We are coming up for a series of Vietnam anniversaries. It will soon be 10 years to the day since this decision and that debacle, since all those searing television tableaux; people clutching at departing helicopters, Saigon withdrawn behind closed shutters into unimaginable fright, the arrival in America of planeload after planeload of silent, stupefied Asian children.

I don't know how these events will be commemorated. But I suspect that in some degree we will re-enact the conflict. I don't mean one of those fife-and-drum re-enactments we do to commemorate our distant and (to us) painless past, but rather a re-enactment of the searing political conflict that took place here at home.

America's commitment and its performance will be reargued. Individuals' positions on both will be rejustified. And there will be much talk of "lessons" learned. But what will be most obvious is that very little has been learned, that 10 years later we are still thinking and talking about the events as if this were 1975. Those who were against this country's engagement will have managed to ignore or rationalize away the implications for their position of what has happened since in Indochina. Those who favored engagement will use those terrible subsequent events as retroactive justification for war policies that were profoundly flawed.

This is classic American time-warp politics. We have not figured out a way to remember a momentous national experience without simply reliving it, being intellectually immobilized by it, admitting no further evidence whatever that might alter our understanding of what happened and what it meant. I'm not suggesting forgetting here, only letting in new information and insights, acknowledging changes in the landscape and changes in our own understanding, so that we can get the good of our experience.

In a sense Vietnam and Watergate -- they go as a single entry, are often spoken as a single word -- are very like two earlier American traumas, the Great Depression and World War II. I don't mean they had anything substantive in common. What they had in common was the intensity and consequence of their impact on a generation. For great numbers of people who came of age in the early decades of this century, the Depression and the war became and remained the central experiences against which all else was measured. For some of the most articulate and politically active, the years of battle over the New Deal were a time of deep personal commitment, excitement, combat, exhilaration and risk. And the struggle that preceded American entry into the war had much the same character.

I am thinking of people on both sides of those political disputes. They were formed by them. And many continued to reargue them in relation to every new situation that arose long after they had lost their immediacy and relevance. Well into the '50s and '60s and even '70s, American politics was impeded and to some extent deformed by politicians trying either to repeal the essential, permanent social advances of the New Deal or -- on the other side -- to create new programs in its image that were not appropriate to utterly changed circumstance. On the war issue, the argument went on over whether we even needed to have gotten into the hostilities and whether our government had not helped bring them about (the right wing was the "blame America" school then). People saw postwar "Munichs" everywhere. They tended to re-create their past, not to use it or add to it or learn from it. As a result some helped to impose obsolete, wrong policies on government and on the political parties decades later. Ten years later, where do we stand on the question of Vietnam? What does the word itself connote to us? Study the news and you will see a perfect split-screen situation. In New York there has been a libel trial -- General Westmoreland vs. CBS -- in which the 10-year-old domestic argument about our involvement was replayed. In Indochina itself there is horrendous suffering, much repression and a protracted and virulent war among our former adversaries and some of our onetime friends.

Many of the people concerned with the issues raised by the first of these news events seem utterly oblivious of and indifferent to the issues raised by the second. These are people for whom the assault on American Vietnam policy or the defense of it was the central, formative political experience, the apex of engagement and energy, the episode against which all else is measured now. The miserable Indochina of 1985 is used only as a prop in their restaged drama, as supporting evidence for premises that it should, instead, challenge.

A couple of years ago I asked a politician o had been a leading force in the effort to get the United States out of Vietnam and a pre-eminent arguer of the case that "our side" was worse than "theirs" whether he had been surprised by the brutality of the victors. He said: "I never thought they were angels," and that was all. It was not just defensive, but also, I thought, inadequate on the part of one with a claim to moral sensibility. His other response, like that of many, has been to overstate greatly the degree of our responsibility for the ugly turn of events in Indochina since we left.

That is one way of dealing with the reality of Indochina now. Another, no better it seems to me, is that of the retroactive vindicators, those who claim the persecution and bloodshed rife in that part of the world now show that we could, with enough bullets and will, have done the job and should have. Should have, maybe, but could have I truly doubt. I think the turmoil shows the situation was harder than we thought, not easier.

We have two sets of I-told-you-so's in a conflict that with the passage of each day, not to mention decade, gets more irrelevant. God knows the subject is critically relevant to the way we think about our involvements abroad now and to the necessity of reconsidering our ideas about such involvement. But too many people, so far as I can see, are blinded and tyrannized by their memory of the experience, and refuse to take its illumination. They are unwilling to reinspect what happened and what is happening because that means reinspecting and perhaps reappraising their own past role and belief. This too will cost us dear -- Vietnam seems able to exact no end of revenge.