When are international organizations (IOs) effective in promoting interstate cooperation? What conditions and factors hinder their effectiveness? What make states break their commitments or skirt their obligations following adjudication by international courts (ICs)? These are the questions that Lauren J. Peritz seeks to answer in this book. Its focus is on a specific kind of IO, international economic courts, and the case studies are the World Trade Organization’s Dispute Settlement Mechanism (WTO DSM) and the Court of Justice of the European Union (ECJ).

Domestic political constraints, Peritz finds, are the major drivers of the variations seen in state compliance with international courts’ (ICs) rulings. A high number of domestic veto players make states less responsive to adverse international rulings, thereby hindering ICs’ effectiveness. When institutional legislative constraints and domestic interest groups converge, they pressure governments to resist unfavorable WTO rulings, for instance (pp. 114–32). In fact, states face domestic incentives to “cheat” in response to pressures from domestic interest groups. States evade enforcement by the courts, and domestic constraints lock in the violations of international trade policies and commitments. Going even further with veto players theory, the book argues that “the effectiveness of international courts is a function of the domestic politics of litigant governments” (p. 8). A cross-national variation of the outcomes is determined by various forms of gridlock and opportunism.

Despite these domestic hindrances, however, Peritz finds that ultimately international economic courts are indeed effective in restoring international cooperation under certain conditions. For instance, the WTO DSM and the ECJ have advanced international cooperation in concrete ways, making states adjust their policies and abide by their rulings. In that sense then, international adjudication furthers international economic cooperation.

Delivering on Promises makes two major contributions to the study of international cooperation. First, it advances the literature on the effects of domestic politics on international cooperation, articulating the mechanisms through which veto players undercut their governments’ willingness or ability to abide by adverse international rulings. As such, these veto players do indeed curtail the ability of IOs to effectively facilitate cooperation. Second, these findings open avenues to improve the effectiveness of international organizations through institutional design. IOs can better mitigate the constraints to compliance by introducing more flexibility mechanisms—allowing, for instance, states to temporarily defect from or delay compliance.

A rational choice approach guides Delivering on Promises’ theoretical framework, taking states as strategically motivated actors that try to maximize short- and long-term gains. Empirically, the author uses large-N data for statistical analyses, complemented by the two case studies. In chapter 2, the author presents the theory and shows how veto players—division of authority within the state—can hinder compliance with ICs. The four hypotheses to be tested empirically are also presented. Chapter 3 introduces the WTO and EU courts and how governments use them to advance their interests. The author then tests the hypotheses, showing that states are less likely to comply with WTO rulings when domestic politics and veto players’ interests interject (chap. 4). One of the strengths of the analysis is the construction of a novel dataset on (non)compliance with adverse WTO rulings and drawing out the link between such (non)compliance with the extent of domestic constraints, whether bicameralism, federalism, or partisan divisions (pp. 120–32). The author finds that veto players do undermine the ability of the WTO to enhance economic cooperation and trade between disputing governments (chap. 5). Chapter 6 focuses on the ECJ and shows that defendant states with more internal divisions, whether institutionally or politically, experience fewer cooperative outcomes in trade. The book’s concluding chapter offers avenues for ICs to mitigate these constraints and become even more effective in facilitating international cooperation.

The book’s excellent analysis is a major step toward better understanding international cooperation and the domestic levers that hinder it. A major takeaway is that, despite their constraints, IOs are quite effective in facilitating interstate cooperation. However, given the book’s focus on international economic courts and the effects and afterlives of adjudication of trade and economic disputes, some caution may be warranted about transposing these results to other international regimes such as human rights or international criminal justice; there are qualitative differences between these regimes and what they mean for IOs and cooperation in general.

Rational choice approaches also have their limitations, because states may indeed be motivated by factors beyond cost-benefit analyses and material gains. Viewing states as signing treaties and subscribing to international regimes primarily because they advance their material interests (p. 25) limits our understanding of what other factors may motivate states. This is where a constructivist approach can provide more insights on why states join international regimes, ratify treaties, and abide by their commitments (or not).

A recurring issue in the scholarship about IOs, and international courts specifically, is how best to distinguish compliance from cooperation. Peritz makes this distinction by considering compliance as states “devis[ing] policies that are consistent with the letter of the law” (p. 33). Cooperation, in contrast, is framed around “cooperative outcomes,” which refer to whether states actions skirt “their substantive obligations” (pp. 32–35). Thus, the author follows the scholarship that distinguishes first-order compliance—states abiding by the provisions of a treaty—and second-order compliance, when states adjust their policies after a finding that they had violated the rules (pp. 36–37). Cooperation then (or cooperative outcomes) denotes more trade between states, which can be measured as “product-level trade flows” between disputing states (p. 177).

There is, however, another way of defining compliance and cooperation and disentangling the two in international regimes. In human rights and international criminal justice for instance, compliance can mean a state abiding by a treaty that it has ratified, by a binding court ruling, or by an agreement. For treaty-based courts such as the ICC, executing a warrant for the arrest of a suspect is a matter of compliance for states that are parties to the Rome Statute. For those states that are not members of the court and so are not bound by that warrant, executing it or not would simply be a matter of cooperation with the court. If we transpose that frame to the WTO or ECJ, we may say that a state that is party to the dispute is bound to comply, whereas another state may adjust its policy after a decision that they were not bound to, which would be considered cooperation.

Overall, Peritz has written an excellent book that is theoretically cogent and empirically rich. It advances our understanding of the domestic politics of international cooperation and the effectiveness of international courts.