OF what use is President Reagan's Strategic Defense Initiative? That depends on whether we actually develop it or trade it away in the arms control process. Actually trying to build ``star wars'' seems a mistake. I was recently involved with a project of the Public Agenda Foundation to explore our national options on the nuclear defense issue. My job was to interview the experts across the political spectrum, to explore their ideas in depth. One of the few points on which there was a semblance of consensus among them was that the hopes for an effective star-wars defense were based on illusion.
Nothing approaching meaningful protection, they said, is technically possible. It won't work, I was told, because thousands of incoming warheads could even now overwhelm it; because penetration by even a fraction of those thousands would inflict catastrophic damage; because such weapons as cruise missiles can slip under the defense; and because the 20 years between now and conceivable deployment would allow offensive systems to develop many more ways to elude the defense.
Another grave problem, of concern to many, is that developing star wars would destabilize deterrence. Deterrence is stable when neither side can rationally calculate it to be advantageous to strike first, either in confidence, believing it can get away with it, or in desperation, believing that otherwise it will itself be the victim of a disabling first strike.
Star wars is destabilizing because it introduces uncertainty about the future structure of deterrence; because it destroys one of the principal achievements of the arms control process (the ABM treaty); because heightened anxieties about retaliatory capability would accelerate the arms race in offensive weapon systems; and because two such systems overlapping in space would each have the capacity to destroy the other virtually instantaneously, thus providing an incentive to pull the trigger first.
To get these dubious benefits, moreover, we would be paying a staggering amount of money. If star wars is of little use to build, it seems to have a lot of value as a bargaining chip. The Soviets seem genuinely afraid of it.
If American experts think it will not protect us, why are the Soviets nervous?
Soviet planners feel a responsibility to make worst-case assumptions about both American capabilities and intentions. American planners made similar assumptions about the Soviets in concocting the implausible ``window of vulnerability'' scenarios a few years ago. Even if the Soviets can see that it probably won't work, they worry ``What if it does?'' Also, since the system makes more sense as a shield against a smaller retaliatory strike, the Soviets will impute to us the worst of motives, j ust as the United States has done for Soviet land-based missiles that threaten American silos.
Which brings us to the bargain that can be struck. This bad American idea, star wars, can be used to cancel a bad Soviet idea, the emphasis in the Soviet nuclear arsenal on land-based missiles. Theirs is a bad idea because it is also destabilizing. Land-based missiles, because of their accuracy, are the weapons best suited for launching a first strike; and because they are stationary, they are also most vulnerable to a first strike. Trading two bad ideas is a good idea.
Reagan, at a recent news conference, would seem to rule out making such a deal. Perhaps this is not to be taken at face value. The more credible our intention to develop a system, the more value it has as a bargaining chip; conversely, the Soviets will not give up much to prevent a system from being constructed that we have no desire to build anyway.
But if the President is bluffing, he is doing it most convincingly. Whether or not the Soviets are convinced, his performance indicates to domestic observers that he believes that we can become invulnerable through the miracle of American technology. A tendency to wishful thinking has been repeatedly noted by observers of Mr. Reagan's presidency: whether it be the disappearance of apartheid or his strong support for supply-side economics, the President shows a capacity to believe what he wants to believ e regardless of evidence or argument to the contrary.
The prevention of nuclear war is, however, too important for wishful thinking. Deterrence, as Churchill said of democracy, may be an unsatisfactory regime, but it is the best of the alternatives. So the experts almost unanimously told me, and so we must hope the men around the President will tell him.
History has entered an age where national security must be based on common security. The arms race represents a competitive approach to security that no longer serves; the survival of our species now depends on cooperation, such as in the arms control process now stalled and endangered in Geneva.
Andrew Bard Schmookler, a consultant, is the author of ``The Parable of the Times: The Problem of Power in Social Evolution.''