BONN — THE ethnic cleansing that marks the war in the former Yugoslavia is eerily familiar to Herbert Hupka. The scenes of roads jammed with refugees fleeing vengeful victors, are reminiscent of what he experienced a half-century ago. Mr. Hupka counts himself among the first victims of modern-day ethnic cleansing - one of about 14 million Germans uprooted from their ancestral homelands in Central and Eastern Europe in the immediate aftermath of World War II. Hupka maintains that if Europe is to enjoy stability and prosperity in the next century, the worst misdeeds of the latter 20th century must be rectified. And one of the gravest injustices, he adds, was that committed against ethnic Germans after the war. ''The expulsion of Germans provided an example for Yugoslavia,'' says Hupka, who was forced to abandon his native region of Silesia, which was transferred from Germany to Poland after the war. He now heads the Association of Silesian Expellees, headquartered in Bonn. Most would concur these days that the German expellees suffered terribly. But whether that injustice warrants compensation remains the subject of often fierce debate among nations. Leaders of those groups expelled from their homes, including Hupka, want formal apologies and compensation, claiming they are innocent victims of war. But in Central Europe - especially the Czech Republic and Poland - they are widely viewed as abettors of wartime Nazi atrocities and receive little sympathy. How the debate is settled could have critical implications for Europe's future. There's no threat of an armed conflict. But the dispute could keep the divisions created by World War II from being resolved. In particular, the expellee question could complicate the efforts of Central European nations to join the European Union, which has emerged as the prime vehicle for promoting continental harmony. Most formerly communist Central European countries see EU membership as a strategic necessity for cementing market and democratic reforms in place. The EU has made reciprocal noises about expanding eastward, but member states balk at the enormous costs the effort would entail. So far, Germany has proved the EU's chief paymaster and foremost advocate of bringing in eastern states. But if the dispute over ethnic Germans upsets domestic politics in Germany, that could help tip the scales against rapid expansion. Ethnic German leaders openly express their desire to link their grievances to EU expansion. ''It would be a mistake to let Poland in [to the EU] without settling this problem,'' Hupka said. Teutonic purge Expellees came from areas in Central and Eastern Europe that had been populated by Germans for centuries; places like East Prussia, now the Russian province of Kaliningrad; Silesia in Poland; and the Sudetenland of the Czech and Slovak republics. After the war, these lands were purged of their Teutonic peoples virtually overnight, as those who suffered under the Nazis sought retribution. Roughly 2 million Germans died during the forced trek to resettle in a rump Germany greatly reduced in size by postwar territorial realignments. During the cold-war years, divided Germany set aside complaints over the expulsion. But discontent bubbled to the surface following 1989's anticommunist revolutions, and was the main reason the German government dithered before recognizing Germany's eastern border with Poland in November 1990. German-Czech relations, meanwhile, still haven't been fully normalized, largely because of the expellee issue. A German-Czech Friendship Treaty was signed in 1992, but did not address many sensitive issues, including the question of compensation for Czech victims of Nazism. All expellee groups share the same general goals. They want a ''right of return,'' allowing them to buy property and enjoy the full rights of a citizen of their heimat, or homeland. Some also want restitution or compensation for their confiscated property. Of all the debates between ethnic Germans and their former homelands, that involving the Sudeten Germans and the Czech Republic is by far the most prickly. The Bavaria-based Sudetendeutsche Landsmannschaft, a group that represents Sudeten Germans, is the most outspoken of expellee organizations. But many Czechs feel Sudeten motives are disingenuous, saying expellees merely want the right to buy up property and assets at special bargain-basement prices. The Sudeten group specifically demands that the Czech government annul the Benes Decrees, the legal foundation for postwar Czechoslovakia's expulsion of Germans. ''The Czechs suffered much less than the French or the Poles under German occupation, but they took the most terrible revenge,'' claims Konrad Badenheuer, a spokesman for the Sudeten group. Kohl's open ears The expelled Germans find support from Chancellor Helmut Kohl's governing coalition, especially from the conservative Christian Social Union (CSU), a party based in the southern state of Bavaria. ''The