BONN -- The Soviet Union, after decades of costly pursuit of superpower status, took a significant step this week toward reintegrating itself politically, economically and culturally with the European continent.

Soviet President Mikhail S. Gorbachev, pledging with West German Chancellor Helmut Kohl that their countries would work together to develop "a peaceful European order," made clear Moscow's preference for a place in the "common European home," as he put it, over the role of a superpower with global interests.

"Although the continent has been divided for decades, the awareness of Europe's identity and common assets has endured and is becoming ever stronger," the two leaders said in a joint declaration. "This development must be encouraged.

"The Soviet Union and the Federal Republic of Germany consider it a paramount objective of their policies to continue Europe's historical traditions and thus contribute towards overcoming the division of Europe. They are resolved to work together in the search to develop a Europe of peace and cooperation--a peaceful European order, a common European home. . . ."

The Soviet Union hopes that such efforts will end its long isolation from the political coalescence and the economic development that have brought Western Europe such stability and prosperity and now threatens to leave Moscow and its allies in Eastern Europe behind completely as the European Community moves to establish a unified market in 1992.

"Gorbachev realized--and it took much insight and integrity to do so--that the Soviet Union had lost in the arms race to the United States, was losing in the economic race to Japan and the European Community and would become a third- or fourth-rank power in 20 or 30 years," a senior European ambassador said in Moscow recently. "The Russian fear is that they will be thought of as Asians, irrelevant to Europe, and just forgotten as we move ahead.

"Gorbachev's best bet, politically and economically, was to return to Europe if the Soviet Union has any chance of keeping up. But that means ending the old thinking of 'We are bigger and stronger than you' or 'We have a better system than you,' and it means more than slogans about peace, friendship and cooperation. If the Russians want a place in Europe, they will have to earn it."

In West Germany, however, Gorbachev found a partner willing--more than Britain and France so far have been--to respond to Soviet needs and accept Moscow's desire to participate in shaping the Europe of the 21st Century.

"The 'division of Europe' has a special meaning here," a senior West German official remarked Wednesday, "and while Kohl understands something different from what Gorbachev means when he says it, there is enough common ground for us to cooperate."

A political commentator put it more tartly on West German television Wednesday: "Mikhail Gorbachev was looking for a solid boulder to be his anchor while he winched the Soviet Union into political and economic modernity, and Helmut Kohl said the Federal Republic of Germany would be that boulder."

In return, the Soviet Union has already begun to soften its opposition--adamant and often angry in the past--to the possible reunification of East and West Germany. Talking with journalists after signing the joint statement, Gorbachev said of that issue, "Let time decide."

"I think that the world is changing, and changing for the better," the Soviet leader said, "and it is opening possibilities for better contacts between all states.

"If we are wise and far-sighted, then a good number of profound changes can take place in Europe and in the whole world."

In October, Gorbachev had bluntly told Kohl in Moscow that even talking about reunification was dangerous, for it threatened Europe's postwar stability.

And one Soviet specialist on Europe, Vladislav Belov, went as far last week as to suggest that he could see growing cooperation between socialist East Germany and capitalist West Germany leading to a decision by them--as "two independent and sovereign states"--on some sort of reunification.

The Berlin Wall, Belov added, would then be little more than a museum piece if it still existed.

"As a symbol, I believe the Wall will be destroyed sometime," he told a briefing at the Foreign Ministry in Moscow.

On this trip, Gorbachev emphasized that, in signing what has already become known as the "Bonn Declaration," "we are drawing a line on the postwar period . . . (and taking) a decisive step in the direction of one another."

For the Soviet Union, the joint statement signed by Gorbachev and Kohl does mark a substantial change in the way it views the world--and itself.