Some day some kind soul may introduce the president of the United States to his secretary of defense. Then Ronald Reagan and Caspar Weinberger might meet for a long, candid talk about national security and public opinion.

Then, maybe, they could avoid doing what they did last week. That is, expressing early opposite opinions in early simultaneous speeches on matters crucial to the development of a credible national strategy.

The president gave his speech to the Military Academy at West Point May 27. The thrust of his argument was that there had taken place, with his election, a fundamental change in the national attitude toward defense.

Reagan started with the immediate past. "We have," he said, "been through a period in which it seemed that we, the people, had forgotten that government is a convenience of for and by the people." During that period, he went on, "government neglected one of its prime responsibilities, national security, as it engaged more and more in social experimentation. Our margin of safety in an increasingly hostile world was allowed to diminish. . . . There was a widespread lack of respect for the uniform, born perhaps of what has been called the Vietnam syndrome."

But presto, chango. Now, according to the president, "The American people have recovered from what can only be called a temporary aberration. There is a spiritual revival going on in this country. . . . The era of self-doubt is over."

The secretary of defense gave his speech to the Air Force Academy in Colorado Springs the same day. Like the president, Weinberger started with the election. "Last fall," he said, "the voice of the American people clearly demanded that our nation be second to none in military power. . . ." But Weinberger made no claims for a total change in national mood. On the contrary, he pointed up the responsibilities incumbent on those in the defense establishment, and particularly the military, to behave in ways that did not undo a transformation that he acknowledged to be "fragile." He said:

"We, more than any of the other 200 million Americans, hold in our hands and in our daily work the potential to fortify or erode the public consensus in favor of a stronger defense. If we are perceived as wasteful or unreceptive to new ideas of strategy or tactics, or if we do anything to lose the people's confidence, we might destroy the fragile national consensus so recently formed for stronger defenses, and the new national resolve to fight if necessary for our future."

It is possible the president is correct in asserting that there has already taken place an irreversible change, stigmatizing what happened after Vietnam as "mere aberration." Possible, but not likely. For all the evidence goes with the more somber view set forward by Weinberger.

The attitudes associated with Vietnam were not, like a plague, something foreign that came, went, and is now gone forever. Far from being an abnormality the so-called "Vietnam syndrome" was a logical response to a misbegotten war in which many, including many military men and at least one commander in chief, behaved ignobly.

The anti-military lobby -- "the shrill voices," as the president called them -- has been muted but not silenced. Witness the way most of us in the media went bananas about the dispatch of half a hundred American military men to El Salvador. Witness, too, the anti-defense writings of James Fallows in the Atlantic magazine and of Prof. Lester Thurow in the New York Review of Books.

Skepticism about the utility of force, moreover, is not something confined to the United States at a special time. It is a condition native to advanced countries in the modern era. Hence the survival of the nuclear allergy in Japan; and the virtual destruction of the navy in Britain; and the recent Dutch vote against the stationing of nuclear weapons in Holland; and the swing, on the nuclear weapons issue, against Chancellor Helmut Schmidt in West Germany; and the drift, by the new Mitterrand government in France, away from the assertion of military power in the Third World.

If this view is even slightly correct, the president does the country no service by pretending that one election and the right slogans service to put the country back on the safe, sound road to security. The secretary of defense is more right in emphasizing the fragility of the present consensus, and the responsibility of the Pentagon to develop new approaches to strategy and tactics.

Indeed, the true test of a credible strategy in foreign eyes is apt to depend on the willingness of Americans to pay the blood tax -- national conscription. But the secretary of defense did not bother to mention the matter. And the president dismissed a peacetime draft as "counter to American tradition."