For MPS members, the issue of monopoly loomed so large primarily because of the way their opponents on the left had framed it. The left had been arguing that since the start of the twentieth century monopoly had been expanding apace throughout the United States and Western Europe, such that the bulk of the economy—owing to this inexorable growth—would inevitably soon be controlled by monopolies. The left predicted that the forces of competition would continue to prove ineffectual in the face of such growth. Consequently, they insisted that the only rational solution was socialist control of the economy. This tenet of the program of the left threatened the very cogency of liberal optimism and was one of the major motivations for the MPS liberals to rethink liberal doctrine.

Philip Mirowski & Dieter Plehwe (eds.), The Road from Mont Pèlerin, loc. 1074