Navigating Regime Complexes in Turbulent Times—The EU’s Interaction with Other International Organizations in Crises

Abstract Over the past decades, the European Union (EU) has confronted multiple crises, which have prompted swift political responses from the EU’s member states and institutions. While there is a broad literature about the EU’s internal responses to crises, we know much less about the EU’s interactions with external actors. Because the EU is part of issue-specific regime complexes, it has cultivated relationships with international organizations (IOs) across a multitude of issues. We argue that during crises, the EU has heightened incentives to complement its internal crisis response by interactions with other IOs that vary in their qualities. How can the EU’s external engagement during crises be conceptualized and theoretically explained? Drawing on the regime complexity literature, we identify three different types of interactions among IOs to conceptualize the EU’s varying external engagements during crises periods: pooling, division of labor , and competition . We further argue that under the condition of regime complexity, the choice of interorganizational interaction is shaped by the convergence of means and ends among the respective dyads of IOs. To illustrate the usefulness of our typology for the study of the EU’s external responses to crises, as well as the plausibility of our argument, we analyze three instances of EU–IO relationships in crisis contexts: pooling between the EU and the International Monetary Fund (IMF) to address the sovereign debt crisis, division of labor between the EU and the North Atlantic Treaty Organization (NATO) in response to Russia’s war of aggression against Ukraine, and competition between the EU and the European Court of Human Rights (ECtHR) during the “migration crisis.”