If the message of ''The Day After'' is that arms reductions will inevitably increase national security, then the nation has been sadly misled. Of course, fewer bombs would be nice and certainly less expensive. But even the optimistic proposal of a 50 percent cut in our nuclear arsenals would leave enough megatons to destroy civilization as we know it.
What we ought to be looking at are the triggers not the bullets. The next time one side or the other begins a countdown to fire a torpedo, an air-to-air missile or an ICBM, we must have tested ways of saying ''stop'' to all the parties involved. At a minimum, the people who make the minute-by-minute decisions in both countries need to be able to talk to each other - and talk fast. A 20-year-old hotline is a primitive and inadequate tool.
The threats we face are complicated by the spread of weapons of unprecedented leverage and lethality. Where the threats of the weak, the criminal, or the crazy could once be dismissed, today such threats could be the first step toward Armageddon. There are few, if any, means to prevent a single incident from snowballing into a cataclysmic series of events. Management of such crises need not be purely ad hoc - a great deal can be done in advance to discourage knee-jerk, ideological, or trigger-happy responses.
We need to develop jointly with the Soviet Union new techniques of command, control, and communications that could disentangle the superpowers once tensions begin to rise. While confidence-building measures, such as advance warning of NATO or Warsaw Pact exercises, have become a normal part of the diplomatic discourse in this and previous administrations, reliance on the existing consultative mechanisms clearly does not always work. Whatever substantive judgments Messrs. Andropov and Reagan might have reached, for example, about the Korean jetliner become irrelevant in the face of a rigidly based Soviet military decision to act - a decision almost certainly taken at the middle level of the military command structure.
The downing of that jetliner makes clear that the national command authorities on both sides must be linked, at more than just a political level, if we are to pursue a crisis-management option intelligently. We need to be able to determine the basic military and political issues involved, to identify the critical decision points affecting the participants, to know what decisions are made at what levels, and how to contain violence on the heels of confrontation.
One institutional mechanism to begin discussions about crisis-control techniques is the Standing Consultative Commission, a permanent body of military and intelligence professionals from both sides which takes up alleged treaty infringements and, so far, has dealt effectively with all the challenges to treaty compliance by both sides. Would it not be equally reasonable for such a body to consider the kinds of joint efforts that result in mutual advantages rather than in recrimination? Ultimately such an effort will require sophisticated analytical modeling, as well as computational and teleconferencing capabilities, to deal with the technical aspects of the problem. The International Institute of Applied Systems Analysis in Vienna, directed by both American and Soviet scientists, could be a meeting ground for future study.
The risks of sharing data in these kinds of joint simulations should not be ignored. In attempting to understand the dynamics of each other's decisionmaking process, the danger that the Soviets might be deceitful enough to hide their true command structure - and their intentions - cannot be dismissed. The root question, however, is whether the strategic gains from such exercises would well outweigh the potential for tactical losses - and we will never know the answer if we never try. We must make the attempt, or we most certainly will run the risk of blundering into situations that may make the Korean airliner tragedy appear minor by comparison.
What is clear is that traditional means of arms control have accomplished very little. What is equally clear is that present efforts at crisis control are wholly inadequate. The problems have become too complex and the dangers too imminent to be left either in the hands of the diplomats or the defense planners alone.
A hundred years ago, it took months to deliver a declaration of war, much less to mobilize the men and supplies needed to fight it. The technology was such that small military units were capable of inflicting relatively small damage. Today, small numbers of unsophisticated, angry people can travel the globe in the span of a day; can communicate with others almost instantaneously; can carry sophisticated weapons of disproportionate lethality; and, unless we are very careful, can drive the superpowers and the rest of the world into a conflagration from which humankind cannot escape.