TUESDAY -- Jon Stewart, the host of Comedy Central's " The Daily Show , " is perhaps the most talented of his peers -- far more quick than the frat boy Craig Kilborn, more cerebral and less grating that Conan O'Brien. That's what makes the recent lurch of his show into polemics so disappointing.

Part of the magic of Stewart's show, like those of his elders David Letterman and Jay Leno, obviously involves poking fun at political figures such as President George Bush and Vice President Dick Cheney. Stewart's very good at that. But Stewart in the last couple of weeks has permitted comedy to lurch into politicizing. I didn't like it, for example, when Stewart and Robin Williams yukked it up about Secretary of Defense Donald Rumsfeld's warnings about Iraq. But at least Stewart and Williams both make their livings as entertainers, and if Rumsfeld - a Stangeloveian figure if ever there was one - isn't open to parody, then who is? But even that doesn't explain what Stewart did last night. Stewart's guest on last night's program was none other than Scott Ritter, one-time United Nations weapons inspector turned anti-war activist.

If ever there was a poster-child for humorlessness, Ritter is it. He showed up on Stewart's program, earnest-faced and wide-eyed, brandishing a copy of his 1999 book, Endgame: Solving the Iraq Problem - Once and For All . Ritter is the former weapons inspector whom Saddam Hussein tossed out of Iraq when he searched too strenuously for biological weapons in 1998. His expulsion preceded Hussein's ejection of other inspectors that year, which lead, in turn, to President Bill Clinton's decision to launch Operation Desert Fox in December. When Ritter made it to Washington in September of that year, I watched at how the former Marine electrified the congressman at the House International Relations Committee. He told a frightening tale -- one of how Hussein easily evaded the UN inspections regime and how much of a threat Hussein posed.

We didn't hear any of that on the Stewart program last night. " No one has put forward any facts " to show that Hussein has chemical or biological weapons, Ritter said. Here's a guy who almost exactly four years ago was ringing every alarm bell in the book about Hussein -- back when inspections were taking place -- now telling everybody not to worry about it. Stewart, of course, didn't call Ritter on his change of tune. Instead he played into it. " Then help us out. Why the fetish? " asked Stewart, oblivious to the fact that Hussein, unlike even the leader of North Korea had used either chemical weapons or missile weapons against three different enemies during the last two decades. (Memo to Stewart: No other leader has employed chemical weapons against his own people, as Hussein did in Halabja in 1988 and no other leader has launched more than 20 long-range missiles at another nation either as Hussein did against Israel in 1990.)

Stewart, finally, pitched Ritter a softball: " So you think [getting] weapons inspectors would solve the problem? " Answered Ritter: " That's right. No war. " If Hussein's so amenable to real weapons inspection, why did Ritter get kicked out of Iraq in the first place? We didn't hear that from Stewart either, only: " Thank you so much for clearing up some of the misconceptions. "

Now Stewart's show is in a quandary. If he really wants to get away from comedy -- again, there's nothing funny about Ritter -- and clear up some misconceptions, he ought to have Ahmad Chalabi, the leader of the Iraqi Democratic opposition on as a guest, or at least Ambassador Richard Butler, who was Ritter's former UNSCOM boss. If he wants a watchable show, he ought to drop the television version of pamphleteering.