CBS's coverage of the Olympics verified something I've long suspected - the reason "The Tonight Show" beats the "Late Show" in the ratings is because Jay Leno is on NBC and David Letterman is on CBS.

NBC is, of course, a far stronger network in prime time. And by far Leno's biggest night every week is Thursday, when he benefits from the huge lead-in that "Friends," "Seinfeld" and "ER" give him.But during the Olympics, the situation was reversed. Although CBS's prime-time ratings weren't what the network hoped they would be, they were still well ahead of the competition. And the "Late Show" beat "The Tonight Show" both weeks that CBS had the Nagano Games on in prime time.

Not only that, but Letterman's biggest night of the Olympics run (his highest ratings in almost three years) came on Friday, Feb. 20, which was also the night of the women's figure-skating finals - which attracted CBS's highest ratings of the Games.

Coincidence? Absolutely not.

The fact is that when Letterman was beating Leno in the ratings, CBS was the top-rated network in prime time. And Letterman's fall from the top coincided with CBS's collapse in prime time.

All of which lends credence to the theory that if somehow the "Late Show" and "The Tonight Show" were to swap networks, Letterman would be beating Leno consistently.

AN EXPLANATION: Some callers have wondered how CBS's coverage of the Nagano Olympics could be the third-most-watched event in television history and the second-lowest-rated Winter Games since 1968.

The answer is fairly simple. A ratings point represents 1 percent of American homes equipped with televisions. As the U.S. population has increased, the number of homes represented by 1 rating point has increased.

Thus, while the '76, '80, '84, '88 and '92 Winter Games had higher ratings, more homes were turned in to the '98 Games.

UNEVEN `WARS': "The Pentagon Wars" is, at turns, amazing, amusing and plodding. In other words, it's about as consistent as Utah's weather.

This HBO movie, which premieres tonight at 9, is amazing because it's based on actual events - the attempt by the powers that be at the Pentagon to push through production of the seriously flawed Bradley Fighting Vehicle.

It's amusing because it's just so darn weird. Phony tests with substandard East European armaments that prove nothing. Tests with Bradleys full of sheep. (Really!) The sheer stupidity of spending billions of dollars - and wanting to spend billions more - on something that just didn't work.

There are, in fact, some hilarious moments in "The Pentagon Wars." But only moments.

Cary Elwes stars as Col. Burton, a straight-arrow good guy who wants to do what is right. In his way is Gen. Partridge (Kelsey Grammer), a huffing, puffing buffoon who wants the Bradley built no matter what. When Burton starts asking uncomfortable questions, Partridge pulls out all the stops to keep the project going.

But the hilarious moments are too infrequent. There's a lot of boring exposition along the way, and Grammer's character is so cartoonish he detracts from what was supposed to be the fact underlying this movie.

In other words, "The Pentagon Wars" has its moments - but there aren't enough of them to make it a consistently watchable movie.

(Although "The Pentagon Wars" isn't rated, it's full of foul language that would have gained it an R if it were released theatrically.)

REAL YOUNG WORLD: The Disney Channel's "Bug Juice" is the story of a bunch of kids who spend the summer at a camp and have their lives taped.

Think "The Real World," only with 12- to 15-year-olds.

Actually, "Bug Juice" is the same sort of almost insidiously absorbing programming - except that these youngsters are considerably less self-absorbed than the whiny brats on "The Real World."

"Bug Juice" kicks off tonight at 9:30 as the kids arrive at Camp Waziyatah in Waterford, Maine. It's a camp for both boys and girls with a multiracial mix.

And it's a fun, funny and sometimes painful look at adolescence - one that doesn't come off a script-writer's keyboard. It's about activities and friendships and homesickness and boy-girl interaction.

Kids ought to like it. Adults might not admit it, but they'll probably like it, too.