Mostar's Croat mayor, Ivan Prskalo, wants to exhume the remains of people buried in the cemetery, ostensibly because their shallow graves pose health risks. The real motives behind his proposal are, to Muslims and Western diplomats monitoring the situation, transparently clear. They are to separate the remains of Croats from those of Muslims, to create an "ethnically cleansed", purely Croat cemetery, and to erase from history and people's memories the fact that Croats and Muslims were once united in a common cause.
This unpleasant episode serves as a reminder, if Europeans need one, that extreme nationalism, political persecution and the aggressive celebration of one people's supposed superiority over another have been features all too typical of our continent in this century. From Ireland to Russia, from Germany to Turkey, national, ethnic and religious minorities have been the victims of hatred and violence on a scale without historical precedent.
Although almost 50 years passed without a major conflagration after 1945, the Bosnian war confirmed that Europe had not seen the last of conflicts set alight by extremists in positions of power and fanned by popular cultures of nationally or ethnically based intolerance, rivalry, suspicion and ignorance.
But was the Bosnian war exceptional? Are Mr Prskalo and others like him members of a dying breed? Will Europe prove capable of overcoming poisonous nationalisms in the next century, or will nationalist poisons overcome Europe?
With the emotions of Serbs, Croats and Muslims still raw, and with the long-simmering Cyprus dispute threatening to boil over once more, some Europeans find more grounds for pessimism than hope. Yet the picture is by no means uniformly bleak. In much of central and eastern Europe, the region most troubled by nationalist and ethnic confrontations in recent years, the waters are calmer than at any time since the demise of Communism in 1989.
Hungary and Romania, two neighbours with historical grudges against each other, have signed a treaty pledging respect for existing frontiers and minority rights. So have Hungary and Slovakia. Romania and Ukraine are set to follow suit. Further to the north, Poland has settled its borders and proclaimed new friendships with Germany and Lithuania.
These treaties could be dismissed as mere pieces of paper, which any of the governments in question will disregard if it feels so inclined. However, when compared with the various broken promises of lasting peace and goodwill that the states of western, central and eastern Europe made to one another in the 1920s and 1930s, the new treaties seem to carry greater sincerity and weight.
For one thing, the Hungarians, Romanians, Ukrainians and others recognise that the treaties have an intrinsic value bearing on the region's stability and prosperity. For another, there is, this time, no great outside power - an expansionist, racist Nazi Germany or an autarkic, totalitarian Soviet Union - wishing to subjugate the region.
Lastly, if the new democracies that have signed the treaties of reconciliation wish to be included in the most important Western institutions, notably Nato and the European Union, they will have a strong incentive to honour their commitments.
Membership of such organisations offers the central and eastern Europeans the chance to heal old wounds in the way that France and Germany did after 1945. By the same token, failure to meet appropriate standards of internal democracy and respect for civil rights will bring international isolation.
This is a lesson that Serbia and Croatia are still learning. Eighteen months after the end of the Bosnian war, neither is considered ready for complete international rehabilitation. The US Secretary of State, Madeleine Albright, put the point bluntly in Washington on 15 May when she warned the visiting Croatian foreign minister that recent Croatian mob violence against minority Serbs had been intolerable and would hold up Croatia's integration into the Western world.
The lesson applies to Slovakia, too, though in less stark fashion. Thanks to the bullying intolerance and occasionally sinister political methods of its prime minister, Vladimir Meciar, Slovakia is being left behind as its Czech, Hungarian and Polish neighbours proceed to Nato membership.
Thoughtful Slovaks realise this and are impatient for the chance to vote out Mr Meciar at the next election. They see how the international image of Bulgaria and Romania underwent a vast improvement after the recent election victories of reformist opposition movements. In Romania, the triumph of enlightened democrats over ex-Communists and rabid nationalists could prove to be a watershed in the nation's history, a decisive break with this century's Romanian tradition of reaction, repression and extreme nationalism.
