THERE WAS SUCH an outpouring of good feeling at the recent dedication of the Vietnam veterans' memorial that it is tempting simply to leave matters as they are. Let those who were twice victims, over there and back home, finally be embraced by their countrymen. Let the families of dead children finally see their sacrifice fully recognized. Touch the names cut into granite, share in the tears.

But it would do no real honor to the Vietnam veterans to confuse their personal and deserved catharsis with the sort of genuine national catharsis we have never had. The Vietnam monster has not been buried under those granite panels on the mall. It is still hiding under the rug, where we stashed it years ago.

You can prove that by asking a 20-year-old of your acquaintance what he or she knows about the war, remembering that today's 20- year-olds were 6 at the time of the Tet offensive. As a rule they know almost nothing about Vietnam, because most of their elders have not bothered to teach them anything.

Hiding it does not disguise what the war in Vietnam really was: a terrible betrayal of the American people by their elected rulers. Starting from a fundamental misconception of America's national interests, the politicians who have the power to do such things sent 57,939 young Americans to Vietnam to die, thousands more to be maimed, and hundreds of thousands more to be scarred by deep, invisible wounds.

This was horrible enough, but it was by no means the sum of the damage done to America. Vietnam tore up the social compact between governed and governors in this country. It showed millions of Americans that the governors could do incredibly stupid things without paying any great price. It showed that the rulers marched to a drummer all their own -- could turn the other cheek when thousands of young men had to die for the sake of an "honorable peace," as Richard Nixon and Henry Kissinger described their Vietnam objective. By that they meant a cease-fire and American withdrawal not immediately followed by a communist victory. In pursuit of that lofty goal, nearly 20,000 Americans died after Nixon took office with his "secret plan" to end the war.

Looking back at the '60s and '70s now, we seem to have jumbled together Vietnam, urban riots, campus chaos, assasinations, generation gaps and Watergate, as if those years were just a bad time full of bad events.

But most of those bad events had common origins -- in Vietnam. The war was one of those great motors that change the course of history. It wasn't just bad luck, a bad hand drawn from a god-given deck. We did it ourselves, retaining our freedom of action as we marched ever deeper into the slime.

It is striking that no one in command in those years has ever really been held fully responsible for what happened. Oh, Lyndon Johnson was driven from office, the "best and the brightest" got some bad publicity, even Gen. William Westmoreland has been put in an unflattering light. But there has never been a formal national accounting.

Many of the perpetrators carry on in public careers as if nothing much happened. Walt W. Rostow, who peddled good news from the battlefield like snake oil, is honorably employed today; so is McGeorge Bundy, who played such a key role in drawing us into the conflict; so is Dean Rusk, who kept justifying it on the basis of a Chinese threat that never materialized.

This is not to suggest that such men were grand conspirators who realized from the start how their individual errors contributed to the horrible whole; little happens in Washington that is so deliberate or coordinated. Nor does it mean these men should have been drawn and quartered; many of them obviously recognize that they erred. For example, after leaving the Pentagon where he had done so much to design the war, Robert S. McNamara spent years working to better the lot of the world's poor in the World Bank. That looked like an act of penitence.

The point is that virtually the entire American establishment rallied round those who had led us into this tragedy -- not by embracing them, but by absolving them. In the process, the establishment protected itself. By evading any final settling of accounts, the loose grouping of influential people that passes for an American ruling class avoided the sort of profound challenge it had earned for allowing Vietnam to happen. And that has allowed the establishmnent to go on being the establishment. Business pretty much as usual.

Vietnam was wrong. It was fought on a false premise (remember the domino theory?) against an enemy who wasn't there (what happened to the Chinese-Vietnamese cabal?). The war taught a generation of Americans to distrust its leaders, destroyed the great postwar prosperity, poisoned America's reputation in the world, and contributed mightily to a deterioration of true American national security, not least by devastating a military budget that might otherwise have been spent sensibly to deal with a genuine Soviet danger.

This happened largely because a succession of American politicians, poisoned by the venom of Joseph McCarthy -- and long supported by many editorialists, including those for this newspaper -- felt they had to keep proving their anti-communist vigilance in Vietnam. It was probably as simple as that. Neither Kennedy nor Johnson nor Nixon would take responsibility for what finally happened anyway. In the end they found it easier to live with a war that killed 57,939 Americans than with the accusation that they hadn't been tough.

So what? So we now have a sick country. Our politics is flat and sterile, and few Americans turn to government to solve what they consider major problems. Voter turnouts for our elections -- which ought to alarm moreeAmericans than they do -- started to tumble during the war. The belief that our leaders lie and scheme to our own detriment was richly nourished by Vietnam, and cynicism is now a grave national disease. A fat upper class has what appears to in a stronger position than ever to manage the country for its own benefit.

None of this is very appetizing. But more important, in a genuine democracy, which America continues to be, none of it is likely to last. There will be some kind of reckoning.

Already the public has reacted by electing two successive amateurs to the White House. We shouldn't be surprised if some day a gifted demagogue comes along who can reach the substantial majority of Americans who now don't participate in our politics. With the help of a good demagogue, the American people may turn on the people who gave them Vietnam and its fruits. If they do it will be an ugly moment.

It used to be easy to argue that this is such a blessed and lucky country that really awful things -- a demagogue in the White House, say -- just aren't possible. But the war in Vietnam could not have happened to a blessed, lucky country. Lady luck ran out on us when we tried to take her into the rice paddies and highlands of Indochina, and she hasn't been seen since.