The chief prosecutor at the U.N.s war crimes tribunal called this week for a defense attorney to be imposed on Slobodan Milosevic. The deposed Yugoslav dictator, who stands accused of genocide in the Balkan wars of the 1990s, refuses to speak to his court-appointed lawyers and has been conducting his own, often loud and combative, defense. But the strain of cross-examining his enemies and poring over the hundreds of thousands of pages of evidence against him has harmed his health. The 61-year-old has several times delayed the proceedings for weeks because of exhaustion. Chief prosecutor Carla del Ponte said that, to spare the defendant and speed up the trial, a real attorney should take over. In Yugoslavia, she pointed out, Milosevic would be forced to have a lawyer.