THE MALTA SUMMIT : Gorbachev Reforms Stir Global Changes : Foreign Policy: <i> Perestroika</i> , intended to change the Soviet Union, is paying dividends abroad as the specter of the Cold War recedes.

When Mikhail S. Gorbachev assumed the leadership of the Soviet Union almost five years ago, he set out to transform the country and stem the collapse of its political and economic system. In the process, he has begun reshaping world politics as well.

The reforms that Gorbachev undertook have dramatically altered the Soviet Union’s relations with the West, turning what President Ronald Reagan called the “evil empire” into what President Bush now hails as a “partner for peace.”

Warming to the charismatic Soviet leader and his efforts to replace the totalitarian system that had existed since the time of the dictator Josef Stalin with political pluralism and a market economy, the West saw Gorbachev, as British Prime Minister Margaret Thatcher put it first, as “a man we can do business with.”

The changes Gorbachev is attempting at home--the Communist Party’s progressive sharing of power, the freeing of the Soviet economy from rigid central planning, the opening to the outside world, the growing respect for human rights--have fascinated the West and increasingly diminished its long-held perception of the “Soviet threat.”

With their growing resonance in other socialist countries, even in such formerly hard-line states as East Germany and Bulgaria, Gorbachev’s reforms now promise to bring historic change to Europe and to East-West relations as a whole.

Perestroika , begun as an effort to pull the Soviet Union out of two decades of political, economic and social stagnation, has brought Moscow more prestige and influence than its military might did. And what was an urgent necessity in terms of domestic policy has become an unexpected virtue in foreign affairs.

Appraising their country’s position in the world, Soviet leaders and foreign affairs specialists are able to argue that their reforms are creating a political watershed on the eve of the 21st Century, not only for their country and other socialist countries but virtually around the world.

“We see that many countries and people in the world are responding actively and positively to perestroika ,” Alexander N. Yakovlev, a member of the Communist Party’s ruling Politburo and one of Gorbachev’s closest advisers, said recently on a visit to Tokyo. “It is tackling not only the problems of Soviet society; it is also looking for answers to the questions faced by the whole international community.”

As a result of these shifts, Gorbachev goes to his first summit meeting with President Bush off Malta this weekend with confidence that a new relationship is developing not only between the Soviet Union and the United States but between East and West, a relationship that Soviet officials see ending the Cold War and forming the basis of a new international order.

“We are in one of the greatest moments of the 20th Century,” Leonid N. Dobrokhotov, a senior official in the Communist Party’s policy-making Central Committee, said in an interview. “A fundamental revolution in people’s mentality has occurred. . . . Our relations with the United States will not--cannot--return to what they were for so many years. . . . And on that basis, we can honestly look forward to further changes in international relations.”

Tired of the Cold War years of nuclear threat and stalemate, the West has welcomed the changes in the Soviet Union’s foreign policy under Gorbachev--his substitution of a “balance of interests” for the old balance of power, the abandonment of confrontation in search of cooperation and the end of “class struggle”--as the basis for Soviet actions around the world.

“We can take pride in the fact that our new revolution acts as a locomotive of positive change in the world and has a favorable effect on world politics, warming the international climate,” Eduard A. Shevardnadze, the Soviet foreign minister, told a legislative committee reviewing the country’s foreign policy this month.

“Today, we see the signs of the consolidation of all mankind in response to the threats--nuclear, economic and ecological--to our civilization. This is the only way to our survival. The sooner this is understood, the greater our chances for salvation.”

Brought together as “new political thinking,” the far-reaching changes in Soviet foreign policy have given Moscow considerable leverage on most international issues. Under Gorbachev, the Soviet Union generally takes the initiative, leaving the West to match it in pragmatism and willingness to rethink old positions.

Georgy A. Arbatov, the veteran director of the Institute for the Study of the United States and Canada and an influential member of the party Central Committee, calls this the “Gorbachev challenge.”

“We take what we call our ‘new political thinking’ right to the people,” Arbatov said. “We want them to see what we are proposing and to compare it to what has existed for so long, to what others are proposing. . . . And people have begun to see that we are not doomed to live under that modern sword of Damocles--the threat of nuclear war.”

