 There have been many mutual influences between normative economics and political philosophy. In particular, Rawls’ difference principle (Rawls 1971) has been instrumental in making economic analysis of redistributive policies pay some attention to the maximin criterion, which puts absolute priority on the worst-off, and not only to sum-utilitarianism. (It has taken more time for economists to realize that Rawls’ difference principle applies to primary goods, not utilities.) Conversely, many concepts used by political philosophers come from various branches of normative economics (see below).