MOSCOW — Soviet leader Mikhail S. Gorbachev's decision to back away from a summit meeting with President Reagan may not halt progress toward a second agreement to slash strategic nuclear arsenals on both sides, a senior American official said Saturday.
Gorbachev's unexpected refusal to set a summit date ended two days of Soviet-American talks on a sour note despite near-agreement on a treaty to eliminate intermediate nuclear forces worldwide.
Appraising the results of Secretary of State George P. Shultz's lengthy talks with Gorbachev on Friday, the official, a top U.S. diplomat, said that summits are not as essential as many people think.
"If we don't get a summit--so what?" asked the official. "This is healthy, since it shows we have a long way to go. . . . This (Soviet-American) relationship is a long slog." The official, who asked not to be named so he could speak with greater candor, said it looked less likely than it did a month ago that Gorbachev would come to Washington this year.
While the Kremlin chief said several times during his talk with Shultz that he would like to visit the United States, his refusal to set a date means that "time is getting short," the official said.
"If he thinks we're going to change our position to get him to come, he's mistaken; we're not," the diplomat said.
"We had every reason to believe that if we wrapped up the INF (intermediate nuclear force) treaty, they would set a (summit) date," he noted.
Both Shultz and Soviet Foreign Minister Eduard A. Shevardnadze said that a treaty abolishing missiles with ranges of 300 to 3,000 miles could be concluded by experts in Geneva within two weeks.
At one time, both sides had anticipated that Gorbachev and Reagan would sign it in a ceremony in Washington, marking the first time that the Soviet Union and the United States had ever agreed on an actual reduction in their nuclear stockpiles.
The medium- and shorter-range weapons lumped together in the intermediate category account for 5% of the total nuclear warheads possessed by the two superpowers.
As a result of two days of Moscow discussions, agreement on the treaty is complete except for "a few dots on the i's and crossing of t's," an American participant said.
The official said that a second treaty--to reduce long-range, strategic nuclear weapons by as much as 50%--is within reach and could be concluded by next spring, if the Soviet Union does not continue to insist on linking it to restrictions on U.S. research on a space-based missile defense system.
Originally, Reagan and Gorbachev were to sign such a second treaty during a presidential visit to Moscow in the first three months of 1988, the official said, but that timetable is now much more uncertain than it was.
Soviet negotiators have pressed for changes in the 1972 Anti-Ballistic Missile Treaty to limit U.S. research and testing of Reagan's Strategic Defense Initiative, popularly termed "Star Wars." If the Soviets are trying to cripple SDI by revising the treaty, the American official said, that would be unacceptable. But if they merely want to limit the amount of "unpredictability" on its prospective deployment, that could be negotiated, he added.
Gorbachev, declaring his reluctance to go to the United States this year without an advance agreement on key provisions of a treaty dealing with strategic offensive missiles and space defenses, was quoted by the official Tass news agency as saying:
"I hope 1 1/2 months are enough to work out and duly prepare all of this. I am ready to visit the United States. But so far, I am put on my guard by possible results."
When Gorbachev said he would not set a date for a summit, despite the virtual completion of work on the intermediate forces pact, Shultz said he could not guarantee that an agreement would be possible on "Star Wars" limitations.
"So be it," one participant in the meeting quoted Shultz as telling Gorbachev. "You're still welcome to visit."