THE East-West fault line running through Central Europe has slipped, shifting the political fissures that have marked the postwar division of the continent. Even though surface movements appear sharp, and evidence of a new order is emerging, the old system is not entirely dead. Military and political balances are even more crucial and are under closer scrutiny by foreign and defense ministries.
Two questions are central: Can the superpowers and European nations manage the changes and avoid conflict? Or is the situation in Eastern Europe out of control and therefore dangerous?
What happens next in Eastern and Central Europe hinges largely on the man who has set change in motion: Mr. Gorbachev. The unknown is exactly what the Soviets foresee as the future map of Europe. This issue will likely top President Bush's agenda as he and Gorbachev meet in the Mediterranean Sea in early December for their first summit.
Recent months have seen the remains of Stalinism being eroded in country after country of Eastern Europe - first Poland, then Hungary, and now East Germany and Bulgaria.
As the West basks in the euphoria these moves have engendered, Western publics and governments face some stubborn facts. There are still 380,000 Soviet troops stationed in East Germany. Hundreds of thousands more are positioned in Poland, Czechoslovakia, and Hungary. The Warsaw Pact retains a 3-to-1 advantage in tanks and artillery, a 2-to-1 advantage in aircraft, and thousands of nuclear weapons.
Soviet troops in East Germany are increasingly isolated. Within a year, they could be sitting in a country with a noncommunist government. Their supply lines run through Poland, which already has a noncommunist government. The same situation could prevail in Hungary as well.
Surrounded by three countries that are noncommunist or headed swiftly in that direction, Czechoslovakia's hard-liners will find their position eroding. Czechs and Slovaks, the country's two dominant ethnic groups, may be emboldened to agitate for the government's dismissal, as citizens in neighboring countries have done. When Czechoslovakia ultimately moves down the reform path, Soviet troops in the entire region will be even more exposed.
Doubtless Gorbachev and other Soviet leaders are aware of this. That they have made no moves to prevent the noncommunist drift in their satellite states apparently means they are planning either to leave their troops in place under changed circumstances or to withdraw them - quite possibly as part of a negotiated settlement with NATO in the Conventional Force Reduction talks. That they would withdraw them without obtaining something in exchange from the West - and especially from the US - seems doubtful at present.
There is also the question of what happens to East Germany. The desire of the German people for reunification is quite clear. What is not clear is when, and under what circumstances, such a reunification might take place. There are several possible scenarios:
The Soviets may decide they cannot tolerate reunification and must forcibly prevent it. This seems a likely stance if reunification were attempted. A Soviet spokesman last weekend said German reunification was ``out of the question.''
The Soviets could maintain a public position against reunification, but gradually negotiate their way out of Germany and allow it to occur. This would probably take several years, perhaps even decades. It would depend on progress in both nuclear and conventional arms-control talks.
The Soviets would also probably require that West Germany pull out of NATO as the price of reunification, and that the reconstituted Germany be a neutral state, following the Austrian example. It is hard to believe the Soviets would accept a new German state to remain a part of NATO, effectively giving the Atlantic alliance a border with Poland.
The German people could take matters into their own hands and reunify in the face of Soviet protests. This scenario would be the most fraught with danger, unless the Soviets have lost the political will to control events in East Germany, which seems unlikely. If the Soviets believe their vital interests and security are threatened by such a move, they will not hesitate to use force to prevent it.
Finally, there is the question of the future of both the Warsaw Pact and NATO alliances. The Soviets have given little indication at this point that they will tolerate the withdrawal of any Warsaw Pact state from that alliance. And NATO would have to decide what it would become in the face of a greatly diminished threat from the Warsaw Pact nations and with a more powerful, and perhaps neutral, Germany.
Eliminating the effects of Stalin's legacy in the Soviet Union itself has proven a slow process - begun by Nikita Khrushchev and revived by Mikhail Gorbachev - that still has a long way to go.
The division of Germany and Europe into democratic and Soviet communist states was the result of decisions taken at the wartime Yalta conference by US President Roosevelt, British Prime Minister Churchill, and Soviet dictator Stalin.
They divided Europe into spheres of influence. But they did not provide for what later amounted to a Soviet takeover of all of Eastern and Central Europe and the installation of communist regimes there. That was Stalin's doing.
Governments around the world are rushing to come to grips with the implications of the new reality emerging in Europe.