The 300th anniversary of Jean-Jacques Rousseau was marked a few days ago.  As with the French Revolution he inspired (at least in part), opinion remains divided.  In 1952 the Israeli scholar Jacob Talmon showed that the Swiss thinker's idea of the general will was the basis for totalitarian populism, something that in Marxist and other guises has blighted the 20th century.

For a more positive view, see http://crookedtimber.org/2012/06/27/happy-birthday-jean-jacques/