WHY HAS the 1988 presidential campaign "show" opened as a cross between a demolition derby and a game of trivial pursuit? What in the political culture has changed? The politicians? The press? The electorate? The national mood? And what sort of candidate is likely to be the last man standing when the curtain falls 13 months from now on this withering spectacle?

As a political reporter who's been out on the presidential trail all year -- gasping at its slips and spills, groping for meaning in its sudden wrecks -- I offer a few theories:

The thread that runs from the troubles of Gary Hart to those of Joe Biden, Mike Dukakis and Pat Robertson to the as-yet uncommitted gaffes and undissected warts that will draw the next round of headlines, and the next, is that they're about biography, authenticity, self-portraiture.

For better or worse, this has become the core material of presidential politics. Historian James MacGregor Burns, writing in 1984, called it the politics of personalismo, "a profound, peverse, almost revolutionary change" that has taken place in the past decade in the way we choose our leaders.

We live in an era, he observed, where the "issues" seem to have little coherence or patterning. For example, to be liberal on economic policy can leave one crosswise with liberals on social or foreign policy. This confusion devalues party labels. "Lacking the moorings of party or the anchors of ideology," Burns wrote, "the voters are adrift."

So they are left to judge candidates the way a People-magazined, celebrity-soaked culture encourages them to -- as if they're watching characters in a soap opera. Egged on by the media, they become spectators to the tactics, episodes and morality plays of a campaign, to the thousand little deceptions that are a part of a candidate's (and most everyone else's) self-presentation.

Hart's name and age change and pattern of reckless behavior, Biden's borrowing of other politicans' words and ancestry, Dukakis's handling of a campaign affair that belied his image of righteousness and managerial competence, Robertson's cleaning up and puffing up of parts of his resume -- these become the tests of political survivability.

As the fatality rate has mounted this year, a morbid and self-perpetuating fascination with the process has taken hold. "I'm just waiting to see who self-destructs next," said Dan Chase, a high school teacher attending a Jackson speech in Iowa.

The quip captures the weary cynicism of the season. The voters -- even the nearly half of them who won't bother to exercise their franchise next November -- are hip to all the manipulations that lie behind self-presentation in a media age. Consider, from a different realm, the Isuzu ad. It's been fabulously successful because it makes the viewer an accomplice in laying-bare Madison Avenue's dirty little secret: Of course we lie! We lie all the time!

A commercial like that works only in the right climate. It struck a chord this year because it reached a country in a grumpy mood. That grumpiness has several sources: disillusionment over President Reagan's fall from grace as a result of Iran-contra; anxiety that today's pockmarked prosperity will give way to tomorrow's bill-paying; concern that, even as the nation revelled in the Reagan feel-good philosophy, it was losing its edge in a changing world economic order.

The breast-beating patriotism of the mid-1980s is now passe; so, too, is the suspension of disbelief toward the president who ushered it in. With Reagan, there came a time, early on in his first term, when his inattention to fact ceased to interest the public. Even if the public had doubts about some details of his conservative platform, they liked Reagan's toughness, his gut instincts. They liked how he made them feel, the way he handled the job. "He wrest{ed} from us something warmer than mere popularity, a kind of complicity," wrote Gary Wills, in a recent Reagan biography.

That special bond is now sundered. Reagan has escaped the brunt of the fallout; the public's investment in him has been too great. But heaven help his would-be successors. They'redrowning in the backwash of the disillusionment with him. "It's the jilted lover syndrome," said Democratic pollster Harrison Hickman. "It's doesn't mean they won't want to fall in love again; they just don't feel like going on a date right now."

On the campaign trail, one hears from the voters, time and again: "What difference does it make what they tell us? They do something different when they get in office, anyway."

This sullenness is a precondition for the anti-heroic flavor of the presidential campaign now underway. It fuels a presumption within the press, shared (though with less fervor) by the public, that the process of self-presentation needs to be monitored more rigorously than ever.

"Voters are dying to get a look at the candidates with the bark off," said GOP pollster Robert Teeter, who is working for Vice president Bush. "They want to see them when they're not being packaged and advised."

"We see our politicians as people trying hard to project an image, and we're frustrated because we fail to see the person behind the image," said Ned Kennan, a social psychologist who has advised numerous candidates, including during this campaign, Rep. Richard Gephardt (D-Mo.).

The candidates and their handlers -- careful analysts of these wants -- search for ways to satisfy them. That's why men like Teeter and Kennan are hired in the first place. Ever more so, their strategies call upon the candidate to undress, figuratively, before the public.

To take the most current example, consider the events surrounding Bush's formal announcement for the GOP nomination last Monday. It might seem that, after 25 years in public life, Bush's stand on the issues would be well-known. But he and his aides labored over the crafting of an ideology (turns out he's a moderate this time), and produced a series of positions on the proposed INF accord, the capital gains tax, etc.

They also strategized, of necessity, about the so-called "wimp" issue. This, they know, is Bush's special burden in the hazing from the media that his announcement unleashed. (Cover story headline in the current Newsweek: "Bush Battles the Wimp Factor"). Should he take an aggressive tack, turning these incessant inquiries into advertisements for strength and stature:("The soldiers I was shot down with in World War II didn't think I was a wimp . . . . The people I led at the CIA didn't think so either . . . " etc.)? Or should he show a softer, more human side, talking about the strength that came from having to watch an infant daughter die of leukemia? Or is that too maudlin?

