Brian Rathbun's book is an important contribution at the interface of international relations and comparative politics, providing a fascinating, well-researched analysis of the impact of domestic politics on the formulation of foreign and defense policy in three major European states: Great Britain, Germany, and France. Rathbun makes two key claims: Parties articulate and implement different policies in the area of peace enforcement and European defense cooperation due to their different ideologies. Second, contrary to the view that parties formulate policies to win elections, he argues that, in general, parties win elections to formulate policies. In an empirically rich account of the effects of partisan politics, Rathbun analyses the views of—and disagreements among—the main parties in the UK, France, and Germany regarding peace enforcement in Bosnia and Kosovo, and regarding the establishment of an European Union capacity for carrying out peace enforcement operations.

Rathbun argues that in contrast to parties on the right of the political spectrum, leftist parties believe less in the use of force, particularly for strategic purposes; have a more inclusive definition of national interest; and are more willing to rely on multilateral cooperation in pursuit of their goals. He notes that peace enforcement generates values conflicts, especially for leftist parties that are forced to choose between the peaceful resolution of conflicts and the protection of basic human rights abroad. When faced with such conflicts, he seeks to demonstrate, politicians support different policies depending on their positions on the ideological spectrum and their country's historical legacies in the area of armed conflict.

Partisan Interventions successfully challenges the argument, which for many years was seen as conventional wisdom in the field of international relations, that the national interest is an objective datum, unaffected by domestic politics. Moreover, Rathbun demonstrates the weakness of the argument that politicians are no more than instrumental vote seekers. Indeed, contrary to the argument that parties are primarily guided by electoral considerations, his empirical cases clearly demonstrate that in the important area of peace enforcement, parties were largely motivated by principles. His book is important from yet another point of view: It captures the dynamic nature of foreign policy, showing that foreign policy positions change not just as a result of government turnover, but also as a result of learning within a given party. Particularly instructive in this sense is the author's analysis of the way in which the Bosnian experience led to a reassessment of positions on the question of peace enforcement, especially for leftist parties, leading them to question antimilitarism and to become stronger supporters of humanitarian intervention.

While Rathbun is extremely persuasive in showing the limits of the approach that regards parties as no more than office seekers, his critique of cultural theories is a little less convincing. Indeed, in several instances, he seems to underestimate the explanatory power of the argument—put forward by scholars within the “culturalist” camp—that prevailing definitions of national identity generate unique national approaches to international relations.

To take a concrete example, let us briefly examine the British Labour Party's position on European defense. Rathbun takes issue with the culturalist claim that a sense of national identity that is incompatible with federalist visions of European political order explains why British governments, be they Labour or Conservative, have opposed a deepening of European integration (p. 154). His argument is that due to its ideology, Labour was not inhibited by concerns that “adding a competency in security to the EU” would contribute to the union's evolution into an “organization that threatens national decision-making autonomy” (p. 155). Rathbun is right that the Labour Party is, in general, more supportive of the idea of enhancing the EU's security role than the Tories, and that Tony Blair's government played a key role in establishing the structures for EU intergovernmental cooperation in crisis management. In that respect, the shift from a Tory to a Labour government in Britain had significant foreign policy implications. At the same time, however, the transformation in the British approach to the EU should not be overstated. In fact, consistent with a definition of national identity that is incompatible with a supranational vision of Europe, the British Labour government has been keen to stress that the EU it supports is a union of sovereign states. For example, during recent negotiations for an EU Constitutional Treaty, the British government insisted on the need to safeguard unanimity—versus qualified majority voting—on issues such as defense and foreign policy. Linked to its concern to preserve national veto power in the key areas of defense and foreign policy, the British Labour government objected to any measures seen as a threat to NATO, traditionally regarded by Britain as the foundation of collective security in the Euro-Atlantic area.

In a broader perspective, it is also worth noting that some aspects of the book are a little undertheorized. For example, Rathbun argues in Chapter 1 that he seeks to address a limitation in the existing constructivist literature in international relations, that is, the relative neglect of the domestic level of analysis. His claim is that international norms are more likely to take root when they land on fertile ground; in his words, political parties “become the domestic vehicles of international norms” (p. 7). The attention to domestic politics is very important, but the rich empirical account provided in the book actually tells a dialectical story, linking domestic and international levels in multiple ways. Unfortunately, this dialectical relationship is not fully analyzed by the author.

Particularly relevant are the cases in which, in addition to acting as domestic vehicles of international norms, parties, and sometimes particular individuals within parties, played important roles in the promotion of particular international norms. Consider, for example, the evolution of leftist thinking in France on the question of humanitarian intervention. Rathbun argues that in the 1990s, France's “Second Left” was “primarily responsible for defining humanitarian intervention as an issue for the left, not only in France but internationally” (p. 131). This empirical material is extremely interesting, and the account would have been even stronger if he had taken this opportunity to provide a deeper analysis of the types of processes and techniques through which a particular problem, such as humanitarian intervention, was articulated—and accepted by the relevant parties—as an “issue for the left.” Linked to this, the book would have been even richer if Rathbun had explored the extent and way in which the evolution of thinking among leftist parties on the issue of humanitarian intervention had a broader impact on domestic and international debates that occurred in the 1990s regarding the nature and desirable limits of state sovereignty in the post–Cold War period.