ALTHOUGH U.S. and allied warplanes in one sense won the war in Kosovo last spring, President Clinton's visit yesterday was far from a victory tour. As he acknowledged, Kosovo faces grave problems. The ultimate judgment on U.S. military intervention will depend on how successfully the United States, the United Nations and Kosovars themselves face those problems.

Mr. Clinton emphasized to the ethnic Albanian majority of Kosovo the importance of tolerance toward their Serb neighbors. He was right to do so but also to admit what a tall challenge tolerance is. The ethnic Albanians, who before the war were nine-tenths of the province's population, lived for a decade under repressive Serb rule. They then spent a year as targets of an increasingly vicious and systematic Serb military campaign that burned homes and villages, killed young and old men and drove most of the population out of the country. Allied bombing forced Serb strongman Slobodan Milosevic to withdraw his troops and allow ethnic Albanians to return home. But it could not undo the damage, retrieve the dead or erase the memories.

That's no justification now for revenge killing of Serb civilians. NATO and U.N. administrators of Kosovo shouldn't tolerate such abuses by the Kosovo Liberation Army nor by anyone else. In the long run, though, a vision of a multiethnic Kosovo isn't likely to take hold unless life improves for members of all ethnicities. That means the U.N. administrators have to do better at basic tasks of rebuilding and restoring water and electricity. Other organizations, such as the Organization for Security and Cooperation in Europe, have to stop squabbling and competing for power. And European and North American nations have to be more generous so that the United Nations can pay the teachers, police and others it is hiring. To do otherwise would hand Mr. Milosevic a belated victory.

It also will be important to let Kosovars take more control of their lives. Some international officials are reluctant to allow elections for fear that the wrong faction--the intolerant Albanians--will win. But the longer the United Nations and NATO run Kosovo without local involvement, the greater the danger that they will be seen as unfriendly occupiers. At least on a municipal level, Kosovars should soon be permitted to choose their own leaders.