THE disintegration of the Soviet empire will surely rank as a turning point of our time. It is one of those rare events that make clear the distinction between what is history and what is merely news.The suddenness of the collapse and the scope of political and economic changes underway throughout the former Soviet Union and Eastern Europe are almost unprecedented, according to historians. The problem now will be making the changes work while avoiding the recriminations and violence which have marked past periods of revolutionary political transition. "There have been very few peaceful breakups of empires," says John Lewis Gaddis, director of Ohio University's Contemporary History Institute. In historical terms, it is already remarkable that so much change has occurred with so little fighting. In September 1989, who would have believed that within two years the world would see the Berlin Wall torn down, Germany reunited, former Warsaw Pact nations clamoring to join NATO, and the Soviet Union itself disbanded - all without any concerted resistance? The situation in Yugoslavia stands as a warning of what the Soviet breakup has avoided, or may yet become. Previous European political upheavals of this century invariably followed the bloodshed of wars. The Russian Revolution of 1917 came near the end of World War I; construction of the Iron Curtain across Eastern Europe was a political consequence of the position of Allied armies at the end of World War II. "It is close to unprecedented to have this shift taking place without war," says Dr. Gaddis. One analogous period in recent history might well be the 1890s to the beginning of World War I. During that time the post-Waterloo structure of European power that had survived throughout the 19th century began to break up for good, notes Walter LaFeber, a professor of history at Cornell University. Feelings of nationalism and ethnicism exploded throughout the Balkans and other areas of Eastern and Central Europe. The world order turned upside down, with old power Britain declining in importance and upst arts Germany, Japan, and the United States rising. The fragmentation of power and empires was similar to what is sweeping Europe today. In that sense the fall of communism "is an interesting movement back into history," says Dr. LaFeber. The French Revolution of 1789 also provides striking similarities with today's events in the Soviet Union. Both involved ossified regimes stretched too far abroad, while not providing adequate consumer comfort at home, says Simon Schama, a professor of history at Harvard and author of "Citizens," a history of the French Revolution. Both revolutions involved rulers (Gorbachev, Louis XVI) who waffled about introducing reforms. At their height both involved huge crowds physically storming symbols of their overseers: the Bastille in France and the square in front of KGB headquarters in Moscow. This comparison gives one pause, considering the terror that later enveloped France, but Dr. Schama cautions that historical analogies shouldn't be taken too literally. He says there are two key problems illustrated by the French Revolution that Soviet citizens now face: "How to make economic changes and political reform work in tandem . . . and how to make a big state effective while securing freedom and justice." Americans forget, he points out, that their nation's relatively smooth transition from the violence of revolution to the debate of constructing new political institutions is, in historical terms, unique. The US was helped in that transition by an already deeply rooted sense of self-government created by the Virginia House of Burgesses and other colonial political institutions. The Soviet Union, however, has no such history and is still learning true democracy from scratch. In the Russian past there have been popular rebellions, and there has been some experience with urban self-government, says William McNeill, professor of history emeritus at the University of Chicago. But until this century the vast majority of the population consisted of peasants who worked the land. "What is different about the Russian past is that they never had the practice of majority vote," he says. "They had the feeling that unless everybody agreed, it wasn't right." Dr. McNeill says that he thinks such a frame of mind may well persist in the Soviet Union, making possible the return of dictatorship in some form. The great remaining question, he says, is whether the economic troubles almost certainly looming on the horizon will lead to further upheaval. Future stability in the region is a major Western concern. Another historical analogy may shed light on this problem: the breakup of the Austro-Hungarian Empire at the end of World War I. The Austro-Hungarian dissoluti on resulted in whole new states, such as Czechoslovakia and Yugoslavia, and radically changed the borders of older nations such as Poland and Romania. In geopolitical terms, the major problem was that these changes left "small, ineffective, and rather tempting states," says Charles Gati, an Eastern European expert at Union College. It should have been clear in 1920 that a larger power would inevitably move into this vacuum, he says. Hitler's Germany finally did, sparking World War II. With Yugoslavia now potentially dividing into microstates, plus the independence of the Baltics and the looser Soviet republic, such a situation might reoccur.