NO SINGLE program engaging the United States and the Soviet Union has lost more altitude in recent years than strategic arms control. The sense of peril that long drove talks has faded. Political easing has cut deeply into the anxiety and competitiveness that fueled arms building. Tight budgets have forced unilateral decisions on reducing or forgoing the weapons that otherwise would have been regulated by treaty. No longer is arms control the high-policy arena, the pacemaker and temperature setter of superpower relations.

Yet as long as the two countries retain nuclear weapons of colossal destructive power they have a grave obligation to hold them and reduce them in ways that promote safety and stability. On the experience and example of Soviet-American arms control, moreover, all efforts to limit the arms of others rest. Arms control has a residual value that goes far beyond housekeeping.

This is the context in which to weigh the uncertain status of the Strategic Arms Reduction Treaty (START). Its negotiation began almost a decade ago, or, depending on how you count, two decades ago: in another age, another world. Its goals, which once seemed momentous and practically beyond achieving, now seem almost minimal. At the moment, some think, it may be less urgent to reduce Soviet strategic arms than to make sure that the kinds and numbers retained are kept in the grip of a strong and responsible government -- something that the current Soviet flux has called into question.

This flux has added its own burden to negotiation of a START treaty. Just as the republics are no longer dutifully responsive to the central union, so the ministries are also champing. This seems to be why the Soviet Foreign Ministry -- an island of perestroika -- is having trouble delivering the military, or the general staff, to a treaty. Open civilian-military tension over arms control is not unheard of elsewhere. It seems to be popping out in Moscow as part of an overall challenge to reform. The signs are evident in erratic Soviet compliance with the already-signed treaty for reducing conventional forces in Europe (CFE) as well as in the lagging pace of talks on START -- talks now meant to be completed for a Bush-Gorbachev summit in the spring.

These are long-fought, hard-bargained treaties -- not the stuff of dramatic triumph but serious business. The world is not such a sure and safe place that Americans or Soviets can just as well do without them -- or without further arms control, bruised, oversold and maligned a process as it is. Those in the Soviet Union who would toy with either START or CFE are truly reckless.