ARUSHA, Tanzania -- When Canada's Gen. Romeo Dallaire gave his testimony last month, he could not hold back tears.
Wiping his eyes with a handkerchief, Dallaire described scenes of horror and his own powerlessness as Rwandan killers in 1994 unleashed one of the worst mass crimes since World War II -- three months of systematic slaughter that left nearly a million people dead.
For the general, who was the U.N. peacekeeping commander in Rwanda during the genocide, blame lay with the international community for not stopping the killing. If only the United Nations had given him more troops and a mandate to intervene, he said, "hundreds of thousands of lives" could have been saved.
The testimony was some of the most dramatic since the International War Crimes Tribunal for Rwanda was established in this town in northern Tanzania more than three years ago.
It also poked at a question at the heart of the tribunal's existence: How should the world respond to massive crimes against humanity, ones that violate international law designed to discourage such crimes in the first place?
Unwilling to stop the Rwandan genocide while it happened, the United Nations created the war crimes tribunal after the slaughter was over. The idea was to bring to book the masterminds of the genocide and to offer a traumatized nation some sense of justice.
In so doing the tribunal has taken on what the court's Senegalese president, Laity Kama, calls a "historic mission" aimed ultimately at discouraging killers from mass slaughter.
The Rwandan government has about 120,000 genocide suspects locked up, awaiting action by its own overmatched investigators and prosecutors, who have conducted about 350 trials so far. A third of the defendants were sentenced to death, but none of the sentences has been executed.
Twenty-three men accused of being ringleaders, including the former prime minister and defense minister of the Hutu-dominated government that conducted the genocide, were captured in Europe or Africa and extradited to the international tribunal here.
It will be the first international criminal court to interpret the definition of genocide, which was set out in a 1948 convention signed in Geneva. It will, in the words of one court official, "provide the legal lamppost on genocide."
This tribunal, and one for the former Yugoslavia, are the first international war crimes courts to be independently established. Their precedent, Nuremberg, was created by World War II's winners. The Yugoslavia and Rwanda tribunals were established the United Nations.