Bush has tried both approaches. He has also tried ignoring the issue. No matter which way he goes, he is trapped. The press writes about it, pollsters ask voters about it (51 percent agree that the "wimp" image will be a serious problem, Newsweek reports in self-fulfilling prophecy), Doonesbury, Carson and Letterman have their fun with it. "The more he protests he isn't a wimp, the less people think of him," noted Douglass Cater, president of Washington College, a former adviser to President Johnson, and a longtime observer of the political process.

Bush is not alone in feeling the need to make these kinds of calculations. Senator Minority Leader Robert Dole (R-Kan.), during three decades in politics, never spoke publicly about his war injury, or the impoverishment of his grandparents. Now he does, daily, as part of his stump speech -- presumably to convey a sense of compassion, to mitigate the "hatchet man" image he is anxious the press not resurrect from his run for the vice-presidency in 1976.

Dukakis, after months of prodding from his advisers, began his presidential campaign this past spring by talking about a subject he had avoided in four previous runs for the governorship of Massachusetts -- the story of his immigrant parents. This, presumably, to warm up a cool technocrat's image.

Sen. Paul Simon (D-Ill.), seeing that this is the year of "character," campaigns as the uncola candidate. He tells voters he's too independent to listen to the slick media advisers who want him to get rid of the bowtie and horn-rimmed glasses that brand him a "square." The advisers, of course, know he's got the hottest gig going.

Now, consider the press role in this unsatifying, image-driven equation. Leave aside the question of whether Hart and Biden "got what they deserved and therefore the process worked" or whether they were victims of press overkill and caricature.

Let's stipulate, in either case, that the press has a known tendency to do whatever it does to excess. And that, at the moment, it's doing a lot of character and image policing. As Thomas Cronin, an American politics professor and scholar of the presidency at The Colorado College, observed: "You guys strip those candidates naked. And there are more of you working at it, harder and better than ever before."

Lots of voters, to say nothing of the candidates, object to the hanging judge aspect of the press role.

These guys can't win, it seems. Consider the Dukakis espisode. In the first blush of his "crisis," he was beaten up in his hometown papers for publicly hesistating for four hours before he fired John Sasso, the top aide who had prepared the infamous Biden "attack video." As weeks have passed and the initial Sasso transgression -- which, after all, was not a classic dirty trick in that the material released was true -- has come to be viewed in a less harsh light. Revisionist criticism is cropping up in and out of the press. "The candidates are so sensitized to the rhythms and urgencies of the press that they completely lose any sense of self," said Cater. "Dukakis could have said, 'I've got a damn good adviser who happens to like to play tricks. No, I'm not going to fire him; it wasn't a crime.' Instead, he manages to look like he doesn't know how to stand up."

Similarly, there are those who argue that, even after a couple of weeks of press pounding on plagiarisms and related misdeeds, Biden got out of the race prematurely. Others (though fewer) think Hart could have survived the Monkey Business.

The point in all these candidate bouts with the press is the same: there is a functioning marketplace of public opinion, which acts as a judge. It is a market, for all the obsession with the superficial and the ephemeral, that does respect dictates of fair play. And like all open markets, it has built-in self-correcting mechanisms. If the press goes beyond the pale in its reporting, it creates opportunities for its "victims" to use those excesses to fight back.

So far this year, the candidate who appears, at least for the moment, to have fended off what he called the "feeding frenzy," is Pat Robertson. He denounced press reports about his misstating his wedding date change (to conceal the out-of-wedlock conception of his first child) as "reprehensible" journalism, and battled point-by-point on several other irregularities in his resume. At the moment, the story has died.

Meantime, Jesse L. Jackson and his wife, Jacqueline, have moved preemptively -- making it clear in several recent interviews that they consider any "bedroom" reporting about Jackson to be out-of-bounds, undignified and without place in a presidential campaign. So far, no one's done any such reporting -- though what Jackson calls "rumors about rumors" persist.

It's no accident that the two reverends seem best positioned to fend off whatever the media's character cops may toss at them. They each have an intensely loyal -- if narrow -- core of support that other candidates lack. Revealed character flaws may yet prevent both from broadening their appeal, but within their respective flocks, they're protected by the suspension of disbelief that charismatic leaders engender.

That raises two last questions -- what is gained and lost when campaigns become demolition derbies, and what is this phenomenon likely to produce next November?

What's gained is an untidy, sometimes harsh, often trivialized -- but still functioning -- candidate inspection system that is molded to the political culture of its time. And for all its faults, the flaws exposed by this process that have proved fatal to candidates have, so far, struck at the core of what the electorate seems to value most in its presidents -- authenticity and good judgment.

What's lost -- or at least jeopardized -- are the kinds of leader-follower relationships that have been most satisfying to this nation in the media age, for example, the presidencies of Reagan and John F. Kennedy. (It's not a pretty thing to contemplate how long Kennedy, dropped into today's political culture, would last.)

Successful modern presidents, Cronin notes, are those who have best understood the need to serve "as a tribal leader . . . to govern by myth and legend and mystique and symbol" as well as by the more conventional tools of governmental persuasion.

At a time when the America tribe is doubting its exceptionalism and plainly worried about its future, the market for that kind of leadership seems ripe as ever.

Yet the nature of a presidential campaign process in a disillusioned time -- the undressing, the tearing down, the fascination with warts -- destroys myths rather than creates them.

Reagan broke through those barriers -- though not until he was already in office. The guess here is that by next November the voters will want another inspirational leader in that mold, one in whom they can invest hopes and fears, around whom they can once again wrap their own protective covering of faith. The question is: how do we get from here to there?

Paul Taylor covers national politics for The Washington Post.