"In private correspondence, Nisbet took his own views even further, claiming Rousseau to have been “the real demon in the modern mind” and “the most malevolent genius of the whole modern era.” Had Rousseau not existed, the famous sociologist continued, there would have been no Lenin, no Stalin, and no Hitler.
Jean-Jacques Rousseau has long been the bête noire of the conservative movement and for good reasons. In his own works—but especially in his Rousseau and Romanticism—Irving Babbitt offered a criticism comparable to that of Nisbet, but a full generation earlier. Russell Kirk, Eric Voegelin, and William F. Buckley had no love for Rousseau either.
Conservative criticism of Rousseau, though, began over two centuries ago, with Edmund Burke’s public attack on him in 1791, correctly identifying him as the touchstone of the French Revolution."