International Organization

Research Article

A Strategic Theory of Regime Integration and Separation

Tana Johnsona1 and Johannes Urpelainena2

a1 Duke University, Durham, N.C. E-mail:

a2 Columbia University, New York. E-mail:


States frequently disagree on the importance of cooperation in different issue areas. Under these conditions, when do states prefer to integrate regimes instead of keeping them separated? We develop a strategic theory of regime integration and separation. The theory highlights the nature of spillovers between issues. Positive spillovers exist when cooperation in one issue area aids the pursuit of objectives in another issue area; negative spillovers exist when cooperation in one issue area impedes this pursuit in another issue area. Conventional wisdom suggests that both positive and negative spillovers foster greater integration. We argue that negative spillovers encourage integration while positive spillovers do not. States integrate not to exploit positive spillovers between issues but to mitigate negative spillovers. To test our theory, we examine the degree of integration or separation among environmental regimes.

Tana Johnson is Assistant Professor of Public Policy and Political Science at Duke University, Durham, N.C. E-mail:

Johannes Urpelainen is Assistant Professor of Political Science at Columbia University, New York. E-mail:


  We thank two anonymous reviewers, the editors of International Organization, Robert O. Keohane, Justin Leinaweaver, Ronald Mitchell, Autumn Lockwood Payton, and seminar audiences at Princeton University and the 2011 annual convention of the Midwest Political Science Association for comments and advice. Tana Johnson thanks the Niehaus Center for Globalization and Governance at Princeton University for generous support. Supplementary material can be found at