SS chief Heinrich Himmler referred to the war against the Soviet Union in an address to his men: “This invasion is an ideological battle and a struggle of races. Here in this struggle stands National Socialism—an ideology based on the value of our Germanic, Nordic blood… On the other side stands a population of 180 million, a mixture of races whose very names are unpronounceable, and whose physique is such that one can shoot them down without pity and compassion…” According to Himmler, what why did Nazi Germany need to wage this war?