Hayek was one of the leading academic critics of collectivism in the 20th century. Hayek argued that all forms of collectivism (even those theoretically based on voluntary co-operation) could only be maintained by a central authority of some kind. In Hayek's view, the central role of the state should be to maintain the rule of law, with as little arbitrary intervention as possible. In his popular book, The Road to Serfdom (1944) and in subsequent academic works, Hayek argued that socialism required central economic planning and that such planning in turn leads towards totalitarianism.