In Political Liberalism, Rawls argues that the exact theory he came up with in 1972 would be what an overlapping consensus of reasonable people would agree to. Reasonable people are defined by....well, ask 20 political liberals what makes someone reasonable and you'll get 40 answers. But in one way or another, reasonable people are committed to the idea of public reason itself--that all principles be in some way justifiable to the reasonable (damn recursion/reflexivity!) subject to those principles on grounds they can in some way endorse or recognize given their diverse epistemic and moral standpoints--and to the idea that politics must respect us as free and equal.
But over on Twin Earth, Twin John Rawls at Twin Harvard took a decidedly more Schmittean turn. (He ended up being a more consistent, less question-begging theorist as a result, if not closer to the truth.) On Twin Earth, Twin Rawls discussed how there might be an overlapping consensus of illiberal authoritarians. He called his book Political Illiberalism.
Liberals disagree about what exactly justice requires, what the good life is, and so on. But they agree that society should treat people as free and equal.
Well, Twin Rawls points out that in the same way, illiberal authoritarians--such as tankies, Nazis, fascists, illiberal theocrats, and others--disagree about what exactly justice requires, what the good life is, and so on. But they also agree on lots of things. They agree that societies ought to be hierarchical. They agree that society takes precedence over the individual. They agree that what makes something legitimate is that it can be justified to, and be the subject of an overlapping consensus of, people committed to the idea that people are unfree and are unequal. On Twin Earth, for instance, when collectivist authoritarians, religious fundamentalists, and so on, disagree about many specific details of their politics, they often defer to reliable umpires to determine which kind of authoritarian, totalitarian, or intrusive politics they ought to have.
On our Earth, John Tomasi at Brown published a book called Liberalism Beyond Justice. He describes people as falling into four categories from he standpoint of public reason theory. A-people are ethical and political liberals who value openness, individuality, and so on. Think Ayn Rand and John Stuart Mill. C-people are reasonable romantics and religious people who adhere to more conventional, traditional, and hierarchical ways of life, but who are nevertheless committed to the public reason project and so keep their religiosity out of politics. Think Kevin Vallier. B-people are the typical wishy washy people in between. Think Rawls himself. But then there are D-people, who reject the public reason project altogether in favor of imposing hierarchical, illiberal political policies, regardless of whether those positions can be justified on Rawlsian grounds, whatever that means. They are considered unreasonable and the system does not need to be justified to them.
On Twin Earth, Twin John Tomasi at Twin Brown published a book called Illiberalism Beyond Justice, which also had a helpful alphabet soup characterization of people. Twin Tomasi's A-people are committed collectivist authoritarians. Think Stalin. His C-people are fairly individualist people who advocate as much liberalism for themselves as the theory allows, but who defer overall to the illiberal public reason project. Think Sartre. (Remember, Sartre was a tankie.) B-people are the wishy washy in-between people. D-people are political liberals who reject the overlapping consensus of illiberal public reason. They are considered unreasonable and the system does not need to be justified to them.
On earth, when someone who is not a public reason liberal--e.g., a regular old liberal or libertarian--criticizes Rawls, Rawlsians are inclined to dismiss the person as unreasonable. The same thing happens on Twi Earth. For instance, if you complained that Twin Rawls's theory treats people as unfree, you'd be dismissed as unreasonable and your criticism ignored.
I, Jasper, having read both liberal and illiberal Rawls defend exactly the opposite theories on what are almost identical grounds, can't find a particular reason to reject liberal Rawls as having a better argument than illiberal Twin Rawls. The theories are structurally identical and generate the opposite result. I guess people will just pick and chose Rawls over Twin Rawls because they like the conclusions, not because the theories are any better. Rawls starts with liberal assumptions and gets liberal conclusions. Twin Rawls starts with illiberal assumption and generates illiberal conclusions through a mirror-image but structurally identical theory.
I got bad news for you, folks. Not only is there Twin Rawls, but Triplet Rawls, Quadruplet Rawls, and more. Turns out you can recast Rawls's public reason project any way you want, with any political philosophy you want being the subject of an overlapping consensus of "reasonable" people suitably and plausibly defined. Oh well.