expellees and refugees have a right to expect us not to ignore the tragedy of their personal fate,'' Chancellor Kohl said in a parliamentary speech this summer. But Kohl also stressed his desire to ''grasp the outstretched hand'' of Germany's neighbors to settle the issues. Prague receives most of Bonn's attention on the affairs of ethnic Germans. Foreign Minister Klaus Kinkel in June said Germany would step up efforts to resolve outstanding differences with the Czech government. Czech leaders have likewise expressed a desire to put the expellee problem behind them. In a February speech, Czech President Vaclav Havel made the most forceful statement of contrition to date, apologizing for Sudetens' mistreatment, and saying ''the time of confrontation must end.'' But kind words haven't greatly improved prospects for a settlement. Bonn remains vague on proposals that could lead to a breakthrough. Prague, meanwhile, maintains that Sudetens were accomplices in Hitler's subjugation of Czechoslovakia. In his speech, Mr. Havel also said Sudeten Germans were largely responsible for their own fate, since they gave ''preference to the dictatorship, confrontation, and violence embodied in Hitler's National Socialism, over democracy, dialogue, and tolerance.'' A decision by the Czech Constitutional Court in March reinforced the government's hard-nosed position. The court upheld the legality of the Benes Decrees. And last week, Czech Prime Minister Vaclav Klaus ruled out making a blanket offer to resettle families of the Sudeten Germans. ''It can be discussed only in individual cases, in accordance with existing Czech law,'' he said. Memories of Munich Sudeten leaders also do little to prepare the ground for compromise. They refuse, for example, to explicitly renounce the premise of the 1938 Munich Pact, the infamous agreement that brought the Sudetenland under Nazi control. Sudetens also insist on direct talks with the Czech government, something that Prague flatly rejects. Some observers worry that a window of opportunity for a German-Czech agreement may be shutting. The biggest hazard is Czech parliamentary elections in 1996. The campaign will further limit the government's ability to cut a deal. ''We'll have to try to straighten this issue out in order not to let it dominate the Czech elections, said Ulrich Irmer, foreign policy spokesman for the Free Democratic Party, Germany's junior coalition member. A paradox for the ethnic Germans is that admitting the Czech Republic and Poland into the EU would satisfy some of their demands. EU regulations, for example, permit citizens to buy property and settle in any member state. Yet the ethnic German groups want to settle their grievances before EU expansion. ''EU membership without abolition of the Benes Decrees is not possible,'' the Sudetens' Badenheuer said of the Czech Republic. This stance puts German Chancellor Helmut Kohl in a tough political position. EU expansion is clearly in Germany's interest. But Mr. Kohl's Christian Democratic Party could need the support of expellees to stay in power after the next election in 1998. These Germans and their descendants make up roughly 15 percent of Germany's electorate, and they tend to vote for Kohl's conservative government. The coalition enjoys only a narrow parliamentary majority. Without heavy support from the expellees, the coalition could face electoral defeat. And Badenheuer, for one, says Sudeten Germans intend to exploit all possibilities to influence policy. ''The current political situation is quite fortuitous for us,'' he said. But if the Kohl government gives in to their demands and delays Czech and Polish admission to the EU, there could be heavy repercussions in Central Europe, Czech political observers warn. ''It could encourage xenophobia, or give ammunition to extreme left- or right-wing political forces,'' said Jiri Pehe, the director of analysis at the Open Media Research Institute in Prague. No 'biological solution' Most of the Germans who lived through the expulsion after World War II are now aged, but time will not diminish the tenacity of either themselves or their children in pressing their claims, Badenheuer said. ''There can be no biological solution to this problem. Sudeten Germans are a little too tough,'' he said. Meanwhile, thousands of Germans from what is now Poland tenaciously cling to their dreams. These people, expelled from Silesia, recognize the current German-Polish border. But many hang on to the hope that one day their homeland once again will become part of Germany. ''With negotiation, maybe things can change,'' Hupka said. ''A big problem is that we are always operating in the shadow of Hitler, and this prevents a fully open discussion. Others can be open, but we must be more delicate.'' r Part 4 of a five-part series on ethnic minorities in Europe. Part 5 runs Aug. 31. Sudeten leaders have not denounced the Munich Pact that brought part of Czechoslovakia under Nazi control in 1938.