A profound shift in military strategy in which the United States would renounce "first use" of atomic weapons if the Soviets attacked Western Europe with conventional forces was called for yesterday by four high-ranking former officials whose government service ranged from the Truman to the Carter administrations.

The United States has held out the first-use threat as a possible answer to the Soviets' decided numerical superiority in conventional forces in Europe.

The four officials argue that renunciation of first use not only would reduce the fear and likelihood of nuclear war, but would ultimately provide the basis for strengthening conventional forces and political unity within the western alliance, thereby improving the credibility of western defense and the ability to deter a Soviet attack.

The proposal to begin a "careful study" of such a strategy switch is in an article in the latest edition of Foreign Affairs quarterly.

The article was written by McGeorge Bundy, national security adviser to Presidents Kennedy and Johnson; Robert S. McNamara, secretary of defense in those same administrations; George F. Kennan, ambassador to the Soviet Union in 1952, and Gerard Smith, the chief delegate to the U.S.-Soviet strategic arms limitation treaty (SALT) talks under President Nixon and an ambassador-at-large in the Carter administration.

The four ex-officials presented their proposal at a crowded press conference here. Interest in it increased considerably after Secretary of State Alexander M. Haig Jr. in a speech Tuesday made a point of rejecting the idea, claiming that it would be tantamount to inviting Moscow to invade Western Europe.

McNamara said yesterday he regretted Haig's remarks. He said neither Haig nor his aides had actually read the article before Haig's speech and added that the proposal is not intended as an attack on this administration's policy. Rather, McNamara pointed out that the first-use policy has been in effect for some 30 years and had been supported by all administrations.

But McNamara argued that circumstances have changed and that a review of the strategy is now imperative. "I believe that sooner or later, if we continue to depend on a strategy that is founded on the first use of nuclear weapons, that deterrence will fail and western civilization, as we know it, will be destroyed," he said.

Kennan, asked if he felt either the Soviets or the United States would realistically refrain from using atomic weapons if they faced a defeat with conventional forces in Europe, said: "I can personally imagine no consequences of a defeat with conventional weapons which would compare with the disaster that is very probable to be unleashed if anybody started to use nuclear weapons."

When a questioner noted that McNamara, as a former defense secretary, had installed a lot of the nuclear weapons in Europe and asked what had changed, McNamara said there were some 6,000 such U.S. and Soviet weapons when he took office 21 years ago and today the combined stockpile is 50,000 and growing.

The United States and the Soviet Union both have thousands of intercontinental-range missiles based in their homelands. The United States, however, has not adopted what is called a "first strike" strategy for these continent-spanning weapons. Instead, U.S. policy has emphasized protection of these weapons so they could be used for retaliation against any Soviet first strike against this country.

But in Western Europe, where the Soviets have always had a substantial numerical superiority in ground troops and tanks, the United States and the other North Atlantic Treaty Organization countries have proclaimed a readiness to use smaller, shorter-range battlefield nuclear weapons first if there is ever a danger of being overrun by Soviet-led conventional forces.

Thus defense of Western Europe is a rare case in which U.S. and alliance nuclear policy is spelled out rather clearly, and the authors focus on that as the place where an atomic war could start that nobody could be certain of stopping.

The danger is that the first step across the nuclear threshold would start a reaction that would lead to full-scale atomic war. "I never met anyone who believed nuclear war could be limited," McNamara said.

One strength of the NATO policy, its supporters say, is the very ambiguity confronting Moscow about being met with atomic attack. But Bundy charged yesterday that, with the vast proliferation of atomic weapons now on both sides, "the value of that ambiguity is going down and the credibility of starting a nuclear war that could become so catastrophic is also going down."

The authors stress that they are not advocating that the United States pull its nuclear weapons out of Europe, though some could be withdrawn if the strategy were changed. They emphasize that atomic weapons would still be needed to retaliate against any nation that used them first.

The authors are not alone is calling for rejection of the "first use" strategy. Irving Kristol, a leading conservative intellectual and certified "hawk" on military matters, appealed for such a shift in an article in The Wall Street Journal in March. McNamara said that a number of former top military officers, including a former chief of the British defense staff and a former U.S. Pacific commander, Adm. Noel Gayler, have proposed similar shifts.

The four ex-officials argue that the profusion of these battlefield nuclear weapons "has made it more difficult than ever to construct rational plans for any first use of these weapons by anyone." In earlier decades, plans for use of such weapons were largely "hypothetical," and more recent efforts of the Ford and Carter administrations to improve deterrence through better planning only served to increase fears here and in Europe about nuclear war "and even of Americans as its possible initiators," they say.

To carry out a shift away from first use, however, the authors say it is crucial not to reduce NATO's overall deterrent power against Warsaw Pact forces nor to abandon the special relationship between the United States and West Germany.

To the authors, "it seems clear that the nations of the alliance together can provide whatever forces are needed, and within realistic budgetary constraints," and that the United States would also have to take on an "appropriate share" of whatever extra troops are needed to beef up the European front. They acknowledge, however, that it is "quite a different question whether the Europeans can summon the necessary political will."

Indeed, many European allies have been reluctant to add forces or spend heavily on defense despite U.S. pressure under the existing strategy. But the authors suggest that this may result in part from the nuclear shield over them. Thus, they assert that "if consensus is re-established on a military policy of no first-use that the people and the governments of the alliance can believe in, both political will and deterrent credibility will be reinforced."

The four officials also believe "there has been some tendency, over many years, to exaggerate the relative conventional strength of the U.S.S.R and to underestimate Soviet awareness of the enormous costs and risks of any form of aggression against NATO. Today, there is literally no one who really knows what would be needed."

Haig, in his effort to shoot down the proposal, suggested it would mean a return to the military draft .

The authors reject the idea of even a modified policy, under which the West might still strike first but only much later in a conflict than is now anticipated. "What the alliance needs most today is not the refinement of its nuclear options but a clear-cut decision to avoid them as long as others do," they state.

In raising the question of who should make the study they propose, the authors note that the issues raised by a no-first-use policy must inevitably be decided by governments. "But they can and should be considered by citizens," the authors say, suggesting a preference for a private group.

The authors show no special confidence in the Reagan administration at this point in handling such a matter. "The present American administration has so far shown little interest in questions of this sort, and indeed a seeming callousness in some quarters in Washington toward nuclear dangers may be partly responsible for some of the recent unrest in Europe," they say.

Nevertheless, the authors observe that all their administrations "revised their early thoughts on nuclear weapons policy."