simply not very bright. There's still some of that bullying spirit in the air. But lately -- presumably at least in part because of Stewart's influence, and perhaps also because it's getting harder to find people naïve enough to let themselves be embarrassed on camera -- it seems as if the subjects of these reports are in on the joke more often than not.

This added degree of complicity makes the reports no less funny, and it often makes them downright endearing. Take the recent piece in which Vance DeGeneres, one of the driest and funniest of the Daily Show correspondents (and, yes, Ellen's brother), examined a campaign to persuade the city of Philadelphia to erect a monument to Larry Fine of the Three Stooges. It was clear that everyone being interviewed, including Fine's sister, knew there was something inherently silly about the whole thing. But correspondent and subjects alike played it just straight enough to let the humor speak for itself.

Some of the special features presented near the end of the show, like the segment devoted to local television commercials, remain mired in the ridicule-people-for-being-less-hip-than-us mentality. But the best of them -- notably "God Stuff," in which John Bloom (a k a Joe Bob Briggs) presents clips of television evangelists at their most absurd, and "Out at the Movies," in which Frank DeCaro offers campy and often catty film reviews -- are among the funniest things on television.

Stewart holds it all together deftly. He interacts with the correspondents far more than Kilborn ever did, sending the message that even though its official name is now The Daily Show With Jon Stewart, the show is a team effort rather than a star vehicle. His celebrity interviews are sharper and funnier than Kilborn's were, although the edgy playfulness of "Five Questions," the trivia quiz with which Kilborn ended his interviews, is missed. (Kilborn took "Five Questions" with him to CBS, and it is one of the few consistent highlights of The Late Late Show.)

The change of hosts has had only one obvious downside for The Daily Show. In the words of Madeleine Smithberg, the co-creator and executive producer, the show has lost "the crystal-clear joke that we were a parody of the news."

"You really believed that Craig was that guy behind the desk," Ms. Smithberg said in an interview. "He looked like everyone you've ever seen on TV. Jon Stewart has an unbelievable range of things that he's capable of doing, but he delivers headlines like a guy telling jokes. He's brilliant, but you don't really believe he's a news anchor."

It could be that The Daily Show was the ideal environment for Craig Kilborn, whose dead-on imitation of an anchorman helped give the show its identity. And although his syndicated talk show of a few years back was a ratings disaster, that may ultimately be the ideal environment for Jon Stewart, who can ad-lib with the best of them and conduct interviews in which he actually appears to be paying attention to what is being said.

Perhaps one day he'll get another shot at it. For now, though, Stewart seems very much at home on The Daily Show. A lot more at home than Kilborn seems away from it.