Riding around picturesque New Hampshire on John McCain's campaign bus not long ago, I found myself briefly dazzled by the candidate's willingness to chat up reporters for hours on end.

The not-so-subtle message: This is the real deal, a straight shooter, a politician unafraid to expose himself to the media jackals, speak his mind and take his chances.

Or was that just what McCain wanted me to think?

I had a similar moment of puzzlement while trailing Bill Bradley around Iowa a few months ago. He spoke in a quiet mumble, making no attempt to play to the crowd. Dressed in an ill-fitting sports jacket, he did not hide his annoyance at press questions he deemed pointless or superficial.

Clearly, a down-to-earth, unvarnished candidate. Or was he?

Journalists have heaped praise on these two men for their seeming abandonment of artifice. But perhaps we are just being manipulated by what one strategist calls "the candor pander."

This is the seventh presidential campaign I've covered or kibitzed around in, and I've never before sensed such a public hunger for this quality called "authenticity." After the humiliation that followed Monica Lewinsky's pizza delivery to the Oval Office, many Americans seem to be craving an alternative to the slippery pols with whom they have grown quite disgusted.

Sure, there's always been a longing for a "man of the people"--preferably one born in a log cabin, or at least a quaint small town--but there is something about this hype-filled age that has fed the yearning for the non-slick, the Uncola, the anti-Clinton.

Most voters make up their minds from a distance. I get to hover backstage as these candidates go through their daily drills. In the typical campaign, we are kept at bay, herded behind rope lines, fed predigested bits of information leavened only by market-tested anecdotes. We have little direct access to the president, governor, senator or any other candidate, relying instead on a phalanx of handlers, spokesmen and spinmeisters to filter and interpret the latest events.

Little wonder, then, that we media types tend to reward those who give us a peek behind the curtain, while penalizing those who are seen as overly remote or scripted. In the endless search for the "real" story, reporters are drawn--at least initially--to those who give the best impersonation of being real. And there's a normal human reaction: We like people who seem to like us.

Political operatives, interestingly enough, tend to be skeptical of too much reality. Paul Begala, a former aide to President Clinton, bristles at what he calls "running around and advertising your virtues as a truth teller. The candor panderers talk about talking straight more than they simply talk straight. The press goes gaga for it, but voters don't care."

Perhaps it's telling that those who have coached the office seekers see spontaneity as just another tactic. "Authenticity is often deeply phony," says Bill Kristol, the Weekly Standard editor and former GOP strategist. "The focus on authenticity follows from the focus on feelings. Clinton set a new standard when he said 'I feel your pain.' The next question for a candidate is, does he authentically feel those feelings--or is it a sham?"

Needless to say, neither George Washington nor Andrew Jackson worried much about looking empathetic, since most voters never saw them at all. (Lincoln was the first president to be glimpsed by his countrymen in photographs.) But in the age of the TV close-up and the "Oprah" confession, the politics of personality loom large in our national psyche. "The whole message-of-the-day, message-of-the-week is designed to sell certain qualities to the American people that may have little to do with the candidate," says Roger Simon of U.S. News & World Report. "Maybe authenticity now is when you get so good you believe in your own image."

Over the years, the media have been drawn toward blunt-talking mavericks who position themselves as bold--some would say self-righteous--critics of The System. Bruce Babbitt filled that role in 1988, Paul Tsongas in 1992, Pat Buchanan (from the opposite direction) in 1996. Such candidates generally soak up plenty of ink--and then lose.

McCain and Bradley, though, are running on more than just their opposition to the status quo. They are uniquely positioned because their backgrounds--one a war hero, the other a sports star--demonstrate that they are not merely politicians. Each man is running as much on his biography as on his position papers. That's one reason most of the media didn't dismiss their recent New Hampshire town meeting on campaign finance reform as a stunt; their past lives have somehow earned them the presumption of sincerity.

Anything that mars that image, in turn, carries a special whiff of hypocrisy. When Bradley acknowledged in November that he had been quietly working with Madison Avenue ad executives for 16 months, the unpackaged candidate suddenly looked like he had a team worrying about makeup and lighting.

