“Public reason” is the name that Rawls gives to the shared form of reasoning that the citizens of a pluralist democratic society should use when deciding constitutional essentials and questions of basic justice. Public reason not only makes the realization of the ideal of fair social cooperation amongst free and equal citizens possible in pluralist societies; according to Rawls, it should be understood as “part of the idea of democracy itself” (PL 441). By employing public reason when deciding fundamental political questions, citizens relate to one another as equal co-sovereigns and ensure the legitimacy of their shared exercise of political power. Political power in an adequately just liberal society, Rawls writes, “is ultimately . . . the power of free and equal citizens as a collective body” (PL 136; cf. xliv, 445). In order to exercise political power in a genuinely shared manner, citizens need to provide mutually acceptable justifications for that exercise. The terms of public reason provide such mutually acceptable justifications. In addition to being co-sovereigns, citizens also are related to the institutions of their society’s “basic structure” as subjects, as they cannot exempt themselves from the demands of those institutions. The institutions of the basic structure determine the shape of citizens’ freedom by specifying and protecting their basic liberties, distributing opportunities and resources, and so forth. Because citizens are conceived of as free and equal, such determinations need to be justifiable to them. Once again, the terms of public reason provide such justifications.