One of the dominant themes in John Rawls' later philosophy is the idea of public reason. It does not signify simply one political value among others. In his view, public reason envelops all the different elements that make up the fabric of a constitutional democracy:

Clearly the idea of public reason therefore means more than just that the principles of political association ought to be an object of public knowledge. It has to do with the very basis on which collectively binding decisions are to be established. We exercise public reason, Rawls believed, when we bring our own reason into accord with the reason of others so as to develop a common point of view for settling the terms of our political life. The conception of justice by which we live is then a conception we endorse, not for the different reasons we may each discover, and not simply for reasons we happen to share, but instead for reasons that count for us because we can affirm together. In this undertaking is expressed that spirit of reciprocity that for Rawls makes up the foundation of a democratic society.