How Evil Works reviews The Dictators: Hitler’s Germany, Stalin’s Russia by Richard Overy:
The crudity of Hitler’s genetics, the patent falsity of Lysenko’s experiments, their visions of “world domination” — all seem ludicrous in hindsight. Recordings of Hitler’s speeches make him appear laughable, hysterical, absurd. Looked at now, Stalin’s kitsch propaganda films seem like parodies. Yet it is clear from archives, from memoirs, from recollections, that very few people were laughing at the time. The propaganda, the education, the parades, the spectacles, the falsified history, the marble statues, the Socialist Realist novels: they worked.
Both regimes treated pseudo-science as an infallible new religion:
The science itself was very different in Soviet and Nazi society, in other words, but its function was essentially the same. The supposed neutrality and incontrovertibility of scientific doctrine gave both regimes a good part of their intellectual legitimacy. Science, or rather pseudoscience, gave people a moral justification for behavior that had formerly been unthinkable. German concentration-camp guards, convinced that their Jewish prisoners were biologically inferior humans, had few qualms about murdering them. Soviet concentration-camp guards, convinced that their political prisoners were flawed humans who had to be re-educated through hard labor, saw nothing wrong with mistreating them, even if they died in the process.