Towards increasing regime complexity? Why member states drive overlaps between international organisations

Abstract

Multilateral cooperation in international organisations is characterised by regime complexity. The literature usually adopts a policy-focused perspective studying the properties, effects, and dynamics within given regime complexes for different policy areas. Yet few accounts of why states drive regime complexity have been provided in the literature. Therefore, we adopt a state-focused perspective and observe how states differ in the extent to which they foster complexity through overlapping memberships and policy competencies in international organisations. In order to explain this variation, we extract state motivations from the regime complexity literature, but also incorporate the role of geopolitical opportunity structures for complexity as well as interactions between both elements. The empirical analysis reveals that the power to pursue self-interests leads to duplicated policy competencies, whereas duplicating international organisation memberships by creating new international organisations or joining existing ones is costly and a less favoured route towards pursuing substantive gains. The motivation to gain external reputation also positively influences the overlap in membership and policy competencies. Moreover, the number of neighbouring states and the disappearance of deep-rooted ideological cleavages are important opportunity structures for states furthering complexity. Opportunity structures also reinforce the positive effect of power to pursue self-interests and external reputation motivations on complexity. Thus, we contribute to regime complexity research in showing that not all states equally foster regime complexity and this relationship is dependent on a specific context.