Public choice theory is an approach to political science that employs assumptions and models common in economics. It analyzes politicians and other political actors as (largely) self-interested agents. Public choice economics arose in response to the work of economist Duncan Black but was made famous by James Buchanan and Gordon Tullock in their well-known The Calculus of Consent: Logical Foundations of Constitutional Democracy (1962). Early in his career, Rawls communicated with Buchanan on a number of matters. Rawls always considered himself an admirer of Buchanan’s work (for the text of the Rawls–Buchanan correspondence and commentary, see Peart and Levy 2008, 395–415).

Nonetheless, Rawls thought that the insights of public choice did not apply to the selection of principles of justice. Instead, if public choice analysis was sound, it was relevant only to the implementation of justice in the second “constitutional stage” of Rawls’s four-stage sequence. In his 1963 article, “Constitutional Liberty and the Concept of Justice,” Rawls distinguishes his approach from Buchanan and Tullock’s because “they are mainly concerned with that part of constitutions having to do with legislative procedure…” (CP 74 n.1). Rawls argues in TJ that Buchanan and Tullock misunderstand the conditions of constitutional choice. On Rawls’s view, “[t]he idea of the four-stage sequence is a part of a moral theory … the aim is to characterize a just constitution and not to ascertain which sort of constitution would be adopted, or acquiesced in, under more or less realistic (though simplified) assumptions about political life, much less on individualistic assumptions of the kind characteristic of economic theory” (TJ 173 n.2). Here Rawls denies that public choice economics applies directly to his second-stage. Instead, he sees the Buchanan–Tullock conception of constitutional choice as amoralist and excessively individualistic.