How does the World Trade Organization (WTO) affect the internal policies of one of its key members, the European Union (EU)? That is the central question of Alasdair Young’s Supplying Compliance with Trade Rules. The issue of compliance with WTO rules has recently received growing attention from scholars of international organizations and trade policy, but Young has been one of the pioneers of this field. He has been writing about the topic for two decades. His contributions have always provided a nuanced correction to, on the one hand, realist scholars who argue that the WTO has no constraining effect on its (powerful) members and, on the other hand, WTO critics who claim that its rules limit governments’ policy space to an unacceptable extent. Young’s earlier work has demonstrated that while member states comply more with WTO rules than realists would expect, they cannot be forced to change their policies when this would go against fundamental domestic interests or values.

In Supplying Compliance Young collects the thinking and work he has done on the subject over the span of two decades and translates it into a coherent whole. As it has been established by now that the compliance rate with WTO rules (first-order compliance) and rulings (second-order compliance) is decent, while allowing for “efficient breaches,” the book’s key aim is to explain why states choose to comply. Again, Young aims to challenge the conventional wisdom on this question. International political economy scholars of compliance have put forward an account that identifies exporters concerned with retaliation against their foreign sales in case of rule violation as the main agents of compliance. When a government adopts a policy that has been found to violate WTO rules, exporters in the country will lobby their government to change the policy and bring it in line with WTO prescriptions because otherwise they might be targeted by WTO-sanctioned retaliatory tariffs by the complainant party. This explanation is as elegant as it is unrealistic. It assumes that exporters follow WTO disputes on issues unrelated to their business and will decide to invest in lobbying against the uncertain risk of retaliatory tariffs, which are only seldomly imposed and often only years after a ruling on a dispute has been made.

If it is implausible that compliance is the product of the WTO’s craftily designed sanctioning mechanism that makes exporters agents of compliance, why do states follow WTO rules then? An institutional explanation, often integrated into demand-oriented accounts, is that decision-making procedures determine if compliance is successful. If the threshold to change a WTO-incompatible policy is high—if there are many veto actors—the probability of compliance will be lower. While the literature has so far focused on the demand for compliance (by exporters) and the decision-making rules that make compliance more or less likely, Young proposes a rationalist supply-side explanation. This account sees policy makers being intrinsically motivated to comply with WTO rules rather than responding mechanically to societal demands. Policy makers who care about the effectiveness of the WTO are interested in complying with WTO rules because they want to avoid encouraging reciprocal abrogation—noncompliance by others—and want to keep a good reputation within the organization. These motivations to comply will vary among policy makers, with those responsible for trade policy more concerned than policy makers whose mandate is protecting public health or the environment, and who will be less willing to compromise on these policies if these are found to contravene WTO rules.

Young tests the relevance of exporter lobbying, veto players, and preferences of policy makers for explaining WTO compliance in the EU through a mixed-methods approach combining a qualitative comparative analysis (QCA) of all 23 EU policies that have been found to violate WTO rules or commitments and five case studies in which the EU’s response to a lost dispute is process traced. In the QCA analysis, lobbying by exporters is operationalized as the share of EU exports going to the complainant party or parties, veto players as the decision rule for changing policies (involvement of and voting thresholds in the Council and/or European Parliament), and preferences of policy makers as the policy domain from which a policy stems (trade or not). The QCA analysis shows that the economic importance of the complainant and the number of veto players inside the EU do not matter, and even leads to the counterintuitive finding that in all instances in which the EU was confronted with a powerful complainant, it did not change its policies. Trade policy appears to be a sufficient condition for compliance: Every time a trade policy measure was successfully challenged before the WTO, the EU changed its policies in a swift way.

The QCA analysis leads to a selection of cases to study more in depth that vary in all three conditions and the outcome: beef, bananas, genetically modified crops, sugar, and bed linen. These detailed case studies confirm the finding from the QCA analysis that exporters have been almost completely absent in processes of policy change in the EU in response to an adverse WTO ruling. They also show that EU trade officials are strongly committed to WTO rules and have been willing to enact swift changes in all successfully challenged policies that fall under their responsibility. Nontrade officials, however, do not change their preferences in response to an adverse WTO ruling. When trade policy officials cannot twist their colleagues’ arms, the EU might not comply with a WTO ruling. The book convincingly shows that the EU often, but not always, complies with WTO rulings and that this is mainly the result of efforts by trade officials who are intrinsically concerned about the legitimacy of the multilateral organization and the EU’s reputation in it. The mixed-method analysis combines rigor and parsimony with empirical richness and is written with characteristic precision and lucidity. The book adds to our insights into the causal mechanisms leading to compliance with the WTO, and international organizations in general. It corrects alternative explanations for compliance centered on exporter lobbying or the EU’s normative exceptionality.

However, the book’s findings provoke some questions that are not completely accounted for. First, if trade officials are so concerned about WTO compliance and trade policy measures are always swiftly brought in line with adverse rulings, why do WTO-incompatible trade policies come into existence in the first place? Is this simply the consequence of (vague) WTO rules being misinterpreted by these officials? Do trade officials’ preferences change after a ruling, as the book argues, or are there perhaps different preferences even among (different branches of) trade policy makers, and does a WTO ruling strengthen some over others? Were trade policy makers somehow forced to adopt a policy against their preferences in the first round, and did they eagerly seize on a WTO ruling to bring the policy in line with their actual preferences? What happens within the group of trade policy makers that explains how they move from first-order noncompliance to swift second-order compliance could have been explored more in the book. Second, how to explain the counterintuitive finding that, in each of the cases in which the EU did not change its policies in response to an adverse WTO ruling, it was confronted with a powerful complainant? Here, the book could have profited from integrating insights on not only determinants of compliance with WTO rulings but also determinants of initiations of WTO disputes. Perhaps powerful WTO member states, the United States in particular, use the WTO to raise fundamental disagreements with the EU (e.g., on risk assessment), to which the EU is unlikely to respond. While weaker WTO member states might only challenge EU policies when they think it is very likely that they will win the dispute and that the EU will subsequently change its policies. In other words, variation in compliance is not only determined by how compliance is supplied within the defendant but also how the decision to launch a dispute is made within the complainant.