IN PARIS, 40 years ago, I met a modest man who was going to become the foremost European of our era. He was motivated by a breathtakingly simple idea: putting an end, once and for all, to more than century-old Franco-German hostility.

His name was Jean Monnet. I encountered his deep passion one day in the summer of 1948, when he invited me to join him for lunch.

After questioning me methodically about my two recent visits to West Germany as a correspondent for Le Monde, he asked me to look at the wall on my left where a very large map of Europe was displayed. He had circled France and Germany. Then he disclosed calmly the true object of the lunch:

"You see, our problem is to avoid, this time, the pitfalls of all previous occasions. How can we create an ambitious, but realistic, pattern by which France and Germany would cease, once and for all, to be eternal enemies and made to be partners in a common venture?"

"If we solve this century-old fatal flaw, we should be able to advance on a whole new range of world problems. But this one, at the heart of Europe, has to come first. If not -- Europe will remain divided, weak, and on the way to its final decadence . . . ."

Monnet was gazing constantly at the map, that circle, these two eternal enemies, a torrent of blood, it seemed, between them: the River Rhine.

What he was looking for, this public-policy manager, this trans-national mind, was nothing less than the key to a miracle . . . . I sat in silence, knowing how right he was.

I made some remarks, in a mood of approval and encouragement. And it went on until he started scribbling notes on a pad in front of him. Before I left he mentioned that he would probably draft a short memo on some intuition that had come to him during the discussion.

Monnet did indeed put his draft of a solution to the problem of France and Germany in a memo of three short, hand-written pages. This was the outline of what came to be known as the "Monnet Plan."

He stated his bold innovation in the simplest language: "The basic instruments of war between our two great countries have been made from the resources, in coal and iron, of both France and Germany, on the borders of the Rhine River. The recurrent inevitability of war will not be reversed by nice feelings or good speeches. Let us go to the very root of things and propose that France and Germany put all their steel-making capacities in one common pool, governed by one common authority. This supra-national agency will be controlled by a common board chosen by both parliaments, with its own executives. No part, whatsoever, of French or German coal mining or steel making capacities should remain outside the control of this new, and common, High Authority."

The sequence of events that followed is well known. The "Coal-Steel Pool" was created and implemented. One by one, the other concerned nations -- Italy, Belgium, Holland, Luxemburg -- joined this first, basic, pact. It became "the six-nation Community."

And then, year after year, they decided together, following the pool's logic, to enlarge the concept and the authority, giving birth to the European Common Market, then the European Economic Community.The movement, reversing centuries of history, had become irreversible.

This episode, the birth of a new Europe, shows the extent of the consequences due to the clarity of one mind, at the right moment. Can it be an inspiration for our new, larger challenges of today? We shall see in a moment.

If difficult decisions were required for the complex construction of Europe, they were dwarfed by the one public-policy problem of historical dimension: how, for all of us, to accept and manage the end of the colonial era for western civilization, the end of our control of so many, and such large western-dominated countries in Asia and the Pacific, Africa and the Indian ocean, Latin America and the South Atlantic. And one single name became the symbol of it all, then and now: Vietnam.

The man who understood that problem earliest -- with the same audacious simplicity that Monnet applied to Europe -- was Pierre Mendes-France, the French prime minister in the mid-1950s. I was then his junior aide.

His finest hour came after the disaster the French defeat at Dien-Bien-Phu. Mendes-France had to extricate, with honor and a reasonable cease-fire, a large part of the French Army.

Before going to the peace conference in Geneva in the summer of 1954, Mendes-France had to find a way to change radically the terms of the encounter, which would be disastrous for us: One fifth of the French military force in Vietnam had been crushed in the battle of Dien-Bien-Phu. We had to face defeat, pure and simple, and still try to negotiate a decent peace settlement.

Today, the same delicate question is still with us all: How to avoid, or abandon, positions of precarious military domination without creating a chain of disorders both in the far-distant countries involved and in the psyches of our own people.

One evening, before the peace meeting, the staff was working on various diplomatic options. Taking me into another room, Mendes-France, refusing to be pressured either by the heavy machine of State or by the infinite international rules of protocol, told me in simple terms his essential intuition.

"We must find a completely different way. If, in the comfort of habits, we start negotiating, in classical terms, all the issues of such a complicated peace, one by one, two disasters will become inevitable. First, it will be endless. They can drag on for months and even more. Second: during this terrible cascade of protracted negotiations, we shall get into deeper and deeper military involvement. In the end there will be nothing to negotiate; only to abandon. So enemy No. 1, right now, is time. Time is against us. Think about it."

I came back to him with a simple suggestion: Refuse to be dragged into endless negotiations by giving the opponent, although victorious, an ultimatum. The peace agreement, on the essentials, must be signed in one month. Mendes-France should announce, in advance, that he would resign as prime minister, and send to Vietnam massive reinforcements and maximum air-power to be at the disposal of the next prime minister.

