The trouble with Eichmann was precisely that so many were like him, and that the many were neither perverted nor sadistic, that they were, and still are, terribly and terrifyingly normal. From the viewpoint of our legal institutions and of our moral standards of judgment, this normality was much more terrifying than all the atrocities put together, for it implied — as had been said at Nuremberg over and over again by the defendants and their counsels — that this new type of criminal, who is in actual fact hostis generis humani, commits his crimes under circumstances that make it well-nigh impossible for him to know or to feel that he is doing wrong.

Hannah Arendt (1906-1975) German-American philosopher, political theorist
Eichmann in Jerusalem: A Report on the Banality of Evil, Epilog (1963)