HOW CAN WE end the Indochina war?

By having the greatness to admit national error, the intelligence to act on that admission, and the compassion to do it quickly.

To put the matter bluntly: in some wars there is simply no substitute for failure.

By this I mean that every effort to avert acceptance of error and failure-every "cosmetic" approach, in current Washington parlance-is simply a formula for further evason and self-deception and for a longer, wider war. Every effort to "save face" will lead to new Cambodia's, renewed bombing of the North or bizarre high-risk speculation, like the abortive prisoner-rescue effort.

For any President who thinks he can exist with grace from this twenty-year error is a President who, when confronted with the possibility of the look of defeat-resurgence of the Communists, collapse of "Vietnamization"-will balk and grope for new "protective reaction," new flexing of the muscle, new acts of bravado, new targets of opportunity, new military adventure, up to and including, I deeply fear, the threat of the use of tactical nuclear weapons. There will always exist, waiting in the wings as an anguished President frets, persuasive peddlers of new ways to "win" this unwinnable war.

What we do desperately need is something no President has had the courage to face and to tell the American people: that Vietnam was "lost" many years ago, by the French, by the Americans, and mostly by Vietnamese; that nothing short of perpetual war might "retrieve" that loss (and at what cost!); that the loss doesn't matter in terms of American security interests and indeed has never mattered; and that an admission of error and failure that brings peace to a shattered region is far from "national humiliation," as Mr. Nixon once called it.

What would be the results of such a message from the Presidency?

We have most of us dealt with the young on the campuses today-either our children or our students-and we probably share the same mixed view of their undoubted ability, their stupid and dangerous excesses, and their sometimes prophetic vision. On their side, though, is time. They will, in fact, inherit the earth, or at least our chunk of it; they will, in fact, soon vote. And they would, undoubtedly, give allegiance to a President who did what I have just suggested. So would many of their compatriots in our restless Indochina armed forces. And so would the millions of the not-so-young.

YET we have also been warned, for as long as I served in Government and now by those in the Nixon Administration, of the "right-wing backlash," the new "loss of China" witch-hunt, that would follow such a move. We have been warned of the headlong flight into "isolationism," or "neo-isolationism" that would ensue. Are these real dangers?

The first, a "backlash," seems probable in some form in the wage of virtually any outcome short of "victory." It is simply a fact of life: the inescapable price open societies must pay for righting a major and prolonged wrong. But it is also very clearly containable in the present instance-thanks largely to the overwhelming agenda of things to be done at home and elsewhere in the world, thanks also to the media that have brought is war's insanity into every living-room, thanks hopefully to effective executive leadership.

As for the second danger-"isolationism"-it seems highly improbable. We have been over-invested, over-committed, overextended in parts of the world, and particularly in East Asia, over the past twenty years. But disinvestment in one area, and indeed, pullback in Asia, cannot in this day and age mean anything like what those who grew up in the twenties and thirties so much fear. We are simply too globally involved, through communications, technology, trade, travel, economic investment, diplomacy, and our special status as a nuclear power, to return to anything resembling the dream of Fortress America.

This is not to suggest that the formula I offer will have easy consequences-for there is, of course, no easy way out of our present Southeast Asian crisis. But it can, under the right leadership, move us gradually toward something new and precious: a tempering of our national grandiosity, an end to our special sense of benevolence as a nation-an erosion of the ugly qualities that accompany such overweening confidence, including excessive fear of "loss" or "failure." It can lead, in time, toward a new national maturity: a sense that we are only one of many, and that we cannot transform the world by ourselves.

And it can lead, in the process, to a new degree of candor in our Government's relations with its own citizens and in a new degree of respect by the citizens for their government. We can thereby begin to cleanse ourselves of the war's most debilitating poison: collective deception and national self-deception.

IN HIS televised interview of January 4, President Nixon was asked what he would do if our "Vietnamized" Saigon allies were to falter in the course of American withdrawal. His reply: "... I am simply not going to borrow trouble by saying I expect them to fail. I don't think they will."

In such delusions, such refusals to look ahead, such shrinking from the lessons of the past, is rooted a quarter century of Indochina tragedy.

( This article appeared in the New York Times of Saturday, January 16. Professor Thomson teaches in the History Department. )