This case will focus mainly on crimes in one country, as opposed to the Milosevic case, which was enormous in its scope, dealing with wars in three countries and spanning a decade.

The evidence, experts say, is also much clearer.

Mr. Karadzic, even before the outbreak of war in Bosnia, often declared publicly that his mission was to “protect” Christian Serbs from Bosnian Muslims threatening to create an Islamic state. He made virulent speeches, warning that if Bosnia broke away from Yugoslavia, its Muslim population could be decimated.

Image The former Bosnian Serb leader Radovan Karadzic appeared before the international war crimes tribunal for the former Yugoslavia on Thursday for the first time.

After the war, the Bosnian Serb forces under his command destroyed many military records, but NATO troops swept through army barracks and police stations and nonetheless seized thousands of documents. The prosecution has reams of material presented at the tribunal in almost two dozen other cases related to Bosnia. Forensic experts have dug up mass graves. There are intercepts of telephone and radio conversations between Mr. Karadzic and top politicians and commanders.

“Karadzic was closer to the action than Milosevic,” said Geoffrey Nice, the former lead prosecutor in Mr. Milosevic’s trial. “He was there, he was vocal, he was in charge. Milosevic was contributing from afar, through political and military support. Karadzic used explicit and damning language in his public speeches. I don’t know if it is enough, but it’s very powerful.”

For the court, much is at stake in the trial of this new high-profile defendant, who will be judged as the tribunal, created in 1993 by the United Nations Security Council, moves toward closing down. Some see it as a chance for the tribunal  often criticized for plodding and overcomplicated cases, Mr. Milosevic’s in particular  to enhance its record.

“With Karadzic coming in, it is a lot easier for the tribunal to make a strong and lasting impact,” said David Kaye, who followed the court as an American diplomat in The Hague and now teaches law at the University of California, Los Angeles. “This is the chance to tell the full story of what happened in Bosnia. Karadzic had the overall vision, the command structure and the direct responsibility for wartime events.”