Related Ideas

Rawls is usually understood to give liberty a priority over other concerns. The first principle of justice guaranteeing everyone the largest possible set of equal liberties is given priority over the second principle. This priority prevents tradeoffs that would restrict the liberty of some for the sake of other advantages such as rapid economic growth. It would, for example, preclude slavery even if it could be shown to maximize the accumulation of wealth. For this reason, Rawls' views are often contrasted with some versions of utilitarianism.

A closer reading of Rawls reveals that under some circumstances the priority of liberty is not guaranteed. He defines both a "general" and  "special" conception of justice; and it is only the special conception that assigns a lexical priority to liberty. In some cases, he tells us, "it may be reasonable to forgo part of these freedoms when the long-run benefits are great enough to transform a less fortunate society into one where the equal liberties can be fully enjoyed. This is especially true when circumstances are not conducive to the exercise of these rights in any case." [Theory, sections #11, 39, and 82] In these circumstances, only the general conception of justice applies. For example, Rawls writes:

The supposition is that if the persons in the original position assume that their basic liberties can be effectively exercised, they will not exchange a lesser liberty for an improvement in their economic well-being, at least not once a certain level of wealth has been attained. It is only when social conditions do not allow the effective establishment of these rights that one can acknowledge their restriction. The denial of equal liberty can be accepted only if it is necessary to enhance the quality of civilization so that in due course the equal freedoms can be enjoyed by all. The lexical ordering of the two principles is the long-run tendency of the general conception of justice consistently pursued under reasonably favorable conditions. Eventually there comes a time in the history of a well-ordered society beyond which the special form of the two principles takes over and holds from then on. [Theory, section #82]

David Lyons discusses this aspect of Rawls' theory and argues that the contrast with utilitarian theory is not as sharp as is usually supposed. H. L. A. Hart also discusses the priority of liberty and poses objections to Rawls' views. In particular, he criticizes the claim that under favorable conditions (to which the special conception of justice applies) liberty can only be restricted for the sake of liberty.

Rawls does not dwell on the possibility of trading off liberty for other benefits, perhaps because he was primarily concerned to develop an ideal theory of justice and, furthermore, one that would apply best to affluent democratic societies like the United States. However, in some of his later work, he suggested that justice also requires that the basic needs of all citizens be met.

The constitutional essential here is rather that below a certain level of material and social well-being, and of training and education, people simply cannot take part in society as citizens, much less as equal citizens. [Political Liberalism, p. 166.]

Reference: See papers by David Lyons and H. L. A. Hart in Reading Rawls edited by Norman Daniels.