McCain has taken his knocks for having a bad temper, but I like the fact that he lets other politicians have it now and then. Of course, the media debate over his two-fisted style means he can no longer allow even a glimpse of it in public. Thus we have the real McCain (a guy who gets mad) making jokes (about getting mad) to allay public concern (that he gets too mad).

One sign of alleged authenticity, oddly enough, is a refusal to babble on about private matters. Bradley has declined to answer questions about his favorite book, his favorite movie or the identities of his closest friends--and religion is totally off limits. "I've decided that personal faith is private, and I will not discuss it with the public," the Missouri native said on ABC's "Nightline."

By contrast, Texas Gov. George W. Bush surprised some viewers at an Iowa debate by proclaiming the importance of Christ in his life. "That answer could only be given in Bill Clinton's America, where you're supposed to authentically reveal yourself," Kristol says wryly.

McCain has also drawn the line at discussing religion. Beyond that, however, the Arizonan has talked freely about his foibles--from his long-ago fling with Marie, the Flame of Florida, to cheating on his first wife, to his role in the Keating Five influence-peddling scandal--for which he castigates himself loudly and repeatedly.

This makes McCain seem like a real, flawed human being. Yet it also reflects a strategy of inoculation, by being tougher on himself than any potential critic. So McCain wins either way.

Whether it's Bradley acting aloof or McCain doing his one-of-the-guys routine, neither man gives evidence of the old-fashioned political trait--classically embodied by Bill Clinton, more awkwardly by Vice President Gore--of trying to please every person in the room. After an administration that once conducted a poll about where the president should vacation, such an approach has a certain allure.

When it comes to policy matters, most candidates run a kind of Miranda campaign, determined not to say anything that can be used against them. With few exceptions, politicians like to leave themselves wiggle room and duck hypothetical questions.

But when Bradley was asked how he would pay for his $650 billion health-care plan, he did not resort to the typical duck-and-cover response. He told The Washington Post that if other financing methods didn't work, he would make a "decision then as to whether, if you didn't have enough, what you were going to do--cutting spending or increasing taxes."

Predictably, Gore's campaign immediately attacked Bradley for opening the door to a future tax increase. After a few days, however, Gore had to admit that he, too, couldn't rule out raising taxes under unforeseen circumstances--in other words, that his position was essentially the same as Bradley's.

In the coming weeks, both Bradley and McCain will face a period of tougher media scrutiny. News organizations don't commit the resources for a full-body frisk unless they believe that a candidate is not merely entertaining but actually might become president. The question now is whether Bradley and McCain can stick to their unorthodox styles as the investigations get tougher and the media mob grows larger.

There is ample reason for caution. Perhaps no politician has rocketed to stardom on the basis of a no-bull persona as has Jesse Ventura. Like McCain and Bradley, the Minnesota governor used his previous fame--as Jesse "The Body," the wrestler in a feather boa--to win high office. And he thumbed his nose at political correctness, growling about every issue under the sun and trumpeting his bad-boy past (using marijuana and steroids, not wearing underwear, trading an ammunition belt for a hooker's services).

Yet even Ventura discovered that the voters can only take only so much candor. The governor plummeted in the polls after proclaiming religion to be a "sham" for the "weak-minded" and sounding off about a military-industrial conspiracy to kill JFK. Now, he tells Time magazine, "I'm still myself. . . but I find myself not giving opinions on things that have nothing to do with government."

Even authenticity, it seems, has its limits. There's a fine line between brutal candor and tiresome eccentricity. Letting it all hang out can hang someone who does it recklessly. Voters may prefer natural grass to Astroturf, but they don't like the muddy result when it rains.

In the end, it's hard to know whether a McCain, Bradley or Ventura is unscripted or just playing a different kind of role. Each offers a take-me-or-leave-me personality that doesn't seem carefully calibrated by focus-group research. But politicians, like celebrities, are always onstage. They may riff to their hearts' content, but they can never be unaware of the spotlight. And that, in some undeniable way, means they are always engaged in performance art.

Howard Kurtz covers the media for The Washington Post.