She fought Cosa Nostra in Italy (and barely escaped being blown to bits in 1988 for her efforts). She took on the Russian Mafia and the legendary banking secrecy laws of her native Switzerland, where she rose to the top law-enforcement job in the land. But all that was just the prelude. In five years as the chief prosecutor at the International Criminal Tribunal for the Former Yugoslavia in the Hague — the most important war-crimes court since Nuremberg — Carla del Ponte has pursued and brought to justice some of the world's most dangerous men.

Now, as the trial of ex–Serbian President Slobodan Milosevic on charges of genocide and crimes against humanity enters its critical final phase, Del Ponte, 57, has become the world's most visible champion of justice for the victims of war. "She is a relentless fighter against the obstruction of justice," says Natasa Kandic, Serbia's leading human-rights investigator and head of the Humanitarian Law Center in Belgrade (and a Time European Hero in 2003). "She doesn't behave like a diplomat, but that is because she is not a diplomat. Her job is not to exchange pleasantries but to enforce the rule of law."

Standing barely 1.52 m tall, Del Ponte is a chain smoker with a taste for Christian Dior. She wanted to follow her two brothers into medicine, but chose law instead. After a short time as a defense attorney, she felt more suited to prosecution. "She didn't believe her clients were always innocent," said an aide.

Del Ponte has berated Presidents, faced off with nato commanders and been subjected to a torrent of abuse. (Milosevic called her "the new Gestapo"; the Sicilian Mafia dubbed her "La Puttana" [the whore].) She has a round-the-clock bodyguard and does her weekend shopping in a bulletproof car. Yet she has completed 47 indictments since taking the job in 1999. She is an equal-opportunity prosecutor, bringing charges against not just Serbs, but also Croats, Bosnian Muslims, Kosovars and, in her position as prosecutor for Rwanda, Hutus and Tutsis. She even considered — briefly — charges against the nato alliance for allegedly targeting civilians during the Kosovo campaign. Asked how she would convince critics who complained that she dropped that investigation because of favoritism toward the West, she replies, characteristically: "I don't have to convince anybody — only myself."

Her record is not flawless. The Milosevic trial is running into serious complications thanks in part to her insistence that he stop grandstanding for the TV cameras. Her abrasive style has alienated some allies. Yet she has used her position more effectively than her predecessors to shame local leaders into respecting the court's jurisdiction. Bosnian Serb leaders Radovan Karadzic and Ratko Mladic are still at large, but it's not her job to chase them. While the Hague Tribunal is expected to wrap up its work in two years, the sharp-tongued Swiss prosecutor's energy and determination will live on — perhaps even in the minds of future war criminals weighing their next crime.