This is the boldest statement from a serious thinker that I’ve read today (from Russell’s 1945 book The History of Western Philosophy):
Ever since his [Rousseau's] time, those who considered themselves reformers have been divided into two groups, those who followed him and those who followed Locke. Sometimes they cooperated, and many individuals saw no incompatibility. But gradually the incompatibility has become increasingly evident. At the present time, Hitler is an outcome of Rousseau; Roosevelt and Churchill, of Locke.