WASHINGTON — Achieving what Soviet leader Mikhail S. Gorbachev called a "breakthrough" on the long-divisive issue of anti-missile defenses, the third summit meeting between the Soviet leader and President Reagan ended Thursday by living up to its high expectations in arms control--greatly advancing prospects that a treaty slashing strategic weapons will be completed in time for a Reagan visit to Moscow next spring.
But the Soviets held fast on other areas of dispute between the superpowers, denying President Reagan any visible success on such issues as Afghanistan and the plight of Soviet Jews. Gorbachev refused to set a final date for withdrawing 115,000 Soviet troops from Afghanistan and told Reagan he cannot preach to the Kremlin on human rights.
Thus, while making most of the concessions on arms issues, the Kremlin chief persevered in refusing to allow arms control to appear to be linked to Soviet behavior in the Third World or to what he considers internal matters such as Jewish emigration--areas in which he may have been most vulnerable to criticism from his detractors at home.
The Carter Administration, for example, had followed a strict linkage policy, withdrawing the second strategic arms limitation treaty from the Senate in 1979 after the Soviets invaded Afghanistan. And the Reagan Administration had sought to exert similar pressure.
Gorbachev may pull Soviet troops out of Afghanistan next year, as the Kremlin has hinted, and perhaps even begin the withdrawal before Reagan travels to Moscow. He may also continue to let the rate of Jewish emigration rise--it is now almost 10 times higher than last year, but still far below the high levels of earlier years. But Gorbachev has made it clear he will not do so under direct U.S. pressure.
Despite these differences, the close of the summit signaled that "a new situation is emerging in the world," as Secretary of State George P. Shultz said. The new agreements on arms control, now the cornerstone of U.S.-Soviet relations, permit an improved political climate between the superpowers.
"We need a realistic understanding of each other's intentions and objectives, a process for dealing with differences in a practical and straightforward manner," Reagan said in his statement bidding Gorbachev goodby. "As a result of this summit, the framework for building such a relationship has been strengthened."
Gorbachev said in reply that, thanks to the summit, "we have been able to formulate a kind of agenda for joint efforts in the future. This puts the dialogue between our two countries on a more predictable footing and is undoubtedly constructive." U.S.-Soviet relations are entering "a new phase," he added, and "we can talk about a deepening political dialogue."
Thursday began overcast and rainy, with gloomy comments by officials suggesting the summit would end in an anticlimax. Diplomatically cold words such as businesslike , straightforward , and frank were used to describe the two leaders' final meeting.
Statement Indicates Progress
But the joint statement ending the summit, coupled with interviews with senior Administration officials afterward, made it clear that in fact great progress had been made.
The language in the final statement, which caused the final Reagan-Gorbachev session to be delayed 90 minutes, showed a startling degree of convergence on key arms issues.
Most important was missile defenses and their relation to cuts in strategic offensive weapons, the most powerful and dangerous elements in U.S. and Soviet nuclear arsenals. Earlier, the two sides had agreed to slash their offensive arsenals of long-range missiles and bombers by about 50%--to 1,600 "delivery vehicles" carrying a total of 6,000 warheads.
The Soviets had insisted, however, that they could not cut their offensive forces without some curb on the the Strategic Defense Initiative (SDI), the anti-missile program popularly known as "Star Wars."
After failing to win concessions through direct assaults, in recent months, the Soviets had sought such constraints indirectly--through the 1972 Anti-Ballistic Missile (ABM) Treaty, which forbids deployment of missile defenses except around one site in each country.
Before the summit, U.S. and Soviet negotiators had agreed to consider extending the non-withdrawal clause of the ABM treaty for a given period of time. But three major differences remained: how long the period would be; what kind of research, development and testing, if any, would be permitted during that period under terms of the treaty; and what would happen at the end of the period.
The length of the period was viewed as a relatively minor issue. The Soviets wanted 10 years, while the United States offered until the end of 1994. At the summit, Reagan and Gorbachev discussed the matter, and while they came to no firm agreement on it, neither side believes it will be difficult to arrive at a compromise, a senior U.S. official said.
Points of Accord Listed