THE U.S. GOVERNMENT'S posting of an up-to-$5 million reward for information leading to the capture and trial of Slobodan Milosevic and his fellow alleged war criminals is a welcome sign of seriousness. The International War Crimes Tribunal, a creature of the United Nations, is not out for revenge, and its indictments are not just a sidelight of the wars in Bosnia and Kosovo. Rather, the court's work represents a search for justice and accountability that is at the very center of what the Balkans need, and that should be at the very center of U.S. and NATO policy.

The Western powers haven't always behaved accordingly. Leaders indicted for some of the most reprehensible crimes of the Bosnia war remain at large, although NATO troops could apprehend them if they would attach greater importance to the effort. When the tribunal indicted Mr. Milosevic, the president of Yugoslavia, some U.S. officials privately regretted the action, believing it would prolong the war in Kosovo. That soon proved untrue; Mr. Milosevic essentially surrendered to NATO's demands despite, or perhaps even in part because of, the indictment and its attendant international isolation.

But even then, President Clinton spoke in a way that could give the impression that the U.S. government was less than fully committed to Mr. Milosevic's arrest. The indictment was proper, Mr. Clinton said, but "presumably he's beyond the reach of the extradition powers of the other governments." NATO's "heaviest responsibility," he added during his remarks in Paris nine days ago, was to help resettle the Kosovar deportees and promote autonomy and rebuilding for them. As to a trial for Mr. Milosevic, Mr. Clinton said, "Sometimes these things take a good while to bear fruit."

Sometimes they do; but the United States should do everything it can to make sure the trial will come soon, for Mr. Milosevic and the many other indictees still at large. U.S. involvement in the Balkans, Mr. Clinton has said many times, is intended to foster a climate in which people of different ethnic groups can live together peacefully and in which past crimes are expiated by bringing the guilty to justice, rather than by wreaking vengeance on anyone who happens to share an ethnic identity with the guilty. The latter principle is what we see in operation now as Kosovo Albanians burn down Serb houses. The former -- the principles of justice and accountability -- are what the international war crimes court is all about.

Trials could be critical, too, for helping Serbs and Croats come to terms with the sins of the past decade. Poisonous propaganda has inflamed nationalist passions and, especially in Serbia, fed a mythology of Serbs as perpetual victims. To counter that mythology, to face honestly the crimes committed not just by Mr. Milosevic but by innumerable followers, will not be easy. A sober trial in The Hague, with a full recounting of evidence and a fair role for the defense, could provide an invaluable assist.