FEW developments so epitomized the promise of a new Soviet-American relationship during the heady years of the Gorbachev reform phase as the progress toward completing the ambitious nuclear and conventional arms accords known as START and CFE. Even as recently as last November, when NATO and Warsaw Pact representatives met in Paris to sign the landmark conventional-forces agreement, the presumption was that this was just the first in a likely succession of treaties that would codify the cold war's end and sweep both sides' arsenals clean of their lethal and costly excesses. But like mounting storm clouds on a once limitless horizon, recent events only tangentially related to the issues at hand now obscure this once certain future, imperiling the completion of both treaties. The indefinite postponement of the February summit between Presidents Gorbachev and Bush is both a symptom of a possible sea change and a potential source of threat to forward momentum in the United States-Soviet relationship. Canceled ostensibly because the START treaty was not yet ready for signing, the Moscow summit was more likely one of the costliest casualties of the two leaders' singular preoccupations of the moment. Obsessed with the fates of two of the world's smallest nations, Kuwait and Lithuania, the world's two largest superpowers could not take the time to deal with the destiny of the world's most important relationship - with each other. As is always the case in arms negotiations, the issues in dispute are highly technical in their details but highly political in their essence. The more contentious of the two treaties at this point is the conventional-arms accord. Soviet negotiators are now insisting that three of their motorized infantry divisions originally thought to be included in the treaty should be exempted because the Soviets reclassified them as naval shore-defense units. US, Western European, and Eastern European negotiators all insist that the Soviet argument is without merit and that if left to stand, it would create a giant loophole in the treaty. Some observers speculate that the sudden emergence of this dispute signals the growing influence of the Soviet military here as elsewhere in the Gorbachev regime. ``Life after Shevardnadze,'' Lee Feinstein, assistant director of the Arms Control Association, calls it, though he cautions against exaggerating the change. ``In the endgame of negotiations, both sides' militaries become more prominent. But at the highest levels the Soviet military still supports both treaties, and the Soviet foreign ministry realizes their enormous political significance.'' In order to settle the dispute, however, President Gorbachev may need to overrule some of his own generals. Strategic-arms negotiations are stalled on more technical grounds involving data exchanges and other arcane issues. On these matters, most observers believe both sides have reasonable cases. ``It's a political problem,'' says John Isaacs of the Council for a Livable World. ``With the high-level attention of the secretary of state and Soviet foreign minister, it could be resolved fairly quickly. But neither is giving it that attention at the moment.'' Though the two treaties are technically separate, they are politically wedded, and START would likely find tough going in Congress if CFE, which has already been signed, remains unresolved. Next to the immense military and political significance of these two treaties, the issues in dispute are absurdly small. In actual numbers, the conventional-arms dispute involves just 3,500 of more than 70,000 weapons covered by the treaty. Yet further delays in resolving these issues could render both treaties hostage to the vagaries of unrelated political events in the Middle East and the Baltics. Soviet resistance to US war aims in Kuwait or renewed measures by Moscow to assert its control in Vilnius could easily lead to demands from congressional hawks to ``punish'' the Soviets by freezing arms negotiations. ``There is a danger that these treaties will be held hostage to immature tendencies in the American political system,'' says Jonathan Dean, for many years the chief US negotiator at the Mutual Balanced Force Reduction (MBFR) talks that preceded the current CFE negotiations. ``We need to learn to anesthetize ourselves to unrelated events.'' Moreover, we would only be punishing ourselves by scuttling these treaties, for in exacting lopsided reductions on the Soviet side, they dramatically favor the West and redress long-standing imbalances in the military relationship. The prospect of prolonged civil unrest in a disintegrating Soviet internal empire and the alarming possibility that some of its nuclear weapons and other armaments could fall into ``unauthorized'' hands make it all the more imperative that an international system of constraints and limitations be instituted now, while there is still a central authority in Moscow with which to negotiate. -PATHNAME- /usr/local/etc/httpd/plweb/DBGROUPS/paper/database/tape/91/mar/week10/esomm.