Arendt’s observation that Adolf Eichmann, rather than being an inhuman monster, was actually an ordinary man of at best average intelligence who believed the aberrant culture of Nazi Germany was completely normal and behaved accordingly, was regarded as radical, even heretical, in 1964. Events have proved her thesis sickeningly correct, (see, for example, Jared Kushner.) From the introduction of her masterpiece Eichmann in Jerusalem.:

Evil need not be committed only by demonic monsters but, with diastrous effect, by morons and imbeciles as well, especially if, as we see in our own day, their deeds are sanctioned by religious authority.

And here it is in the beautiful reading of Wanda McCaddon: