Next Arms-Cut Talks: Whole New Challenge : Military: With the Soviet threat gone, experts see more complex and dangerous scenarios.

With the conclusion of the second Strategic Arms Reduction Treaty, known as START II, American arms experts are looking beyond the accord to a new, more challenging and potentially more dangerous era in arms control.

President Bush and Russian President Boris N. Yeltsin may be signing a treaty that will cut U.S. and former Soviet nuclear arsenals to their lowest level since the early 1960s. But arms control in the 1990s and beyond, experts say, will make negotiating with the old Soviet Union look like the easy part.

In arms control’s new era, the United States will negotiate not with one partner but with many. All of them will have divergent interests, although few will be avowed adversaries of the United States, as the Soviet Union once was. These new negotiating partners will be seeking not to cut a seemingly endless arsenal of weapons but to thwart the emergence of terrifying new arsenals before they are fully developed.

On the other hand, many of the nations that nurture hopes for such arsenals will not be sitting at the negotiating table. And many of the agreements struck will be limited in value because they will lack mechanisms to ensure enforcement.

Such changes have prompted some experts to proclaim an end to arms control itself--or at least to the treaty-producing process the world has come to know.

“Arms control seems to me no longer relevant,” said Richard N. Perle, an arms control expert in the Ronald Reagan Administration. “The doctrine of arms control we’ve experienced grew up precisely in the Cold War context, and it was aimed at moderating and affecting the behavior of countries that identified themselves as adversaries.”

Now, Perle added, “we’re talking about a community of nations trying to affect each other’s behavior, and the whole theory is different. Here, we’re not talking about detailed arms accords; we’re talking about (countries agreeing to) very broad principles. And we’re talking about a world without verification of these agreements. So we’d be advised to look to more traditional diplomatic techniques to solve problems as they arise rather than to look to arms control treaties.”

Since the dawn of nuclear arms control, the ink on arms treaties has barely been allowed to dry before legions of American and Soviet negotiators were again dispatched to Geneva or Vienna to begin work on the next arms accord.

During the Cold War, when negotiating teams regularly huddled for years before producing a treaty, a quick return to the table underscored not only the complexity of cutting superpower arsenals but the importance of the negotiating process itself in an age of nuclear standoff between the superpowers.

Since the Cold War’s end, negotiators have had to return quickly to the table just to keep up with the breathless pace of political developments.

But now, the superpower negotiating rooms of Vienna and Geneva are expected to lie empty for some time. There is no immediate talk of START III, a negotiation to cut weapons below 3,000 warheads.

“The need to have another (round of) negotiations for central strategy weapons is relatively low for the next year,” said Edward L. Warner, a senior arms control analyst with the RAND Corp. “I don’t think pressure to go lower in numbers is the dominant question at this time.”

Instead, President-elect Bill Clinton will inherit a welter of arms control priorities that have both greater urgency and less promise of producing treaties than previous negotiations.

All of them will be multinational negotiations, like the talks to renew the 1970 Non-Proliferation Treaty, which expires in 1995. Some, like START II and the International Chemical Weapons Convention, which countries may start subscribing to early in 1993, are accords that were largely negotiated during the Cold War and will require the cooperative efforts of many nations to implement.

Others, like the effort to negotiate a Comprehensive Nuclear Test Ban, have grown out of Cold War weapons programs but live on in a world where countries that are not enemies--France, China, Russia and the United States--continue to dispute the usefulness of an agreement.

“Arms control has become more complicated,” said Michael Krepon, co-director of the Henry L. Stimson Center think tank and an expert on arms negotiations. “It was always complicated, but it’s more complicated now. Russia is in conflict with itself on arms and other issues, and you have more players at the table. The multilateral nature of the beast has grown.”

Indeed, the implementation of the START II agreement, which will fall to the Clinton Administration, says much about the difficulties the United States will have in this new world of multilateral arms control. The reductions required by the new treaty cannot be carried out until not only Russia but Kazakhstan, Belarus and Ukraine--all of which still bear Soviet nuclear weapons on their soil--have ratified START I and become signatories to the Non-Proliferation Treaty.

Kazakhstan, Belarus and Ukraine all said last year that they would give up their nuclear weapons and leave Russia as the only former Soviet state with nuclear weapons.

Ukrainian officials have assured Washington that their Parliament would ratify START I this year. But Ukraine has so far delayed doing so, and Belarus is waiting for Ukraine to move before ratifying the treaty. The United States, meanwhile, has said it would not begin to implement the START I treaty--and therefore cannot proceed to implement the START II treaty--until all those countries have ratified START I.

“You have a very confused situation in Russia and the entire Soviet Union,” Krepon said. “In the old days, you could still work bilateral deals. But nowadays, even bilateral deals have third-party complications. And within the republics of the former Soviet Union, instead of collusion between Soviet military and political officials, you now have both camps divided within and between themselves.”

According to Warner and Perle, such complexities will put pressure on the United States to declare unilateral arms control deals and either hope or ensure unilaterally that others follow suit.

Warner predicted that efforts to dismantle and destroy nuclear weapons material in the wake of START II will likewise be by U.S. decrees, not formal treaties.

That path will be particularly important, said Perle, in the renegotiation of the Non-Proliferation Treaty, an accord that many suspected nuclear weapons developers have not signed.

“We don’t want the Libyans, North Koreans and Iraqis to acquire nuclear weapons, but we’re unlikely to negotiate with them about that, and to the degree we do, we’re going to be wasting our time,” said Perle. “The main avenue for preventing proliferation is going to be action aimed at restraining the proliferaters with such mechanisms as export controls, intelligence operations aimed at disrupting programs and, ultimately, perhaps even the use of force.”