The promising example set by the new leaders of Bulgaria and Romania, Ivan Kostov and Emil Constantinescu, has been matched to a considerable extent by Greece's Prime Minister, Costas Simitis. For several years after 1992, Greece's foreign relations were in turmoil. Quarrels with Albania, the former Yugoslav republic of Macedonia and Turkey left Greece isolated in the EU and with not many friends outside, one embarrassing exception being Serbia. A mood of nationalist hysteria was being encouraged inside Greece over the alleged threat to the country posed by ex-Yugoslav Macedonia.
Mr Simitis has tried with some success to change all this, since he replaced the dying Andreas Papandreou as prime minister in early 1996. He has played down the Macedonian issue, cultivated better relations with Albania and, most strikingly, taken several small but significant steps in the direction of a dialogue with Turkey. Of these, the one winning most attention is the decision to set up a committee of Greek and Turkish experts to look at what are called "procedural aspects" of solving the problems in Greek- Turkish relations.
It may not sound like much, but the importance of this initiative becomes clear when it is remembered that it is less than 18 months since Greece and Turkey came close to war over a crop of disputed islets in the Aegean Sea. More than a few European diplomats and foreign policy specialists have warned recently that, if a war were to break out in Europe early in the next century, the likeliest cause would be Greek-Turkish hostility. Tensions on Cyprus rose last year to levels unseen since the 1974 Turkish invasion, and grew especially sharp last January when the Greek Cypriot government announced that it was buying a batch of Russian surface-to- air missiles.
It would be futile to pretend that these tensions are going to disappear quickly, or that the type of virulent nationalism that led to Greek-Turkish wars in the first quarter of this century is on the point of dying out. Yet it may just be that, having looked at the abyss, the Greek and Turkish governments have decided to pull back. There is certainly a more positive spirit of co-operation in the Aegean air now than for many a year. It will need active involvement from the United States and the EU to keep it alive.
Further east, in Russia and Ukraine, the political skies are much less cloudy and threatening than many commentators in the West assume. Ultra- nationalism and ethnically related violence, two vicious products of the collapse of Communism in 1991, are on the wane. Three particular developments in the last year suggest that Russia and Ukraine, whose stability is so crucial to Europe's security, may have passed the point of greatest danger.
The first is the end of the Chechen conflict, a war which showed Russia's young democracy in its worst light. It seems unlikely that President Boris Yeltsin and his newly appointed reformist government has any intention of relaunching the war. That, in turn, reduces the risk of multiple Russian- Islamic guerrilla conflicts extending across much of the northern Caucacus for well into the next century. Such a risk appeared quite high when the Russian army intervened in Chechnya in December 1994.
The second development is the lapse into relative obscurity of Vladimir Zhirinovsky and his noxious brand of extreme Russian nationalism. Even the more sanitised version purveyed by the neo-Communist Gennady Zyuganov, Mr Yeltsin's presidential challenger last year, has less and less popular appeal in Russia.
The third is the successful consolidation of the Ukrainian state and the absence of any substantial separatist movement in the Russian-populated regions of eastern Ukraine. Russian separatism in the Crimean peninsula loomed as a serious threat in 1993-94, but now seems a spent force. Though not yet settled on firm foundations, Russian-Ukrainian relations no longer provide grounds for fearing the apocalypse of a war that might suck in the rest of Europe.
The gradual stabilisation of central and eastern Europe is symbolised by Nato's deal this week with Russia, under which the two sides will forge a close political and security partnership while enabling the Western alliance to incorporate the Czech Republic, Hungary and Poland. It is a deal that needs to be followed up with special arrangements for others in the region, notably Ukraine and the Baltic states. The EU's enlargement eastwards will also help.
There are, then, some grounds for hoping that Europe will be a more secure, more tolerant continent in the next century. But will it lead, in time, to the emergence of a common European identity, complementing national identities?
Massimo d'Azeglio, the Italian statesman, said after the 1859-60 Wars of Unification: "We have created Italy. Now we have to create the Italians."
In this century, after two world wars and the Cold War, Europe is finally being created as a free, undivided entity. To create Europeans is the task of the next.