Unequal inequality aversion within and among countries and generations

Suppose that, for whatever reason, it is decided that inequalities within countries are more offensive than inequalities between countries, and that inequalities between populations living together are more offensive than inequalities between generations living in different times. Can a social welfare function express that preference? We show that it is actually difficult to incorporate such a localist preference into a social welfare function, except in a limited way (i.e., from a situation of specific similarity between countries). We also show that in order to obtain such preferences, the relative size of inequality aversion within and between countries may be counter-intuitive in some relevant cases, in the sense that a greater inequality aversion may happen to be required across countries than within countries. This research highlights new social welfare functions that aggregate the outcomes of evaluations over pairs of agents.