BONN, MAY 24 -- A reuniting Germany needs the Soviet Union's blessing before it can declare itself whole. A struggling Soviet Union needs the technical know-how and economic support of the rich German state now in formation.

As a new German power rises in the center of Europe and the Soviet empire collapses in the east, the two countries are engaged in a high-stakes tug of war over the political and military reshaping of Europe.

Despite the confusing signals out of Moscow, Bonn's leaders are supremely confident that the Soviets eventually will approve unification of the two Germanys and its central sticking point, German membership in NATO. The backbone of the German confidence is an equally supreme willingness to pay for the Soviet "yes."

"What we are seeing now are the birth pains of a new relationship between Germany and the Soviet Union," a top West German official said. "They know we are not willing to bring about unification without Soviet consent. And we are prepared to accept obligations in exchange for that consent."

Put more plainly, "the Russians are fishing for a price the West will pay for NATO membership," said Josef Joffe, foreign editor of the Sueddeutsche Zeitung, a Munich daily. The price the Soviets extract may go a long way toward determining the economic and political fate of Mikhail Gorbachev's reform efforts.

The struggle now underway between Bonn and Moscow -- a crucial topic in next week's Bush-Gorbachev summit -- is nothing new. For centuries, Germany and Russia have bounced from alliance to war and back again.

The last prince of Prussia, Louis Ferdinand, now 81, married a Russian, as did his grandfather, Kaiser Wilhelm II. Adolf Hitler's view of Russia was less benign; the Nazi dictator considered the massive nation useful only as Lebensraum -- extra living space -- for his penned-in people.

These days, West German Chancellor Helmut Kohl speaks optimistically of a "relationship of the soul between Russians and Germans," even as the Soviets pepper the West with a bewildering barrage of conditions for approval of reunification.

"It's a pattern of attraction and repulsion, never quite consummated by either side," Joffe said.

East and West Germany have joined the Western allies in support of German membership in the North Atlantic Treaty Organization. The Soviets have tried all manner of tactics to press the West into giving up on NATO membership or, more likely, dramatically changing the nature of the alliance. They have threatened to keep their 380,000 troops in East Germany indefinitely. They have demanded limits on Germany's military might. They have asked for nuclear weapons to be removed from German soil.

The eventual price of the Soviet blessing will take the form of a number -- the amount of money Bonn will pay Moscow in outright economic aid and as support to keep Soviet troops in East Germany temporarily.

West German negotiators are talking about buying supplies for Soviet troops and eventually building housing for them back in the Soviet Union. The cost is expected to be considerably more than the $180 million a year that East Germany now pays to subsidize the Soviet military presence.

But the price of German unity will probably also be paid in political and military concessions -- some response to the various Soviet demands.

West Germans insist they can find an acceptable price without jeopardizing the Western alliance. Bonn is willing to cut its own military by nearly half and to promise to post no Western troops in what is now East Germany. And the West Germans this week began talking publicly about a wholesale change in Western nuclear strategy -- proposing to use nuclear force only against nuclear attack, rather than as insurance against a conventional war from the east.

In exchange, the West Germans want Soviet troops out of Germany within five years. The Soviets have not yet responded.

Figuring out the price of Soviet consent is high on the agenda at the Bush-Gorbachev summit, at the six-nation talks on German unification, and in two sets of direct negotiations between Moscow and Bonn.

Those last talks show how deeply the West Germans want Soviet assent. Official talks between the two countries have been conducted by Foreign Ministry diplomats since May 7. Then, last week, Kohl's top foreign policy aide, Horst Teltschik, secretly flew to Moscow for separate talks.

That move miffed Foreign Minister Hans-Dietrich Genscher. "These secret talks play into the Soviets' hands, letting them think they can play the chancellor off {against} the foreign minister," a Foreign Ministry source said. "This can only make it more expensive for us."

"In the short run, Germany is only interested in settling the unification question," said Meinhard Miegel, director of the Institute for Economic and Social Politics in Bonn. "Germany will do everything to speed up the process and remove the obstacles.

"The next question is how German-Soviet relations will develop over five or 10 years. This could become an intense partnership, almost a special relationship," such as West Germany now enjoys with the United States.

The danger of such a path is clear to the Kohl government, which doesn't want to do anything the Western allies could interpret as a retreat from Bonn's postwar commitment to the West.

"The Germans are back where they never wanted to be," Joffe said. "If they move an inch to the East, they lose a mile in the West."

Despite the danger, Bonn officials argue that the political geography of Europe makes stronger German-Soviet ties inevitable. The Soviets' largest Eastern Bloc trade partner is East Germany. The Soviets' largest Western trade partner is West Germany.

After four decades of Communist control, many East Germans speak Russian. Tens of thousands of them know the Soviet economy and bureaucracy better than Western executives do. The combination of East German knowledge and West German money makes a united Germany the natural partner for a Soviet Union hungry for outside investment.

The Germans wield the economic power while the Soviets hold onto a good measure of political leverage. "The Soviets have the theoretical ability to block the whole process of unification," a Bonn diplomat said. "To unify Germany against the will of the Soviet Union would automatically destabilize the political-military situation in Europe."

Of course, the Soviets do not hold all the cards. They will wake up July 2 to an economically reunited Germany in which their rubles will no longer buy the East German supplies they need. Their new dependence on West German hard currency will put the Soviets under increasing pressure to accept political unification.

"The economic side will work out," said a Bonn official. "The real problem is not economics or security. . . . The real problem is saving face, convincing the marshals and the Soviet people that Gorbachev did not create a new threat by losing Eastern Europe. That's what the talks are really about. It's classic diplomacy, putting the best light on a defeat."