And that was it. Parliament could do nothing but approve; it did without dissent. At the end of one month, on the very eve of the deadline, peace was made. And never again, from that day, after more than a century of colonial rule, would any French force return to Vietnam.

If only the American officials had been able to act as decisively when their turn, unfortunately, came in Vietnam. But to them, simple answers to Vietnam never seemed possible. I discovered this very early in the story, during a 1962 visit to Washington at the invitation of John Kennedy.

My host was extremely cordial, and displayed his famous open-mindedness by mentioning a range of subjects he suggested we could discuss, today and tomorrow -- and then asked me, kindly, in what order did I prefer. I took a deep breath and gambled on the intelligence of the man. I told him that I thought my duty would be to propose to talk about one topic, and one only. Then the deep breath: Vietnam.

He showed total surprise and disbelief. He mentioned the continuous tension with the Soviets since the Cuban crisis. He mentioned the expansionist potential of Communist China. He continued with the sensitive question of the balance of forces in Europe, and specifically the necessary, if ominous, rearming of Germany

That was the end of 1962. And on the surface Vietnam, indeed, was nowhere a flashing red-light in the war-rooms of the world. But having gone through this agony ourselves, we in Paris knew that a really explosive danger lay in the shadowy, covert escalation of the American military expedition into the well-known, to us, swamps of Vietnam. We imagined with horror the profound consequences of this new "march of folly," following our own path, leading also to final humiliation and defeat -- only in much larger dimension, both in the world and at home.

I reported that to John Kennedy, as the simple message of my visit.

He listened, at first in total disbelief, then with decent interest. He called Defense Secretary Robert McNamara and made an appointment for me the next day. The session with Secretary McNamara, to my surprise, was quite disappointing. Alarmingly so. After listening with care he summarized his disagreement: "You see, it is not conceivable that an American force in Vietnam would meet, as you imagine, the sad fate of the French army. It is not a question of bravery but of technology. We have something your generals did not have and left them so vulnerable: thousands of helicopters. We can saturate the skies in Vietnam, if we happen to be so overwhelmed."

I returned to Kennedy with increased fears. He showed clearly that he was less than reassured. He then asked his brother Robert to monitor this problem, and to keep in touch with me in Paris. But then came Dallas. Lyndon Johnson felt the joy of being a commander-in-chief in the pursuit of military "victory." The rest is history.

A vision, today as yesterday, is nothing, only a nice dream, unless it is supported by a coherent prospect for implementing it.

Such was the radically innovative and very simple plan by Jean Monnet that built Europe. Such wasthe remarkable Marshall Plan. Such was Mendes-France's making of peace in Vietnam in 30 days. Such was JFK's simplest and most effective of all plans, in all ways: To light the flameof youth, giving it a real appetite, a joyful impetus, to create and master the future.

Taking our world as it is now, more diverse and complicated than at any of these previous periods, we must decide that the plan for the future will be most likely to be understood and made to work if it is of utmost simplicity.

So, I shall conclude with two simple suggestions.

The hostile relationship between the two Americas -- the intellectual and the military -- must cease, at all cost.

There is no basis for conflict. American defense will rest on America's brain-power. No more, no less.

When the Soviets gave Syria their most modern land-to-air SAM missiles to cancel the superiority of the Israeli Air Force, what did the Israelis do? They took state-of-the-art computer technology, and trained their pilots, day and night. On the screens of flight-simulators the pilots reviewed again and again the whole Beka Valley, along the border of Syria, from all angles, at all hours of the day. It was real innovation -- and an act of faith in science and education, in knowledge as the supreme resource.

On the day of the raid, more than the Israeli squadron was at stake. Their target was nothing less than the capability of the Warsaw Pact itself against the latest in western computing art and excellence in human expertise. In 35 minutes all of the SAM batteries lay destroyed deep into the ground. All of the computerized fighter-bombs had returned to their base; the universe of the military, around the planet, had changed.

We have to assume that the Russians too have come to the same conclusion: True security is higher knowledge. Very far from the blind, and ruinous, accumulation of sterile hardware.

This, of course, fits their vital need to rebuild their obsolete economy by transferring a very large portion of resources and brains, monopolized by the military, to the creative part of the Soviet society, along with the massive, continuous buildup of the learning system at all ages. "New knowledge is now the only source of true economic power," says Richard Cyert, president of Carnegie Mellon. And true security.

From this common need could come the birth of an Era.

Because it points to a most natural partnership, the Soviet-American hostility into an joint competition of trained brains in the common Knowledge Revolution that is transforming the world economy: A battle that could make the old dogmas of the cold war pale into insignificance.

Two simple ideas for 1988. Impractical, unrealistic? That was what people said to Monnet and Mendes-France.

Jean-Jacques Servan-Schreiber is chairman of the International Committee of Carnegie Mellon University and a former cabinet member of the French government.