Not so long ago, American policy-makers would be concerned about the forth

coming Sino-Soviet summit, the first one in 30 years. But that's no longer the case and the meeting is not likely to blemish President Bush's trip to Beijing this weekend."If Sino-Soviet rapprochement contributes to the stability of the region and the globe, then it is all to the good," said one old Asia hand who helped plan Bush's trip.

Soviet President Mikhail Gorbachev's scheduled visit to Beijing in May will end the Sino-Soviet rift and highlight Kremlin concessions on the three points the Chinese have said were preventing improved relations for a decade.

Gorbachev's meeting with senior Chinese leader Deng Xiao-peng will be the first Sino-Soviet summit since Nikita Khrushchev met with Mao Tse-tung in 1959. Mao and Khrushchev later argued over ideology, and Soviet and Chinese troops clashed in the 1960s and 1970s along the 4,670-mile border.

The reason the Chinese are welcoming the Soviet leader, and that the United States does not object, is the marked shift in Kremlin foreign policy in the four years Gorbachev has been in power, according to scholars and government experts.

Before agreeing to meet with the Russians, the Chinese wanted the Soviets out of Afghanistan, the Vietnamese out of Cambodia and a reduction of Soviet troops along the border.

The Kremlin has met or started to meet all of those conditions.

The last Red Army soldier left Afghanistan last week, ending a bloody and futile nine-year occupation.

Vietnam, a close military ally of the Soviet Union, has removed some of the more than 100,000 troops it sent into Cambodia in 1978 and agreed to negotiations over withdrawing the rest.

In 1987, the Soviet Union withdrew 12,000 of its troops from Mongolia, on the Chinese border, and last December Gorbachev announced unspecified further reductions in the estimated 50,000 troops remaining there.

The Sino-Soviet summit, in short, derives from Gorbachev's efforts to change Soviet policies and to make friends rather than enemies around the world.

"There could be a summit only if the Soviet Union changed its pattern of behavior from the last two or three decades," said Stephen Morris, a fellow at the Russian Research Center at Harvard University.

"The things that brought the Soviets and the Chinese together are the same things that brought the Soviets and the Americans together," said Morris, a specialist on Soviet relations with Asian nations.

A State Department specialist on Asia noted that "both the Chinese and the Soviets have stressed that the normalization of their relations will not affect their ties with any other country," in other words, the United States.

If the Soviets fully meet the conditions laid down by the Chinese, said the expert, "that will be a big plus for stability in the region."