On 22 June 1941, the German Wehrmacht invaded the Soviet Union, and the Nazi regime embarked on its second, and far more ambitious, killing operation. Mobile operational units of the SS, the Einsatzgruppen of the Sipo and SD, crossed the Soviet border immediately after the battle troops. In the occupied territory of the Soviet Union, these units shot large numbers of civilians in mass executions.1 Their primary task was the murder of all Jews on Soviet soil.2 They also murdered all Gypsies and, wherever possible, the handicapped?3 The quartermaster of the German army, General Eduard Wagner, thus recorded in September 1941: "Russians consider the feebleminded holy. Nevertheless, killing necessary."4
The Germans labeled the murder of Soviet Jews, and the subsequent murder of all Jews within their jurisdiction, as the final solution of the European Jewish question (Endlæsung der europäischen Judenfrage).5 The term "final solution," used in the contemporaneous protocol of Reinhard Heydrich's Wannsee conference, has come to stand for the mass murder of Jews, although Hermann Gæring in his letter of authorization referred both to "final solution [Endlæsung]" and to "total solution [Gesamtlæsung]."6
Historians investigating Nazi genocide have long debated who gave the order to kill all Jews, when it was issued, and how it was transmitted.7 Even though the specific mechanism, including the approximate date, has been a matter of contention, there now appears to be general agreement that Hitler had a deciding voice, although no one has ever discovered, or is likely to discover, a smoking gun.
The chronology of Nazi killing operations provides a road map for those seeking answers to these questions. The murder of the handicapped preceded the murder of Jews and Gypsies, and it is therefore reasonable to conclude that T4's killing operation served as a model for the final solution. The success of the euthanasia policy convinced the Nazi leadership that mass murder was technically feasible, that ordinary men and women were willing to kill large numbers of innocent human beings, and that the bureaucracy would cooperate in such an unprecedented enterprise.
Just as race scientists, psychiatrists, and party ideologues had advocated killing the handicapped even before the killings commenced, German police officers and government administrators in the East proposed killing the Jews before the final solution started.8 But nothing so radical or unprecedented could be initiated without Hitler's approval. There is no reason to believe that