BONN — The German chancellor called it a special responsibility of his generation.
The Soviet president described it simply as realpolitik.
Whatever the description, those who crowded into the stuffy little auditorium in the northern Caucasus spa town of Zheleznovodsk on July 16 and heard Chancellor Helmut Kohl and President Mikhail S. Gorbachev report on results of their two-day meeting knew they had witnessed history.
The Soviet Union and Germany--Europe's biggest power and its richest--had with chilling suddenness buried half a century of bitter differences that had dragged them through Europe's bloodiest war and estranged them during a prolonged, uneasy peace.
From a thinly disguised fear of German revanchism, Moscow had embraced the inevitability of German reunification as a cornerstone of "the new political order" that Gorbachev is counting on so heavily.
In the process, the door has opened to a new and hugely important relationship--as rich in potential as it is loaded with uncertainty.
"We stem from different parts of global civilization, but we feel that we belong together," Gorbachev explained to those listening in Zheleznovodsk.
Anyone witnessing the champagne and euphoria that filled the chancellor's aircraft as it winged its way home from the Caucasus last July would be left with little doubt that Kohl believed the same.
How these two nations manage this new beginning will do much to influence the future shape of a continent in the midst of greater change that at any time in nearly two centuries.
If it succeeds, analysts believe that the new relationship could become the key element in overcoming the economic and political differences of Europe's long East-West division. Failure would likely deepen them further.
"Germany is a huge force in the center of Europe," Soviet Foreign Minister Eduard A. Shevardnadze told the Supreme Soviet last month. "The future of Europe largely depends on how we relate to this giant."
History and the weight of numbers alone make Shevardnadze's assessment hard to reject.
Including the Soviet Union's Asian mass, the two nations account for half of Europe's population and nearly half of its total production. Together, they have a land area twice that of Europe alone.
Later this month, Gorbachev is expected to make his first trip to the newly united Germany and sign a 20-year Soviet-German treaty of "good-neighborliness, partnership and cooperation" that will act as a framework for the new ties.
Rich and warm in its language, the treaty symbolizes the historical watershed.
"With this treaty there will be a partnership, and that is fundamentally new," said Valentin M. Falin, secretary of the Soviet Communist Party Central Committee and Gorbachev's principal adviser on German policy. "And we will be serious partners, economically and politically."
Added another foreign policy specialist at the Central Committee: "We decided on friendship. Now we are waiting, rather expectantly, to see what that friendship brings."
So are many others.
The direction and intensity of this new German-Soviet relationship remains one of the biggest question marks in a fast-changing European order--its future as uncertain as that of the Soviet Union itself.
Certainly, great potential is there.
As the Soviet empire lurches from crisis to crisis, it is the economically strong, politically resurgent Germany that seems to have the most of what Moscow so desperately needs if it is to survive as a stable nation.
With a trade volume of $34 billion last year, Germany is already the Soviets' largest trading partner.
In a new political climate, German deutsche marks, not Soviet missiles, have become more immediately relevant to the preservation of Moscow's empire.
So far this year, Germany has pledged more than 20 billion marks (about $13 billion) to the Soviets in one form or another.
German loans last summer--among them a $3-billion bank credit that constituted the single largest transaction of its kind ever extended to the Soviet Union--were essential in ensuring the smooth flow of imports necessary to keep key sectors of the Soviet economy from total collapse.
Given domestic political uncertainties in the Soviet Union, little time has been spent trying to assess the long-range potential of Soviet-German trade. However, Heinrich Machowski, an analyst at the German Economic Institute in Berlin, speculates that overall Soviet trade potential could eventually triple, with Germany getting more than its share of the increase.
Bonn and Moscow now also share more common political goals than any other two nations across Europe's old East-West divide.
A stable Soviet Union, well integrated into Europe, is accepted along the Rhine as essential for Germany's own prosperity.