The Reagan proposal for deep cuts in strategic nuclear weaponry deserves at least two cheers, plus a freeze on hostile comment until we see whether it is really negotiable. Tilted initially toward reducing Soviet advantages, and with a backdrop of rhetorical calls for a US strategic ''edge,'' START will at best be a long process.
The public debate on a nuclear freeze, with over two-thirds popular backing, will continue even as new ''bargaining chip'' weapon systems are built. But as debates go, it is badly flawed.
For the foreseeable future, we will be asked to choose strategic policy on the basis of irreconcilable assertions. Consider: the President's proposal is based on the premise of Soviet strategic superiority, which he argues a mutual nuclear freeze would codify.
But, until he said that, the nation's leading experts agreed that both sides are approximately equal. But the Soviets have in fact outbuilt the US in heavy missiles and payload, plus intermediate range SS-20s targeting Western Europe (and China).
But the US has more nuclear warheads and bombers, and better missile-firing submarines and unverifiable cruise missiles. But men now in high position theorize that Moscow could blackmail us.
But all Soviet and American leaders since Stalin have said no one could win a nuclear war. But both sides' technicians nevertheless plan for ''fighting'' a nuclear war if one should break out.
In short, extraordinary paradoxes, contradictions, and scary talk, all combining to jolt awake the sleeping giant of public opinion. It is likely to stay alert even as US policy starts back toward the mainstream.
It may help clear the mind to recall some fundamentals about weapons and Russians, without detailed numbers or jargon.
* With enough survivable delivery systems to ''make this rubble bounce,'' in Churchill's vivid phrase, what has changed to spark the current debate? Ten years ago there were enough nuclear weapons on both sides to incinerate us all - but no one paid much attention to them. What did change was that critics of the Nixon-Ford-Carter step-by-step arms control policies theorized that, with 300 large missiles permitted under SALT II, the Soviets could take out our 1,000 Minuteman land-based missiles, and follow with an ultimatum to give in or -- if we retaliated -- face destruction of our cities. Those critics are now in high office, and US strategy is premised on their theory.
Others who also realized that land-based missiles were becoming vulnerable nevertheless found the new theory incredible: (1) Soviet leaders could not be certain US missiles would not be fired on warning; (2) ample bombers, cruise missiles, and ships would be left to demolish Soviet industrial society; (3) if only one US submarine remained, it could destroy every major Soviet city; (4) no one knows who would give what orders in the chaos and terror of a nuclear attack; and (5) Soviet leaders are no more irrational or suicidal now than 10 years ago.
This grim equation of ''massive deterrence through massive uncertainty'' is ethically repugnant - and indispensable so long as nuclear weapons exist. It continues to make a first strike, regardless of who has what theoretical marginal ''edge,'' an act of total insanity.
* Can't the Soviets manipulate this mutual fear to their own advantage? Yes -- but. The Reagan administration (like the 1980 Carter administration) correctly perceived the need for repairing military weaknesses to convey clearer signals to the Kremlin about future Afghanistans. But if liberals tend to do too little homework on the Soviet system, the right wing does too much.
The USSR would take advantage if it could, but in cold fact it is the only country in the world surrounded by hostile communist powers. The view from Moscow is an amalgam of self-induced paranoia, an urge to exploit low-risk opportunities, awe of US technological superiority, fear of sneak attack, and determination never again to be militarily inferior to the US -- even after it has spent that trillion-and-a-half dollars. The Soviets resemble Bismarck who, when asked if he wanted war, replied ''Certainly not, what I want is victory.''
* How should leaders then respond to popular movements for nuclear freezes or cuts in specific weapons systems?
First of all, not as precise policy prescriptions. They are a metaphor which, translated, says to our leaders: ''Get back on the bipartisan track with serious , negotiable proposals that put the nuclear beast back in the cage, so we can all co-survive this conflict-prone century alongside a godless, pragmatic, unbluffable, advantage-seeking, war-fearing regime which (like us) would dearly love to save a buck (ruble) if it didn't look like weakness. Forget your theorists and offer a mutual freeze on new intercontinental nuclear systems until cuts can be negotiated. Cut warheads and land-based missiles now if you can get way with it, but to save time and money throw in bombers and cruise missiles now rather than later. With or without any of the above, get cracking on the real causes of war through prevention of local conflicts, building crisis-stable weapons, negotiation zones of superpower restraint, and improving communications with the Kremlin.''
And, if it helps make everyone feel better, rechristen the balance "Mutual Superiority."