Through the smoke of villages burned by Serbs in Kosovo and cities bombed by the North Atlantic Treaty Organization across Yugoslavia, a conflict over the basic norms of world order can be discerned. The U.S. and its allies claim that the right of ethnic Albanians in Kosovo to a high degree of self-determination justifies foreign interference in Yugoslavia's domestic affairs. Yugoslav President Slobodan Milosevic insists this is an invasion of a sovereign state. Belgrade is backed by Russia and China, both fearful of a precedent being set for outside intervention in rebellious provinces like Chechnya and Tibet. The fight in the Balkans, then, is more than a war between nations; it is a war between the principles of self-determination and sovereignty.

Self-determination is the principle that each nation has the right to govern itself. In practice, this means people should be governed by those who share their nationality defined by language, religion, descent or some other aspect of identity. For members of one ethnic group to rule another is presumed to be illegitimate by today's notions of political justice.

The principle of sovereignty holds that states should be equal in privileges, even if they are unequal in wealth and power. The modern conception of sovereignty originated in Europe in the 17th century. It was extended to the non-European world after World War II, when the European colonial empires in Africa, the Middle East and Asia were broken up. In earlier eras the concept of sovereignty made little sense, for the usual form of political organization was the hierarchical empire. According to the theory of sovereignty, the first privilege of a state is the integrity of its territory.

Self-determination and sovereignty are not always in tension. In nation-states made up of a single or dominant nationality, sovereignty and national self-determination may complement each other. But the two can collide, as in Kosovo, where the conflict between sovereignty and self-determination is present in its most acute form. If the sovereignty of the existing Yugoslav state is to be respected, then its borders must remain intact, even if the international community establishes a protectorate over part or all of Kosovo. If the international community acknowledges the Kosovars' right to self-determination, the result should be partition of Yugoslavia and the independence of Kosovo. The choice between protectorate and partition as the outcome of the war is thus a choice between sovereignty and self-determination.

The puzzle of what to do in a situation like this first confronted U.S. policymakers after World War I. President Woodrow Wilson and leaders of the victorious Allied powers had to decide what political units would replace the Austrian Hapsburg and Ottoman Turkish empires, which had collapsed. Both had ruled sections of the Balkans; both had been multinational.

While championing national self-determination, Wilson did not originate the idea, which dated back to the late 18th century, and had led to the unifications of Germany and Italy in the 1800s. Nor was Wilson responsible for turning World War I into a crusade to break up the Hapsburg and Ottoman empires. In fact, in January 1917, when the U.S. was still neutral, Britain, France and the other Allies demanded "the liberation of the Italians, as also of the Slavs, Romans and Czecho-Slovaks from foreign domination." What is more, Wilson was willing to accept guarantees of autonomy short of sovereignty for ethnic minorities within larger units. In his 14 Points, Wilson declared only that "the peoples of Austria-Hungary should be accorded the freest opportunity of autonomous development." By contrast, Wilson favored "an independent Polish state." Wilson recognized that in the Balkans, the mingling of different ethnic groups made it difficult to draw clean lines for new nation-states.

Despite this, the result of World War I in the Balkans, Central Europe and the Middle East was the partition of empires into successor states, some of which, like Yugoslavia, contained several nationalities. The plight of ethnic Germans outside Germany, and ambitions of groups like the Hungarians and Croats, gave Adolf Hitler an excuse to intervene abroad, increasing not only the influence but the borders of the Third Reich. Following World War II, the minority problem in Central Europe was settled in a most brutal fashion: by the mass transfer of populations.

For 50 years, the communist regimes of the Soviet Union and Tito's Yugoslavia, both multinational countries, managed to suppress ethnic conflicts, but, with the end of the Cold War, both split up along regional and ethnic lines. In response, the U.S. departed from the policy it had supported in Europe since Wilson. President George Bush, and many other Western leaders, initially opposed the breakup of the Soviet Union. Then, a few years later, many U.S. and European leaders opposed the secession of Croatia, Slovenia and other former territories of Serb-dominated Yugoslavia.

