This essay shows the continued value of Rawls’s public reason project. Its internal tendency is to generate new ideas. To do so, I review seven models of public reason, beginning with A Theory of Justice. Following Political Liberalism, I focus on Rawls’s unaddressed problem of justice pluralism. Rawls did not contain reasonable disagreement abou tjustice. Failing to stop it requires developing a fourth model of public reason. If Rawlsians accept justice pluralism, they must explore Gerald Gaus’s public reason project, so I introduce three models of public reason in Gaus’s work. The final model has only begun to bear fruit, generating a research program Gaus called the New Diversity Theory. Rawls and Gaus show that the public reason project remains a fertile research program

Rawls’s argument that a well-ordered society would be a social union of social unions is crucial to his larger argument for stability. The former argument depends upon what I call “the security assumption.” I contend that reasonable religious pluralism casts doubt on the assumption and on the argument which appeals to it. Seeing why the dubitability of the security assumption makes the idea of a social union of social unions non-viable, we can come to a better understanding of the development of Rawls’s thought. Equally if not more important is the relevance of the security assumption for contemporary politics. That assumption identifies a condition that must be satisfied if members of a liberal democracy are to find their collective activity as citizens inherently valuable. Failure to satisfy that condition suggests why some members of liberal democracies as we know them deny the inherent value of relations with their fellow citizens.