Radovan Karadzic, accused of ordering some of the worst atrocities in Europe since World War II, is still tormenting his victims. More than 160 Bosnian Muslims traveled to the Hague for the start of the former Bosnian Serb leader’s war crimes trial on Monday only to have him boycott the proceeding.

Judges with the International Criminal Tribunal for the former Yuogoslavia adjourned the session and promised to begin on Tuesday with or without Mr. Karadzic in the dock. The trial must go ahead. After so many years of anguish, the relatives of the thousands of who were killed deserve a chance at justice.

It took 13 years and enormous international pressure to persuade Serbian authorities to finally arrest Mr. Karadzic. (He was living in Belgrade posing as a New Age healer.) He faces 11 charges of war crimes and genocide, for his role in the 43-month siege of Sarajevo, the massacre of 8,000 Muslim men and boys at Srebrenica and the so-called ethnic-cleansing campaign against Bosnian Muslims and Croats.

Slobodan Milosevic, the murderous former Yugoslav leader, played similar games with the war crimes court for four years, only to die of a heart attack before a formal verdict was rendered. Mr. Karadzic seems equally determined to mock the court and draw things out. He refused to send a lawyer to Monday’s hearing, refused to enter pleas, demanded more time to prepare for trial and — unsuccessfully — claimed immunity from prosecution, asserting that he had cut a deal with the former United States peace envoy, Richard Holbrooke, in 1996. Mr. Holbrooke has denied this. The court must accord Mr. Karadzic appropriate rights, but it cannot let him control the process...