If Wilson's policy favored self-determination at the expense of sovereignty, post-Cold War U.S. administrations have argued that ethnic minorities should have autonomy within the framework of larger, multiethnic sovereign states. In frowning on partition and secession, U.S. policymakers were sensitive to the fears of countries like Turkey, Russia and China, which worried that their own ethnic minority regions might seek independence.

Some "realists" urge U.S. policymakers to abandon the idea of national self-determination and treat state borders, however arbitrary, as sacrosanct. In this view, it is no concern of the U.S. if Tibetans, Kurds, Albanian Kosovars, Palestinians and East Timorese are ruled by people of a nationality other than their own. The U.S. government, though, has tried to balance the imperative of preserving existing borders while acknowledging the legitimacy of national self-determination. In Iraq and the Balkans, the U.S. has sought to follow a course like the one promised (but not followed) by Wilson: encouraging "the freest opportunity of autonomous development" for ethnic groups, short of statehood.

The 1995 Dayton accords rejected the partition of Bosnia in favor of a complex formula of autonomy-without-sovereignty. The accords, yet to be implemented, call for a constitutional Rube Goldberg machine: the division of Bosnia into a Bosnian-Croat federation and a Serb section sharing a common federal government, including a rotating presidency in which Bosnian Croats, Serbs and Muslims are all represented. The Rambouillet agreement, which the U.S. tried to impose on Yugoslavia, was based on the same principle of autonomy for Kosovo short of formal independence. Under the peace terms offered by NATO, Kosovo would be granted a high degree of autonomy but not independence, the refugees would be allowed to return and an international peacekeeping force stationed in Kosovo.

As Switzerland, Belgium and Canada prove, complex federal systems can enable two or more nationalities to coexist under a single government. In Lebanon, however, an intricate constitutional compromise between Muslims and Christians broke down into decades of civil war. Foreign military forces under the auspices of NATO or the United Nations would be stationed in Kosovo to prevent such an outcome. Thus Milosevic's Yugoslavia would have to surrender some of its sovereignty, allowing foreign forces on its soil, to preserve the basis of its sovereignty: its territorial integrity.

U.N. protectorates over countries ravaged by internal war are nothing new. But they have been more successful in restoring peace and stability to nation-states experiencing nonethnic civil wars, like Cambodia, than in reuniting territories divided along ethnic lines, like the Palestinian Mandate in the 1940s, Lebanon and Cyprus. In cases of ethnic warfare, peacekeeping missions have become more or less permanent, because communal violence would resume if they left. Indeed, the departure of U.N. personnel in 1994 permitted the genocidal slaughter of as many as a million people in Rwanda.

The alternative to a policy of creating costly international protectorates until permanent peace can be restored would be the formal partition of those entities along ethnic lines. This involves tremendous costs, such as forced population transfers. But the costs of never-ending low-level war may be so great that amputation would be the most humane form of surgery. The partition of a country may violate sovereignty but fulfill self-determination.

Which will it be: preserving existing borders in Yugoslavia at the price of an international protectorate, or carving out one or more new nation-states at the expense of existing borders? In the final analysis, the choice between protectorate and partition, between Yugoslav sovereignty and Kosovar self-determination, may be settled in the U.S. or in other major NATO powers, not on the battlefield.

Of the two options, partition is cheaper, from the perspective of Washington and its allies. It would be easier to equip the army of an independent Kosovo to defend itself than to station foreign troops there for years or even decades. What is more, as the Korean War and Gulf War showed, it is easier to rally international support to prevent a cross-border invasion of one sovereign state by another than to intervene in relations between a capital and a province.

The choice in the Balkans, then, is not between principle and amorality, but between two competing principles: self-determination and sovereignty. Putting sovereignty above self-determination leads to a protectorate over Kosovo; putting self-determination over sovereignty leads to a Kosovo independent of Serb-controlled Yugoslavia. Those who must live with the choice are in the Balkans; but it is a choice the NATO allies ultimately have the power to make.