Both Hegel and Marx appear committed to the idea that the Reign of Terror was in some sense necessary. I argue that Hegel explains this necessity in terms of the concept of ‘absolute freedom’, together with the associated self-conception and normative picture of the world. It will be argued that Marx also views the Reign of Terror as necessary because of an abstract conception of political freedom and the citizen which conflicts with a determinate individuality that is characterized by particular interests and identities. In connection with Marx’s critique of Hegel’s theory of the modern state I draw attention to a puzzle, the discussion of which will lead to a brief account of how Marx’s attempt to overcome the opposition between the state and civil society differs from Hegel’s.