During the cold war's long struggle, when one superpower's gain in territory or influence was a loss for the other, the maverick communist state of Yugoslavia was a strategic target for both the U.S. and the Soviet Union. But the region's ethnic hatreds have been around much longer than that, epitomized by the rancorous quarrels that touched off World War I.
Ironically, the end of the East-West conflict has rekindled those old animosities, tamped down for decades under communist rule. The re-emergence of Balkan rivalries unnerves many in Europe, but Yugoslavia's turmoil today is important -- and dangerous -- mostly to...