Does Institutional Proliferation Undermine Cooperation? Theory and Evidence from Climate Change

Global politics has undergone a tremendous institutional proliferation, yet many questions remain about why states join these new institutions and whether they support cooperation. I build on existing work to develop a general theory of state participation in dense institutional environments that also helps to explain cooperative outcomes. I argue that states may be dissatisfied when cooperation proceeds either too slowly or too quickly and that these two types of dissatisfaction motivate opposing participation behaviors. Deepeners are states that are dissatisfied with the slow pace of cooperation and join institutions to support cooperation, while fragmenters are states dissatisfied with the quick pace and join institutions to undermine cooperation. I evaluate my argument using new data on sixty-three climate institutions and states' greenhouse gas mitigation targets in the Paris Agreement on Climate Change. I find that membership in climate institutions designed to facilitate implementation is associated with more ambitious targets, while membership in general is unrelated to targets.