One often hears that integration in Europe magnifies the political voice of European countries on the international scene. The larger size of the European Union market surely makes investment in any particular European country more attractive, and importers are certainly more eager to satisfy a regulatory requirement if doing so will give them access to the entire European market. But does unity bring negotiating clout, too? This is the question Sophie Meunier investigates in her book Trading Voices.

Cutting against the expectation of rising political clout are the complaints of political negotiators who note that Europe often sends to negotiations national and European-level diplomats who disagree with each other. Indeed, it often is not clear where the buck stops—or as Henry Kissinger put it: “If I want to talk to Europe who do I call?” The reason is that the European Union has a shared executive branch (the Commission and the Council), two legislative branches (the Council and the Parliament), and two civil bureaucracies (Committee of Permanent Representation [COREPER] and the Commission). The authority of each institution can vary by issue; thus, the Commission can have authority to negotiate on behalf of European states for certain issues, yet member states retain the authority to bargain on their own in other issues. Sometimes the voting rule to adopt an agreement is unanimity, which magnifies the voice of obstinate states, and other times the voting rule is qualified majority. Sometimes the European Parliament needs to be involved in the making of political agreements, and other times it does not. And if any European actor thinks the Commission has botched procedure, overstepped its authority, or not selected the correct voting rule, the negotiated outcome can be challenged in front of the European Court of Justice. All of this can make negotiating with Europe frustrating—but does not per se undermine European clout.

Meunier's analysis takes this complex nature of European Union politics as a given. Building on Robert Putnam's insight that domestic political divisions can be both a liability and strength in international negotiations, Meunier charts where a common or divided voice creates bargaining leverage in political negotiations. Putnam showed us that internal divisions are a negotiating liability when the bargaining partner can pick off domestic actors, choosing to satisfy the domestic faction closest to the partner's ideal point. Internal divisions will create strength when the negotiator can force the bargaining partner to give concessions by credibly claiming that certain deals would not be sellable at home. Meunier operationalizes this insight by looking at the extent of autonomy delegated to the Commission negotiator (its negotiating competence) and the voting rules to adopt an agreement. Going beyond Putnam, she adds that it matters whether or not Europe is defending the status quo (in which case it can veto any deal that aims to change the status quo), compared to situations where Europe is trying to change the status quo (in which case negotiating partners can block agreements). The bottom line of the argument is that the ability of the Commission to claim that its hands are tied at home and the ability of bargaining partners to pick off the European factions closest to their position varies, depending on the extent of Commission negotiating competence, the voting rule to adopt negotiated agreements, and whether Europe aims to defend or change the status quo.

Where the EU is conserving existing policy and requires unanimity to adopt an agreement, integration brings strength because any one country can veto international policy change, and thus collectively, European countries maximize their bargaining leverage. Where the EU is trying to reform policy and the voting rule is unanimity, integration undermines the EU because negotiating partners can encourage the member state closest to their position to undermine the EU's negotiating position. These two situations are the most likely to lead to failed negotiations with the EU. Where the EU is trying to conserve existing policy and the voting rule is qualified majority voting, the collective negotiating power is lower than what it might be if the voting rules were unanimity. But the Commission will have more flexibility, and so the chance that negotiations will succeed is higher. Where the EU is trying to change existing policy, and the voting rule is qualified majority, negotiating partners will be unable to exploit divisions within Europe, and so integration is not a liability, and perhaps even a strength.

These arguments are illustrated through carefully selected cases that create variation in Commission negotiating competence and voting rule. The cases—the Kennedy Round agriculture negotiations, the Uruguay Round agricultural negotiations, negotiations over the Open Sky Agreement, and negotiations regarding public procurement rules—include both “offensive bargaining” where the EU is trying to change the status quo and “defensive bargaining” where the EU is trying to block efforts to change policy. Meunier gets some of the best leverage for her argument where the Commission's bargaining authority changes over time, allowing her to show that it was the bargaining authority, and the voting rule needed to support the Commission's agreement, that influences whether unity is providing political leverage in negotiations.

The best thing about this book is the clarity in writing, which itself reveals a clarity of thought. One wishes the EU were a less complex institution, so that the answer was a little more hummable. But the EU is what it is. Meunier provides an excellent guide for thinking through how political complexity complicates Putnam's simple two-level story. She also is mindful that the rules themselves reflect preferences of governmental actors who are cautious in delegating away negotiating authority. In this way, her argument carries beyond Europe, because it shows us that there really is a great variety of ways to delegate authority to negotiators, yet tie their hands at the same time, and these ways affect bargaining outcomes.

Overall, the study brings the best of social science tools to answer the question of how integration theoretically affects international negotiations. Such things as the skill of the negotiator, understandings shaping negotiating positions, domestic political factors underpinning national positions, and larger international political contextual factors are outside of the framework, but not forgotten in the case study discussions. Indeed, one appreciates that in the conversation of whether integration brings strength, Meunier never forgets that strength is not the only thing that matters. Strength is worth little if negotiations stalemate, to the detriment of all. Collective strength is also not the same as collective benefit—there are distributional consequences across actors.

Translating the book's insights into a negotiation manual for issues beyond Meunier's cases will take some work. Anyone who negotiates with the European Union must first—as she did—invest in understanding who in Europe answers the telephone for your issue. After one figures this out, her framework provides a ready way to think through the political consequences that will follow from the voting rules and the level of discretion granted to the Commission.