Constitutions are more than their text; a constitution is also a set of conventions, or expectations that constituents have about one another's behavior. That is, constitutions have a culture. The coherence between the constitutional law and constitutional culture determine a constitution's success. Constitutional culture and constitutional law co-evolve; by understanding the influence of multiple institutions, one may make predictions about the likelihood of the emergence of a prosocial constitutional culture. There are reasons to believe that federalism might encourage the development of a prosocial constitutional culture, but the effect is far from certain.This essay concludes with questions to consider in while assessing Afghanistan's prospects for constitutional success.