THE POLITICS OF SCOPE - ENDOGENOUS ACTORS, HETEROGENEITY AND INSTITUTIONS

The international relations (IR) and common-pool resource (CPR) literatures disagree on the impact of incresing numbers of actors on collective action. They also disagree on the impact of actor heterogeneity. These differences can be understood in terms of the endogeneity of institutions, exemplified here by membership rules. The number and variety of actors need not be an exogenous aspect of a collective-action problem but rather may be determined as part of the institutional rules. Successful CPRs regulate their membership either through exclusion or by enforcing contributions. In some cases this is supported by nesting in external institutions, in other cases enforcement is decentralized and in yet other cases collective action is achieved through locally centralized arrangements. This latter category suggests a much richer range of possible institutional solutions than is found in standard IR conceptions of anarchy or hierarchy. In terms of the various types of actor heterogeneity discussed in the paper, it suggests a need for better understanding of the role of 'community' in supporting collective action at both the local and international levels.