Pope Pius XII's alleged silence in the face of the destruction of the European Jews during World War II has been the subject of a fierce controversy that has continued unabated ever since Rolf Hochhuth's The Deputy made the charge in 1963. Numerous critics have accused Pius of everything from deliberate anti-Semitism to collusion with the Nazi regime, while equally partisan defenders have argued that his silent diplomacy saved hundreds of thousands of Jews and other innocent victims from Nazi terror. So contentious has Pius' role become that the phrase the silence of Pius XII has taken on a...