Here’s an interesting quote from Rawls:
A conception of Justice cannot be deduced from self-evident premises or conditions on principles; instead, its justification is a matter of the mutual support of many considerations, of everything fitting together into one coherent view.
~A Theory of Justice, §4
This reflective equilibrium is a tacit rejection of foundationalism in the field of political science, and it seems to me that Rawls’ view is, in this respect, at odds with Natural Law jurisprudence and political theory. It is interesting to note nevertheless, since it fits nicely in with other philosophical views in vogue in Rawls’ time (from Lawrence Bonjour’s coherentist epistemology to W.V.O. Quine’s dispensability thesis). However, once coherentism passes out of fashion, it seems like Rawls may have to lose popular appeal as well.