Gorbachev Acts to Spur Arms Pact : Diplomacy: He agrees to send his foreign minister and army chief of staff to Washington for talks. Move could clear the way for a summit.

Soviet President Mikhail S. Gorbachev, responding to an appeal from President Bush, agreed Monday to send his foreign minister and army chief of staff to Washington this week to try to settle a festering arms control dispute and clear the way for a summit meeting before the end of this month.

Soviet Foreign Minister Alexander A. Bessmertnykh and Gen. Mikhail A. Moiseyev, chief of the general staff, will arrive in Washington late Wednesday for talks Thursday and Friday with U.S. arms control negotiators led by Secretary of State James A. Baker III, the White House announced.

“It’s a good thing that they’re coming, and . . . there’s plenty of time to get this done so we can have a (summit) meeting at the end of July,” Bush told reporters.

In a weekend message to Gorbachev, Bush asked the Soviet leader to send Bessmertnykh and other negotiators to Washington.

Moiseyev’s presence on the delegation seems to substantiate U.S. concerns that the Soviet military has assumed a much more prominent role in arms control matters. However, Administration officials said they are relieved that Moiseyev is coming because Moscow’s civilian bargainers recently have lacked authority to make major decisions.

“We are pleased that (Moiseyev) is a part of the team because we think that’s important, that they have the military leadership as a part of the negotiating team,” White House Press Secretary Marlin Fitzwater said.

Negotiators long ago completed most of the text of the complex Strategic Arms Reduction Treaty, which would cut the long-range nuclear arsenals of both superpowers by more than one-third. But they have been hung up for months on three technical issues that Administration officials consider critical to ensure Soviet compliance with the treaty terms. At the same time, U.S. officials say that the Soviet military may be seeking an opportunity to revise previously approved sections of the pact to reduce the number of weapons that Moscow will have to destroy.

Bush emphasized that he expects U.S. and Soviet negotiators to complete work on the treaty before he sets a date for his visit to Moscow. The President and Gorbachev want to sign the pact at the planned summit.

“We want to have a summit meeting with the Soviets . . . and their (Bessmertnykh and Moiseyev) coming in here is a good move,” Bush said. “Whether these last difficulties can be ironed out, we just don’t know. But this should be seen as a good sign, whether we get it completed in time for a July summit or not.”

Bush and Gorbachev already have agreed to a two-hour working lunch in London on July 17 after the economic summit meeting of major industrialized democracies. Gorbachev expects to outline his plans for Soviet economic reform to the leaders of the United States, Britain, Germany, Japan, France, Italy and Canada.

Presumably, Bush and Gorbachev could address pressing issues during their London talks, reducing the pressure for an early Bush trip to Moscow. Nevertheless, the two leaders agreed last year to conduct a full-dress U.S.-Soviet summit meeting in the first half of 1991, a target that they already have missed, and they are reluctant to let the schedule slip much more. Both Bush and Gorbachev plan vacations in August, so if they do not meet this month, they would be unable to do so before September.

Fitzwater said that the Administration is pushing for a July summit to “keep the pressure on . . . to push to do it (the strategic arms treaty) as fast as we can.” But he said that Washington does not plan to give in on treaty issues just to clear the way for a summer summit.

Responding to complaints from Moscow that the United States is driving a very hard bargain on the arms treaty because it believes that the economically strapped Soviet Union ultimately will have little choice but to go along, Fitzwater said that both sides have shown flexibility so far.

“We have interests that we believe are crucial to the strategic well-being of the United States, and we are not going to sacrifice those interests,” Fitzwater said. “On the other hand, we have made many changes in our position. . . . We would prefer to think that we have been flexible and the Soviets have been flexible. We just need a little more flexibility.”

Although Fitzwater denied that the Administration has made an arms agreement a quid pro quo for U.S. economic assistance, he said that both arms control and economic cooperation are “all part of the East-West relations quotient.”

“They are aware and we are aware of the arms control interests that the United States has,” Fitzwater said. “Indeed, as you judge the Western interest in promoting (economic) growth and reform in the Soviet Union, a reduction in arms has to be one of the major benefits that we get out of that.”

The Issues That Are Stopping START According to the State Department, these are the three main controversies standing in the way of a START agreement. New Types:

The treaty will prohibit either country from developing ICBMS as large as Moscow’s current SS-18. It will permit existing weapons to be modernized. Moscow plans to modernize its SS-18s, but Washington maintains that the result will be a new weapon and therefore prohibited. The dispute is over defining how new a weapon must be to be classed as a new type.

Downloading:

The treaty will limit the number of warheads each nation can deploy. The Soviets want to remove some warheads from existing missiles (for instance, turning a three-warhead missile into a single-warhead missile). The United States wants counting rules that assume all missiles carry the maximum number of warheads whether they actually have that many or not. Washington’s rationale is that the Soviet plan would not require Moscow to destroy as many of its existing missiles to get down to the warhead limit. If the Soviets decided to renounce the treaty and build up their arsenal, they would simply have to restore the maximum number of warheads to each missile.

Data Denial:

Under the treaty, each side is supposed to know what the other is doing with long-range nuclear weapons. The United States accuses the Soviets of coding missile test data and wants to ensure that coding is effectively banned.