Arms Control An Exercise in Trust

By BRUCE VAN VOORST WASHINGTON

Doveryai no proveryai, or "Trust but verify," was a favorite Reagan Administration phrase in the arms-control lexicon, but it is easier said than done. While nobody seriously proposes signing agreements that can be readily violated, opinions abound on what constitutes adequate proof that the other side is not cheating.

Last week it was learned that U.S. and Soviet negotiators in Geneva took a major step toward verification arrangements several weeks ago, when they agreed on inspection controls for the elimination of chemical weapons. American officials welcomed the accord as further evidence that after decades of failure, enormous progress is being made across the board on the thorny verification issues so central to all arms control.

A complete chemical-weapons ban may still be years in the making, but the inspection initiative is a promising sign of new thinking. Until 1987 the Soviet Union not only refused to let U.S. inspectors check compliance on the spot, calling it espionage, but also denied that the U.S.S.R. maintained any stocks of chemical weapons. Under the influence of glasnost, Moscow last week announced agreement in principle to on-site "surprise" inspections of facilities. The arrangement defines what sorts of installations would be involved and under what conditions an inspection could be demanded.

The Soviets have been accelerating their acceptance of such verification procedures since the 1987 INF treaty, which eliminated intermediate- and short-range nuclear missiles, set up procedures for monitoring their destruction. Soviet inspectors have been present in the U.S. during the demolition of 326 missiles, and Americans have witnessed the destruction of 1,088 Soviet missiles. More than two dozen Americans stationed permanently in Votkinsk, west of the Urals, keep tabs on a plant that once built SS-20 missiles, and a similar number of Soviets in Magna, Utah, monitor what was formerly a Pershing engine plant. Michael Krepon, a Washington arms-control expert, talks of "a degree of verification unthinkable just a couple of years ago."

Verification of an accord limiting strategic weapons (START) will be even more challenging. The INF category is comparatively simple to check. Since all missiles of a given type are to be destroyed, any such weapon spotted later would be in obvious violation. START will be far more complex. It will only reduce the numbers of various missiles, and inspectors will have to determine how many small cruise missiles are carried aboard bombers and possibly even submarines. Differentiation must be made between nuclear-tipped and conventionally armed cruise missiles, even if they look alike. A method will have to be found to keep track of mobile missiles. With all that, the supreme challenge will be how to prevent new production of banned weapons at secret locations.

Nor will it be easy to monitor proposed reductions in conventional forces in Europe. Thousands of armored vehicles and artillery pieces will have to be destroyed by NATO and the Warsaw Pact, and hundreds of thousands of troops demobilized or redeployed. The treaty language must precisely define differences between aircraft capable of carrying either conventional or nuclear warheads. Under previous verification standards, that task would be hopeless: satellite photography and electronic sensors are not sophisticated enough to count warheads on a missile or peer inside production plants.

Now the Soviets appear willing to accept increasingly intrusive inspections. To win U.S. ratification of the 1974 Threshold Test Ban Treaty -- still unapproved because of Senate doubts about verification -- the Soviets permitted American teams to monitor an underground test in Soviet Central Asia. In recent weeks Moscow has allowed Americans to inspect cruise missiles aboard a cruiser in the Black Sea and sanctioned a visit to the Sary Shagan complex, which the Pentagon had claimed, erroneously, housed an antisatellite laser.

The Bush Administration is ready to test growing Soviet openness further. Last month Washington proposed a START verification package to be negotiated and partly carried out even before a treaty is completed. The initiative suggests measures to count warheads on missiles, tag weapons at manufacturing plants and ban such impediments to verification as encryption of missile test radio signals during launches. "This isn't putting the cart before the horse," says Democratic Senator Sam Nunn of Georgia, "but putting them next to each other, where they belong."

In the end, even the most intrusive measures will not be foolproof: there is no verification catholicon. But perfect verification is as illusory as it is unnecessary. National security requires only that governments be able to detect militarily significant violations early enough so that they can do something about them. "Adequate" verification is indispensable to reducing the risks. Recent reports from the negotiating tables suggest that both the U.S. and the U.S.S.R. have awakened to that fact.

With reporting by John Kohan/Moscow