There was a lesser and a greater Second World War. Hitler started the first of the two in September 1939 in an attempt to conquer Europe by defeating opposing armies piecemeal in short Blitzkrieg campaigns in which the tank, supported by mechanized infantry, was the main element of attack. To wage warfare on this scale was not economically painful for the Reich. Though stocks of raw materials had to be built up and national self-sufficiency increased in fuel and other war-critical supplies, it was only necessary to mobilize industry and agriculture partially; guns and butter could be kept in reasonable equilibrium and battle done with the technologies of the past. Hitler did not have to reorganize Germany in order to sustain a new type of combat; however radical his aims, his approach to waging war was socially conservative. The United States launched the greater war in summer 1940, actually a year and a half before either of the two simultaneous strategic turning points, the Japanese attack on Pearl Harbor and the Wehrmacht's defeat at Rostovon-Don, had been reached. The American war against fascism was total in character: global, fought in the air and at sea as much as on land, technology-driven, and potentially revolutionary in its political, social, and economic implications. Success in this greater war depended less on diplomatic or military strategies than on vast industrial and agricultural power that made it possible to conduct hostilities on a scale far more immense than anything Hitler could have imagined in 1939.