There is a fable that persists in even themost respectable quarters, perhaps because it has retained its power to shock for more than half a century. Get any card-carrying liberal into a sufficiently confessional mood and she will tell you, sotto voce, that there was one domain in which the Nazis were perversely and chillingly formidable: the domain of the aesthetic.

Even the Nazis’ detractors hailed their movies as sensations. Most famously, Susan Sontag noted in her landmark essay “Fascinating Fascism” that Nazi uniforms bristled with sex appeal, that the films of Leni Riefenstahl had a curious allure. Thus Walter Benjamin and a generation of subsequent theorists argued that fascism was, at its core, an all-too-successful effort to aestheticize politics.

In this telling, the problem was not that the Third Reich was too vulgar or too mawkish; on the contrary, it was too coolly sophisticated—so much so that it framed the violence it wrought as weightless spectacle.…