Commentary—Evolving Regionalism in Global Governance

ABSTRACT The isolationist turn in US foreign policy likely heralds a shift in how states engage with the longstanding institutions of global governance. We argue for the importance of a multilevel approach to understanding how domestic, national, and regional factors play into states' strategies in seeking partners and choosing international forums. We illustrate this approach with two cases: Europe and East Asia. Factors at all three levels appear to influence states' behaviors, with implications for different ranges of responses to US foreign policy across regions. The European Union acts as focal point for domestic institutions and a wide range of policies, while NATO members develop material capacity independent of the United States. East Asian states are far more diverse in their responses to US policy, with regional institutions somewhat limited in their capacity to handle non‐economic issues. These examples point to an evolving regionalism in international affairs.