During the 1960 presidential race, New York Times political reporter James Reston wrote that the campaign had come down to two basic tests: "Who can stand up to Nikita Khrushchev. And who can sit down with Jack Paar." Forty years later, at least half of Reston's axiom has become a nearly ironclad principle. America may not know where the 2000 presidential hopefuls stand on the world stage, but millions have seen how they perform on TV's late-night couch. Television, which was just starting to assert itself in the Kennedy-Nixon race, is now a main source of election coverage for three out of four Americans, according to the Pew Research Center for People and the Press. Given that, maybe the only thing that matters today is how well candidates do with "Paar" - or rather, with Jay Leno and David Letterman, Paar's latter-night descendants. Think I'm kidding? Try this little test on your co-workers. Ask them which Republican candidate was accused of writing negative campaign brochures about his opponent in Michigan. Then ask them which one was half an hour late to an interview with Leno last week. (Answer to both: John McCain.) You'll immediately smoke out the political junkies in your office with the first question. It has been a hot topic for weeks among the Beltway insiders who show up on CNN, Fox News, "News-Hour" and other TV bull sessions. Consider that more than 11 million viewers last week caught either McCain's tardy turn with Leno or George W. Bush's comically inept satellite interview with David Letterman. That's nearly three times the combined viewership for the two prime-time presidential debates CNN aired last week (4.1 million). Millions more saw Bush in a more adroit appearance with Leno Monday night. And it's not just how many are watching, but who. Younger viewers who tend to avoid cable and network news flock to Leno and Letterman. That's why candidates, especially underdogs looking for new blood, try to get themselves booked on late-night shows. It's what prompted candidate Bill Clinton in 1992 to blow his own horn, literally, on "The Arsenio Hall Show" and give Black Entertainment Television's popular "BET Tonight" an interview the day before the tough 1998 elections. Candidate Bob Dole picked up that cue, making regular appearances on any late-night show that would have him, including "Late Night With Conan O'Brien" and "Saturday Night Live." (After his 1996 defeat, he did a sketch with Dole impersonator Norm Macdonald.) Bill Bradley has made the circuit several times since the '96 election. He has paneled with Dave, Conan and Charlie Rose. Al Gore hasn't been as prolific - he made hay for years off his 1993 visit to Letterman's show - but early last month, as Bradley was mounting a late surge, Gore finally darkened Leno's doorstep. (In the "Tonight Show" tradition, Leno flattered him with jokes, e.g., "Earlier today, computer hackers actually shut down Al Gore for two hours.") With the GOP race heating up, and public interest in the candidates growing, bookers for the late-night shows got into the fray. Letterman, issuing a typical caustic challenge, dared Bush to come on his show and "settle once and for all whether (he) is a colossal boob or not." In reality, the "Late Show" staff was trying to book Bush before his scheduled appearance Monday on the "Tonight Show." Both shows treated the Texas governor like an A-list movie star with a blockbuster to plug. But in their eagerness to get their man the maximum exposure, Bush's handlers agreed to something they'd later regret. Since Bush couldn't get to New York, Letterman interviewed him March 1 via satellite from St. Louis. Right away, Bush dug himself a hole, breaking one of the Letterman show's cardinal rules, "Thou shalt not be funny with Dave." The host asked how he managed to look so youthful and rested after all that campaigning. Bush grinned and said, "Fake it." The studio audience tittered nervously, sensing what would come next. "Is that pretty much how you plan to run the country?" Letterman shot back, as the crowd roared its approval. Bush then tried a couple of tacky heart-related jokes, which were further mangled because of the satellite delay. Bush's televised pratfall, seen in some 5 million homes, could have put him at a disadvantage, but McCain was unable to capitalize in his panel with Leno. The senator instead delivered one of his trademark odd moments of spontaneity, emptying his pockets of several lucky trinkets given to him on the hustings, including a compass, a Hopi tribal feather and a flattened penny ("so (my) campaign won't be run over," he joked). "Nothing wrong with being a little superstitious, is there?" said McCain, sensing the drop in cabin pressure. "No, no," said Leno. "It's just a little (cough) frightening." The "Tonight Show" actually has a reputation for friendliness, as Governor Bush found out on Monday. Leno served up so many softball questions during that interview, he might have had to ice his arm after the show. Among other hot-button topics, Bush discussed his mother, former first lady Barbara Bush, his late father-in-law ("He was a good West Texas man they lowered their standards and let me into the family") and his reputation as a cheapskate. "I'm thrifty!" Bush corrected Leno. "I'm going to be tight with your money, all of that money you make." "Wow, you're good!" Leno said. 'I'd say pick Leno' The Pew Research Center reported in January that 80 percent of all voters under 30 were getting their information about political candidates, at least some of the time, from "non-traditional sources": MTV, "Saturday Night Live" and, yes, Jay and Dave. Nearly half of young voters even said they "occasionally learned something about the campaign" from late-night TV. At least one commentator thinks that's not such a bad thing. Bob Somerby, a Washington political satirist, stand-up comedian and frequent guest on Fox TV, has been chronicling the foibles of the Washington press corps in his widely read Internet column, The Daily Howler (dailyhowler.com). "If I had to pick one source of information," Somerby said, "I'd say pick Leno." To reach Aaron Barnhart, phone (816) 234-4790 or visit the TV Barn Web site at www.tvbarn.com @ART CAPTION:John McCain banters with Jay Leno on "The Tonight Show." @ART:Photo (color) @ART CREDIT:NBC >>>

