Six months ago, Prof. Gideon Greif was on top of the world. A respected Holocaust scholar, he was set to receive Germany’s highest civilian honor for his research on the Sonderkommandos, Jewish prisoners who were forced to dispose of bodies at the Nazi death camps. Years earlier his research was adapted into an award-winning feature film, "Son of Saul." But the civilian honor in Germany was soon rescinded amid allegations that Greif was a genocide denier who tried to whitewash the murder of 8,000 Bosnian Muslim men and boys by Bosnian Serb forces at Srebrenica in July 1995. Now the...