The foundation of Nazism was not Darwinism, but immunology. Hitler believed he was the "Robert Koch" of Germany who had discovered the source of the nation's disease. On February 22, 1942 he declared:

The discovery of the Jewish virus is one of the greatest revolutions that has taken place in the world. The battle in which we are engaged today is of the same sort as the battle waged by Pasteur and Koch. How many diseases have their origin in the Jewish virus! We shall regain our health only by eliminating the Jew.

This fantasy was the source of--was enacted as--the Final Solution

The objective of National Socialism was to remove the Jewish virus from within Europe, the Soviet Union, and eventually the entire world. This was Hitler's dream, a rescue phantasy, the dream of saving the world by destroying the source of the world's illness. 

Hitler attacked the Soviet Union--not as the desire for "conquest" (the word does not appear a single time in Hitler's writings)--but in order to destroy the root cause of Germany's disease: "Jewish-Bolshevik bacteria" that Hitler believed were "seeping in" from the East.

Nazism was a revolutionary movement whose purpose was to destroy the Jews, conceived as oppressive, omnipotent and virulently destructive. The Final Solution and war against the Soviet Union were two sides of the same coin with the same purpose: to overthrow a group of people that Hitler imagined was intent upon destroying Germany and Western Civilization. 

We say that Hitler "lost" the war and in a certain sense, obviously, this is true. But in another sense, Hitler didn't see it this way. At the very end, in his Final Testament, he declared: "We have lanced the Jewish ulcer, and the world will be entirely grateful to us."