Hayek, Samuelson, and the logic of the mixed economy?

In 1980 Friedrich Hayek wrote to Paul Samuelson complaining about the role that Economics had played in discrediting the thesis of Hayek's The Road to Serfdom. In the 11th edition of Economics, Samuelson had written that "each step away from the market system and towards the social reform of the welfare state is inevitably a journey that must end in a totalitarian state." Given the apparent prevalence of this reading of Hayek's thesis, we assess the dispute over Hayek's 'inevitability thesis' and whether Hayek's complaints were justified.