THE complexities of conventional arms control far exceed those of strategic or intermediate-range missile negotiations. They confront a host of problems: Not just the nuclear superpowers but all members of the two opposed alliances must be factored in and their consent obtained to any agreements.
Not five or 10 weapons systems but hundreds of different kinds are at issue, including not just tanks and planes but their counterpoints: antitank and antiaircraft missiles.
Each item raises definitional problems. Force estimates made by the Warsaw Treaty Organization (WTO) include naval forces that the West prefers to sidestep. This helps explain why WTO estimates for NATO personnel and aircraft are higher than the West's. NATO contends that the naval forces should not be counted, because they might be redeployed elsewhere. But so long as they can hover within range of the Soviet Union, they are highly relevant to Warsaw Pact calculations.
Even the WTO numbers understate NATO's advantages at sea. The Western navies have far greater experience than the pact's. They are not boxed in by ``choke points,'' such as the Turkish Straits; they have true aircraft carriers vastly more powerful than the helicopter and vertical-takeoff carriers in the Soviet Navy; their technology is more dependable.
If the Warsaw Pact bargains hard, it will ask for quid-pro-quo reductions in Western naval strength to offset the asymmetrical cuts in WTO tanks and other land assets.
Asymmetries are anchored in geographical and other peculiarities of each side. Thus, the United States needs huge armadas to reach across oceans; the USSR needs large armies to defend its long borders. Washington has prosperous and stable allies; the Kremlin has impoverished and unstable vessels.
Indeed, the greatest imponderable in the whole equation is morale: Should East European forces be counted with or against the USSR? Romania has not permitted Warsaw Pact maneuvers on its soil since 1956. East German generals might be loyal to Moscow under some scenarios, but what of ordinary soldiers and citizens? Even the loyalty of the USSR's border republics is in doubt - certainly in the Baltic states and probably the Ukraine and Byelorussia as well. The USSR has only 40,000 troops in Poland, but they man vital logistical and communication routes. If communist rule falters in Poland, how many Soviet troops would be needed to intimidate the Polish people and armed forces?
Mikhail Gorbachev may reason that his policies make the East Europeans more dependable as they warm to the appeals of perestroika. But this is a risk. As Russia's imperial will slackens and Soviet forces recede, Eastern Europe will probably experience a tide of rising expectations eroding all communist institutions.
Mr. Gorbachev's glasnost has extended to the military sphere - opening the Krasnoyarsk radar and chemical warfare facilities to Western observers. In January it made another giant step: The WTO defense ministers published their estimates of the conventional balance of power in Europe - from the Atlantic to the Urals. The WTO data contained many surprises. For example, they showed higher numbers of tanks and multiple-launch rocket systems for both alliances than comparable Western studies. They also showed the importance - from an Eastern perspective - of naval strength. Most important, the WTO data put some numbers on the table to be compared with other estimates.
Comparison shows substantial disagreement not only between East and West, but also among various Western estimates. NATO's estimates of combat aircraft and helicopters, for example, differ substantially from those of the Pentagon, even though both proceed from the same data base. The International Institute for Strategic Studies (IISS), a nongovernmental research agency in London, publishes quite different numbers from NATO and the Pentagon, even though the IISS depends heavily on Western intelligence estimates. The independent Stockholm International Peace Research Institute and the Institute for Defense and Disarmament Studies in Boston also count things differently.
So long as the experts disagree on what is, they will have trouble negotiating what should be. Percentage cuts make no sense unless all parties agree on the base line. Even reductions to absolute levels are difficult without consensus on the starting point. Unless we know how many tanks or missiles are to be junked, verification will be impossible.
The issue of tanks illustrates the difficulties. Both alliances this year have endorsed a common ceiling of 20,000 tanks for each side. Even by WTO estimates, this entails a reduction of over half the pact's tanks - a tremendous concession. The New York Times published a chart on May 30 showing that the pact estimates NATO tank strength at 30,690, while the NATO count for its tanks is 22,224.
The Times chart actually uses the IISS estimate, for NATO calculates Western tanks at only 16,424 - below the 20,000 ceiling - and the Pentagon at 25,900. Which number is correct? If the pact is right, NATO must cut its tanks by one-third; if the Pentagon, a cut of one-fifth is required; if the IISS, one-tenth. But if NATO headquarters is correct, the West may increase its tanks by almost one-fourth and still comply with the 20,000 ceiling!
WHY do estimates range so broadly? Some differences are honest reflections of inherent complexities; some are deliberately deceptive, inflating one side and minimizing the other. For years, NATO has cried ``wolf'' (or ``bear'') to rally funds and enthusiasm for the common defense. It has understated Western assets even though this distortion added unnecessarily to East-bloc bargaining leverage. Such distortions could be seen as treasonous, since they wasted the enormous investments already made and promoted defeatism. Even today the Pentagon's estimates exclude France and Portugal from NATO totals, though France in the past decade has rejoined NATO planning and maneuvers.
Tank estimates also vary because it is difficult to know what forces to include and how to weigh them. Should old tanks be listed with new ones? Light tanks with heavy? Active duty tanks with those in storage? Similar questions buffet every category of forces: Should reserve units be counted even though they would take some time to mobilize? If US forces are located (or relocated) thousands of miles across the ocean, how to compare them with Soviet forces just beyond the Urals? How to evaluate antitank missiles against tanks if modern tanks acquire better armor or if missiles become more accurate?
Tradeoffs are an old problem. How many tanks to give up for how many planes or ships? Gorbachev is willing to cut back on tanks and other weapons that could be used for a blitzkrieg against the West. But the West retains its own weapons that could be used offensively. By WTO count the West has 50 percent more attack aircraft than the East; not only does NATO have more such planes, they have a longer range and can carry heavier payloads than Soviet models; even the nonnuclear members of NATO, such as Italy and Germany, have dual-capable planes able to carry nuclear arms. Only recently has George Bush offered to put these assets on the bargaining table.
Despite these and other complications, arms control in Europe looks more promising than at any time since NATO's founding 40 years ago. Preparedness has paid off. Because Europe has become the most heavily armed region of the world, no rational planner could even dream of attack. Now the trick is to maintain stability while reducing the explosive power and military outlays on which it has been built.
TECHNOLOGY and interdependence make arms verification easier as the world becomes more transparent. But it is the human factor - attitudinal change - that makes serious arms control more feasible than before. Soviet glasnost - openness - is both cause and result of changing perceptions. Moscow no longer wants to intimidate Europe and it no longer fears the West. Indeed, some Soviet arms specialists say they no longer object to German unification, because German militarism cannot rise again. Having mastered the scientific-technological revolution, Germany has no need to bully its neighbors or acquire more territory.
Fighting wars is more expensive than ever, but so is the cost of readiness. The Soviet bear has seen that every time it growls, the West steps up its arms and cohesion. The Gorbachev Politburo concludes that a tough line is counterproductive, because Russia needs friendly trading partners in the West - not frosty foes.
Gorbachev asserts that ``security must be mutual.'' He sees that the USSR cannot be secure if Soviet forces make others feel insecure. Gorbachev accepts symmetrical cuts reducing some Soviet advantages as in intermediate- and shorter-range missiles.
Old difficulties remain; new ones will probably emerge. Where there's a strong will, ways can be found to circumvent the complexities. Realism requires an appreciation of the obstacles as well as the advantages to arms limitation.