The term “new political thinking” is summed up by Yuri A. Krasin, rector of the party’s Institute of Social Sciences, as starting from “an overall change in outlook on security, moving from the balance of forces to a balance of interests, from force and the threat of force to confidence and trust, from the projection of military power to sufficient defense.”

“What we have realized and are trying to get others to share,” he told a military conference here not long ago, “is that no real security is obtainable in this age without a general agreement that is based on trust . . . but for trust to work, we need sweeping changes in international relations.”

Recalling the theory of an escalating thermonuclear conflict developed during the Cold War by the late American strategist Herman Kahn, Krasin proposed “a reverse model” of de-escalation, characterized by unilateral moves to signal good will and then by reciprocal and mutual measures.

Andrei A. Kokoshin, a political scientist at the U.S.A. Institute here, said that in the searching reappraisal that came with Gorbachev’s assumption of the leadership, the Soviet Union realized that the West’s military strength, although growing, was not the greatest threat to Soviet national survival.

A greater threat, particularly to the Soviet Union’s posture as a great power, stemmed, he said, from the gap between its scientific-technical level and that of the West, and from its failure to improve living standards through economic development.

‘Cost Us a Lot’

“Military parity (with the United States) was a key guarantee of national security, but it cost us a lot in sacrifice and expenditures,” Kokoshin said. “It also left us vulnerable in other ways, some of them unforeseen, and today we attach priority to political means in ensuring our national security.”

Although the greatest impact of Moscow’s foreign policy reorientation has been on Soviet-American relations and, more broadly, on the whole East-West relationship, Soviet officials quickly tick off other changes of considerable consequence in the past two years. Some examples:

“In setting Eastern Europe ‘free,’ we also freed ourselves,” a foreign policy adviser to Gorbachev said, asking not to be quoted by name. “The prestige of socialism is enhanced; no one talks any longer about ‘satellites’ or the ‘Iron Curtain.’ We are not burdened with their mistakes, nor they with ours. Recognizing the right of every nation to choose its political and economic system freely was not only the moral thing to do, it was the politically smart thing. . . . In the long run, we will be drawn together by natural interests, and that will be a far healthier and stronger basis for relations. As the confrontation with the West is reduced, our security is increased. Already we are planning the transformation of the Warsaw Pact into a political grouping to help us manage the transition away from confrontation.”

Western Europe, where Gorbachev regularly ranks in opinion polls as the world’s most popular political figure, is rapidly adjusting its vision of the future to include a democratized Soviet Union and Eastern Europe. Gorbachev, who visited Britain, Finland, France and West Germany before his current trip to Italy and the Vatican, has won considerable support for what he calls “the common European home,” a new Europe no longer divided into armed camps but united through shared values and such goals as disarmament, economic cooperation and environmental protection.

The long estrangement between China and the Soviet Union was ended with Gorbachev’s trip to Beijing in May. The rapprochement reflected not only Moscow’s acknowledgment that every socialist country had to find its own way but its willingness to resolve outstanding disputes with Beijing. The benefit to Moscow was great--the further reduction of tension along the 4,600-mile Sino-Soviet border, allowing for a substantial reduction in the forces it had stationed there for more than 20 years, and the prospect of economic cooperation that would bring development to Siberia and the Soviet Far East.

In the Third World, the Soviet Union is limiting its exposure to what it can afford, politically as well as economically. No longer does it preach Soviet-style socialism as the best course for development, and no longer does it offer to underwrite such efforts with military and economic assistance on the vast scale of the 1960s and 1970s.

Soviet troops completed their withdrawal from Afghanistan in February, and after nine months, the Moscow-backed government of President Najibullah remains in place. Moscow assisted directly in the U.S. mediation effort that led to the recent elections in Namibia and the accompanying withdrawal of Cuban forces from Angola. And the Soviet Union continues to promote a political settlement of the conflict in Cambodia following the Vietnamese pullout there.

“We have created some space for ourselves in which to maneuver,” Andrei V. Nikiforov, the editor of the influential journal USA, said in an interview. “Gorbachev goes to Malta without nearly the problems he had pressing on him 18 months ago when he met Reagan here, or even last year when he met Reagan and Bush in New York. Foreign policy no longer constricts us in the way it did for so many years. We have a new posture in the world today.”