was a close connection between Hitler's foreign policy and anti-Semitic policies and that Hitler's decision to invade the Soviet Union in 1941 was linked to the decision to initiate the Holocaust. Hillgruber argued that the Kernstück (Nucleus) of Hitler's racist Weltanschauung (world view) was to be found in Mein Kampf. He believed that the Holocaust was meant to be launched only with the invasion of the Soviet Union. In Hillgruber's view, Hitler's frequent references to "Judaeo-Bolshevism", to describe both Jews and Communism, betrayed his desire to destroy both simultaneously. In Hillgruber's opinion, Operation Barbarossa had been conceived as, and was, a war of total extermination against what Hitler saw as "Judaeo-Bolshevik" system in the Soviet Union. Hillgruber was noteworthy as the first historian to argue for the connection between Operation Barbarossa and the decision to begin the Holocaust. In Hillgruber's opinion, for Hitler from about 1924 onwards:The conquest of European Russia, the cornerstone of the continental European phase of his program, was thus for Hitler inextricably linked with the extermination of these "bacilli", the Jews. In his conception they had gained dominance over Russia with the Bolshevik Revolution. Russia thereby became the center from which a global danger radiated, particularly threatening to the Aryan race and its German core. To Hitler, Bolshevism meant the consummate rule of Jewry, while democracy - as it had developed in Western Europe and Weimar Germany - represented a preliminary stage of Bolshevism, since the Jews there won a leading, if not yet a dominant influence. This racist component of Hitler's thought was so closely interwoven with the central political element of his program, the conquest of European Russia, that Russia's defeat and the extermination of the Jews were - in theory as later in practice - inseparable for him. To the aim of expansion per se, however, Hitler gave not racial, but political, strategic, economic and demographic underpinnings. According to Hillgruber, Hitler had four motives in launching Operation Barbarossa, namely: The extermination not only of the "Jewish Bolshevik elite" who supposedly governed the Soviet Union since seizing power in 1917, but also the extermination of every single Jewish man, woman and child in the Soviet Union. Providing Germany with Lebensraum ("living space") by settling millions of German colonists within what was soon to be the former Soviet Union, something that would have required a massive population displacement as millions of Russian Untermenschen ("sub-humans") would