Obviously not personally, no. Darwin would probably have been appalled at the use that Hitler put his ideas to. But I nevertheless think that it is reasonable to connect the dots of evolutionary theory to Adolf Hitler’s ideology, yes. I do not mean that evolution leads, of necessity, to fascism; I mean that in one historical instance—Nazi Germany—evolutionary science’s sheen of respectability morphed into a noxious ideology, and in its use by Hitler was turned in Germany into a form of scientism.
I also think it is obvious that Hitler’s ethic is derived from his reading of German eugenicists, probably most earnestly Ernst Haeckel. Hitler was a syncretist, no doubt. There were lots of creepy disconnected sugar plumbs dancing in his head, but the chief of those was struggle, survival of the fittest. He read out of the theory of evolution by struggle “the law of Nature.” Please recall that Hitler called his manifesto, Mein Kampf—not Turn the Other Cheek. And Hitler may not have mentioned Darwin in his book, but he does use the word evolution. He thought his goal was “preserving the best humanity, to create the possibility of a nobler evolution of these beings.” I didn’t, by the way, scan Mein Kampf to find that quote. It is in the historian Richard Weikart’s new—and very good—book on Hitler titled Hitler’s Ethic (Palgrave Macmillan 2009, p. 6). Evolution as absorbed by Hitler in its simplest form (survival of the fittest by an eternal and universal law of constant struggle) gave him the opportunity not just to be a fascist, but an intellectually fulfilled fascist. The “law of evolution” gave his ideas the superficial appearance of being “scientific” and therefore, to his mind, inevitable.
Hitler’s fascism was thus a form of scientism. It added a metaphysical component to evolutionary science. Of course, this is what Richard Dawkins and Daniel Dennett have done as well, overlaying evolution with their own big leap of faith—their own metaphysical conclusion. That great leap is a strict materialist metaphysic—atheism. They have then declared evolution the engine of their atheism and “a universal acid” (in the same way that Hitler declared “the iron law of struggle” to be universal and the engine for the inevitability of his own ideas). This is not to say that Dawkins and Dennett’s form of atheist humanism is anything like as noxious an idea as Hitler’s fascism. But in their hands it is a form of scientism, and not science. It is the governing (and, I would argue, overly simplistic) formula for their thought. It is applied everywhere. Nothing escapes it. Not even free will.