It often happens in the history of thought that philosophers come belatedly to a popular theme and attempt to make it serve new purposes. They volunteer to articulate intuitive sentiment and to make implicit dilemmas explicit. And they take what emerged as partisan slogans and determine whether to raise them to the level of philosophical claim. Just as regularly, however, the discourse that stimulated the thinkers proves stronger than their innovations. It is not, after all, as if the public noise around concepts, especially new ones, is stilled when the philosophers turn to canonize them. Hannah Arendt and Claude Lefort, the most serious theoreticians of what appeared to so many as a novel and unprecedented phenomenon of “totalitarianism” in the last century, attempted to make an extant discourse rigorous. They developed proprietary approaches that reshaped a popular intellectual discourse. To an impressive extent, however, their interventions did more to amplify the impact and to extend the longevity of the popular theories of “totalitarianism” they dearly hoped to reorient.