FOR THE FIRST TIME IN 50 YEARS, AN accused war criminal stood before an international tribunal to enter a plea last week. Flanked by two guards, Dusan Tadic, a Bosnian Serb cafe owner and karate enthusiast, took his place behind a wall of bullet-proof glass in a specially built, high security courtroom in the Hague. Responding to charges that he murdered, beat, raped and tortured Muslim and Croat prisoners in Serb-run camps in Bosnia, Tadic pleaded not guilty. He told the three-judge panel, "I was not present when these crimes were committed." The atrocities occurred during 1992, and prosecutors were eager to go to trial. But Tadic's court-appointed defender asked for a delay, arguing that he had been unable to locate witnesses while fighting continued in Bosnia. He was granted a six-month postponement.

Although Tadic is the only one of the 43 people indicted for war crimes in Bosnia who is actually in the tribunal's custody, his appearance in court signaled that the U.N.-created International Criminal Tribunal for the former Yugoslavia was swinging into action. There is no legal connection between the tribunal and the peace talks this week, but the Presidents of Bosnia, Croatia and Serbia might well be looking over their shoulders at it. Chief prosecutor Richard Goldstone, who earned a reputation for implacability when he investigated violence in South Africa, has vowed to go after the leaders who ordered the crimes to be committed or failed to stop them. So far the tribunal has indicted 42 Serbs and one Croat. Its nine teams of investigators are still at work, and additional indictments are promised, probably to add more Croats and some Muslims. Already indicted for war crimes including genocide are such senior figures as Bosnian Serb leader Radovan Karadzic, his military commander General Ratko Mladic, and Milan Martic, leader of the Croatian Serbs. The ethnic Croat under indictment is Ivica Rajic, a former captain in the Yugoslav army. He is charged with ordering the destruction of the village of Stupni Do and directing the killing of at least 16 of its Muslim residents. Since the Bosnian Serbs do not accept the tribunal's jurisdiction and will not cooperate with it, how are the accused to be brought to justice? The court is making a start through proceedings under its Rule 61. While there is no provision for trials in absentia, this rule allows something very similar. Prosecutors can present their case against the accused and, if the judges find it reasonable, they can "reconfirm" the indictment. They then issue an international arrest warrant, which requires U.N. member states to take the fugitive into custody and turn him over to the tribunal. That may not threaten the indictees who remain at home, but it will make international travel risky for them.

The court has already started down this road, which it says allows the world to hear "the voices of the victims." Earlier this month, 15 witnesses appeared over five days at a hearing to testify against Dragan Nikolic, reputedly the Bosnian Serb commander of a detention camp in northeast Bosnia, who is accused of murdering at least eight Muslims and torturing 10 others. The witnesses gave horrifying accounts of beatings with clubs, rifles and chains. Nikolic is believed to be at large in Bosnia, and one of the victims was so afraid of retaliation that he testified from behind a screen. The judicial panel in this case ruled that "there are reasonable grounds for believing that Dragan Nikolic committed the offenses," and issued an international arrest warrant.

The prosecutors do not announce their plans in advance, but there is little doubt they will keep going with Rule 61 proceedings against more of the accused war criminals who have been indicted but are not in custody. In due course they will probably take on Karadzic and Mladic. "The indictments," says Nicholas Burns, a U.S. State Department spokesman, "have been a great asset" because they allowed Serbian President Slobodan Milosevic to "freeze out Mladic and Karadzic" and take over the negotiations.

The pace of the tribunal's activity is expected to increase--provided it stays in business. Officials of the so-called Contact Group negotiating peace in Bosnia discount recurrent rumors that amnesties or the court itself could be used as bargaining chips for Serb or Croat concessions. "There's absolutely no possibility of eliminating the tribunal," says a U.S. official. Nevertheless, its future is seriously threatened by money problems. The court is already very strapped for cash and cannot be sure it will receive the $28.4 million the U.N. promised for this year. U.N. restrictions on travel, the judges warned this month, could "cut the very heart from the tribunal." If those funds dry up, even the worst of the war criminals will have nothing to worry about.

--Reported by Tamala M. Edwards/Washington, James Geary/The Hague and Nina Planck/Brussels