I suppose one must yield, or at least defer in some way, to the great weight of argument and opinion against the so-called "Buck Rogers" section of the president's speech on defense and nuclear arms. This is the part in which he recommends a stepped-up effort to find technologies for defending against nuclear weapons, for disarming them or rendering them useless.

What's wrong with this seemingly reasonable proposal? Just about everything, to judge from the immediate reaction of scientists and strategic planners. For one thing, they say, the technology isn't even close to being at hand--so it is probably just a pipe dream. For another, even though Reagan said this quest for a nuclear defense was not intended to supplant the pursuit of negotiated arms reductions in the meantime, many people feel that precisely such a falling away of arms-control effort would occur. And even if it didn't (the argument continues), the prospect of our unilaterally achieving a capacity to defuse or disarm strategic nuclear weapons would so threaten the Soviet Union that God knows what it might be frightened into doing before our defenses were perfected--not to mention what we might be emboldened to do if our project succeeded and we had, in effect, a kind of nuclear monopoly once again. The spirit, if not the letter, of the anti-ABM agreement would be violated, we hear. War in space would be all but guaranteed. And, if all this is not enough, the provenance of the proposal in the first place is suspect: its originators and leading advocates are very right-wing, very anti- arms-control guys.

All right, all right--no mere columnizer could hope to take on all this. Even we aren't that arrogant or foolhardy. So I surrender. But I do not intend to go quietly. My parting yelp comes down to this: whatever the merits of the individual objections being raised, I sense too great a piling-on here, too immediate and total a springing to the defense of old and--I should have thought--at least somewhat questionable ideas. Maybe nuclear stability would be threatened by the president's initiative. But certainly nuclear orthodoxy has been threatened by his enunciation of it. What we are learning is that a remarkable constituency has grown up around the idea that we and the Russians can hope for no better than a prolongation of the old balance-of-terror politics: guaranteed mutual vulnerability to nuclear annihilation, this vulnerability to be carefully nurtured and maintained until such time as agreements are reached to restrain and/or reduce and/or finally--this is the hope--eliminate nuclear weapons.

I have spent a certain number of hours in my lifetime arguing with my more disarmament- minded friends that the balance of terror has had its indisputable and indispensable uses. But as one who believes this hideous doctrine has, in fact, over the years, had the practical effect of helping to deter nuclear war, I still don't think of it as representing either the most or the best that is possible by way of preventing nuclear incineration. Does anyone? And I have argued, too, that, fearsome as it is, the situation on which it is premised (each side's remaining a hostage to utter destruction by the other) is less dangerous than the strategic alternative in which each side attempts to fortify and defend itself and develop a war-fighting capacity. But I am still made uncomfortable by the implications of the preferred, mutual-hostage strategy. Aren't you? Can anyone feel intellectually or morally content with a position that requires us all to assert, as a matter of national policy, that we are willing to obliterate millions upon millions of innocent, helpless human beings and cause others unimaginable suffering for any cause whatever?

At a purely practical level this particular strategy has had its evident peacekeeping value, mainly by two-way intimidation. But it is becoming impractical now. Its logic has marched ahead, unimpeded, toward an obvious end of the line, and its momentum has driven us all--I include the Soviets in this--to a wholly lunatic place. The grotesque numbers of deployed nuclear weapons and their monstrous explosive potential are testimony to this. The almost comic saga of our own MX missile tells the same story. We and the Soviets are both committed to building bigger and bigger and better and better in order to neutralize the other's advantage. And in doing so we have gotten in the position of those overarmored knights in the late Middle Ages, who managed mainly, by the end, to immobilize themselves: one fall and they couldn't get up. Over time, the steel crossbow, the longbow, the cannon got them.

Many people now recognize the end-of-the- line quality of our nuclear assumptions. Perhaps we can't create a large, invulnerable, MX- type land-based missile. Perhaps we have to go to something else. Surely we have to think imaginatively, radically, unencumbered about this. There are alternatives: going to sea with our strategic weapons; creating smaller, lighter, more mobile ones; reaching agreements with the Russians (and others) to control these weapons, to reverse the growth of our arsenals.

But I really cannot see how the record concerning any of these alternatives suggests that it alone is the right course or that it would, if pursued to the exclusion of all else, necessarily lead to a good outcome. In particular, there is a sense in which our arms agreements seem invariably to lead to greater armament: each government can get the assent of its military only by pledging to go ahead with the most formidable and lethal weapons allowed under the agreement's terms. And our history of simplifying and rationalizing our cumbersome nuclear arsenal isn't by itself wholly reassuring, either.

It is an astonishment to me that 14 years after our own first landing on the Moon, and in an age habituated to mind-boggling scientific achievement--including 15-minute lead time to rocket-borne nuclear destruction--"Buck Rogers" and "Star Wars" should be dismissive terms of ridicule for a proposal such as Reagan's. Maybe it really is no good; I don't know. But is no such initiative worthy? Is it unfit for contemplation? Historically, invention has succumbed to other invention, science has bested science. I wish the status quo nuclear gang would try to improve on Reagan's thought, not merely satirize it. I wish they, too, would think radically.