David Gordon in The American Conservative:
Rawls never abandoned the principal tenets of his theory of justice, but in his 1993 work Political Liberalism, he changed course in one respect. He began emphasizing that in modern constitutional democracies like the United States, disagreements over fundamental values and issues such as abortion can threaten the stability of society. Given the degrees of disharmony, what are we to do?
His answer recalls the original position of TJ. Individuals should, once more, put aside their own conceptions of the good. But this time, in deliberating on these divisive issues, people must rely only on “public reason.” This consists of principles that everyone, regardless of his conception of the good, will have cause to accept. By an odd coincidence, if public reason is used properly, we will arrive at exactly the same principles as those set forward in TJ. It is difficult not to wonder whether Rawls’s enterprise is merely an attempt to find arguments in support of the political opinions of professors of his social class.
An example will show how public reason works. If your religion forbids abortion, you cannot appeal to this fact in political discussions, since religious views do not form part of public reason. Later, Rawls modified this rigid view. His final position was that you could mention your private views as long as you also had an argument from public reason to support your stand. Rawls’s introduction to the 2005 paperback edition of Political Liberalism states, “Certainly Catholics may, in line with public reason, continue to argue against the right of abortion. That the Church’s nonpublic reason requires its members to follow its doctrine is perfectly consistent with their following public reason.”
Even with that concession, Rawls’s idea of public reason has little to recommend it. Rawls has simply defined a notion of social stability to suit his theory. He never shows that something bad will happen if a society is not “stable” in his sense. Why cannot a society like our own, with considerable religious and philosophical disagreement, continue to flourish without the crutch of public reason?