Reasonable (adj.): Agreeing with whatever Rawls says for whatever reason.
E.g., "There are lots of different conceptions of the good life and of justice, but all reasonable people would agree that what Rawls happened to endorse in 1972 is legitimate."
Unreasonable (adj.): Good at political philosophy. Capable of making arguments for conclusions.
E.g., "Robert Nozick, Gil Harman, and Peter Singer are unreasonable because they are not Rawlsians, therefore we don't have to respond to their criticisms of Rawls."