In public policy, propositions that are wholly right or wholly wrong are rare. The proposal to abandon SALT constraints, however, is a perfect specimen of the latter. It asks the administration to give up such areas of certainty as have survived the failures of the past; it proposes to bless whatever the Soviet Union might choose to do with its options wide open; and it proposes that this step be seen as a contribution to the negotiating effort the administration is making in Geneva.

Arguments based on personalities are usually to be avoided, but in this case, it is important to consider from whence this advice comes. It comes from those in the administration who have always believed that the SALT agreements are contrary to U.S. interests, and whose views would not have changed even had the record of Soviet compliance been without blemish. The arguments they offer now, though of substance, have not led them to some agonizing reappraisal, but to the threshold of their ultimate objective: dismantling the arms control process, which they regard as a "snare and a delusion" for the United States.

SALT II died as a legal instrument in 1981, when the administration formally notified the Soviet Union that the United States would not ratify it. All obligations under the SALT I Interim Agreement on Offensive Weapons had ceased to be binding in 1977, when that agreement lapsed. Nevertheless, both governments have undertaken to preserve segments of SALT I and II by avoiding actions that would undercut them. Not wanting to associate itself with SALT, the administration dubbed this reprieve the "No-Undercut Policy."

No-Undercut may appear to be at variance with the Reagan administration's view of SALT II as a fatally flawed document. Obviously, however, the administration found it unappealing to operate under conditions of complete uncertainty as to Soviet intentions. Hence, the willingness to enter an arrangement of convenience.

Until now, this has been an arrangement that profited the United States at no cost. SALT counting rules have required the Soviets to dismantle more than 1,000 launchers for strategic weapons, as they deployed more modern systems. To my knowledge, the United States has no declared quarrel with the Soviet Union over the number of these reductions or the manner in which they have been executed. We, meanwhile, have so far been required to take no such reductions; nor will we until September, when the sea trials of our seventh Trident submarine begin. At that time, however, we must decide whether to dismantle an aging Poseidon submarine, or 14 Minuteman silos, in order to remain in compliance.

Comes now a strong push from within the administration to reject this obligation permanently by throwing off the no-undercut regime or, as a fallback, by placing submarines in drydock rather than dismantling them. Arguments in favor of this course of action are: 1) SALT II would expire this December, even if it had been in force; 2) we should not accept a double standard by complying strictly with SALT dismantling requirements, when the Soviets are giving us trouble in other areas of the treaty; and 3) the Soviets are, in any event, a satisfied nuclear power and will not markedly increase the number of their weapons, even if the last vestige of SALT were done away with.

If the restraints that exist under the no-undercut policy are valuable to the United States, they should be continued regardless of the notional expiration date of SALT II. If Soviet compliance with the numerical sub-ceilings in SALT II has been satisfactory, we should make it a point to comply as well, rather than to toy with tit-for-tat violations that invite the unraveling of what is still working and still important. If the Soviets are satiated with nuclear weapons and can be counted upon not to begin a crash construction program, that should surprise those in the administration who have been obsesessed with Soviet capabilities to break out of the current constraints and suddenly proliferate the number of warheads they have. And, of course, it is the same people who cynically make both contradictory arguments.

Surely, it is madness to think that the United States should willingly give up all restraints on Soviet offensive weapons, in the teeth of their warning that the logical response to "Star Wars" is a Soviet buildup. Surely, it is clear that the SALT no-undercut policy is needed to preserve the foundation upon which both sides can ultimately erect a new agreement, if any agreement at all is in the cards. Surely, it should be understood that without such an agreement on offensive nuclear weapons, there is no future for the president's vision of a world in which defenses will have replaced offenses as the mainstay of deterrence. And that, surely, is the most important reason why the president should act with wisdom and reject the urgings of his zealots. Their victory means the defeat of his hopes . . . and the nation's.