Justice as Fairness was released in the final years of Rawls’ life and gives an updated statement of his ideas laid out in A Theory of Justice and other writings. Though I am far from an expert in political philosophy, it seems to me that Rawls does liberal political theory about as well it can be done. Robert Nozick’s praise of Theory in Anarchy, State and Utopia seems fitting for this work as well:
“It is a fountain of illuminating ideas, integrated together into a lovely whole. Political philosophers now must either work within Rawls’ theory or explain why not…. Even those who remain unconvinced after wrestling with Rawls’ systematic vision will learn much from closely studying it. I do not speak only of the Millian sharpening of one’s views in combating (what one takes to be) error. It is impossible to read Rawls’ book without incorporating much, perhaps transmuted, into one’s own deepened view. And it is impossible to finish his book without a new and inspiring vision of what a moral theory may attempt to do and unite; of how beautiful a whole theory can be” (183).
The major weakness of Rawls’ theory (to me) is that it presupposes a liberal constitutional democracy, and builds a theory from there. But this raises the question of how it really speaks to the human experience outside of liberal democracies.