摘要 : In many issue areas in international political economy (IPE), interstate cooperation is governed by a dense network of distinct but overlapping international institutions. Whether this environment of 'regime complexity' strengthen... 展开 In many issue areas in international political economy (IPE), interstate cooperation is governed by a dense network of distinct but overlapping international institutions. Whether this environment of 'regime complexity' strengthens or undermines cooperation is a subject of intense debate. Some argue that overlapping institutions enhance legitimacy and flexibility, while others claim that opportunistic forum shopping enables states to escape compliance with rigorous rules. This article reconciles this debate, demonstrating that regime complexity has contrasting effects depending on the degree of value differentiation among institutions. In issue areas where undifferentiated institutions function as substitutes, forum shopping will reduce the regime's ability to discipline state behavior. However, in issue areas where institutions are differentiated by value - i.e. the benefits they provide increase as rules become more rigorous - institutional overlap can increase policy change among states. I demonstrate these dynamics formally and provide empirical evidence in a comparative analysis of the regime complexes for election observation and forest-related carbon offsets. 收起