Institutional effects on state behavior: Convergence and divergence

We develop a new typology for examination of the effects of international i nstitutions on member states behavior. Some institutions lead to convergenc e of members' practices, whereas others result, often for unintended re aso ns, in divergence. We hypothesize that the observed effect of institutions depends on the level of externalities to slate behavior, the design of the institution, and variation in the organization and access of private intere sts that share the goals of the institution. We illustrate these propositio ns with examples drawn from international institutions for development assi stance, protection of the ozone layer, and completion of the European Union 's internal market. We find that significant externalities and appropriatel y designed institutions lead to convergence of state behaviour, whereas div ergence can result from the absence of these conditions and the presence of heterogeneity in domestic politics.