This chapter analyses the decline of the concern about liberty as non-domination and the idea of a competition–democracy nexus following the ascent of the Chicago School and the rise of a More Economic Approach towards antitrust law on both sides of the Atlantic. It shows how the Chicago School not only challenged the economic foundations of the republican antitrust tradition but also put forward the consumer welfare standard as a versatile, principled framework to supersede the conception of republican liberty with a narrow negative notion of economic liberty as non-interference. The Chicago School thus shaped a laissez-faire approach to antitrust that seeks, in the first place, to preserve entrepreneurial liberty against state interference.