Why have Argentina and Chile ended their historical rivalry and pursued cooperation on security issues in the last few decades? What tools did policy-makers use to transform the military's views and behaviour? Kristina Mani's book addresses these questions and highlights the implications of her research for relevant concerns in the fields of international relations and comparative politics: the interaction between democratisation processes and security cooperation and, more broadly, the interplay of domestic and international factors in the shaping of foreign policy and domestic politics.

The book makes a number of timely contributions. First, it calls attention to relatively less-researched cases. Latin America in general and the Southern Cone in particular have not been priority areas for US-based scholars in international relations and foreign policy. Second, it offers an innovative approach that challenges the traditional view of foreign policy and security issues as dominated by realist considerations and systemic dynamics driven by great power's actions. Third, it questions existing assumptions about the connection between democratisation and hostile (that is, conflict-/war-prone) foreign policies and when and how enduring rivalries start and end. Fourth, it identifies some policy instruments that proved effective in dealing with the military problem in the Southern Cone and fostering security cooperation.

The main argument points to a significant learning process among political and military elites that cemented their views of the benefits of cooperation. Mani relies on rigorous field research (mostly interviews and archival work) to trace the decision-making and policy implementation processes that led to that outcome. The core of the book provides a background overview of the origin and evolution of rivalry between Argentina and Chile, an analysis of contextual variables and major developments that facilitated security cooperation in the 1990s, and a detailed explanation of how international confidence was built up and the military's perceptions transformed. In the final chapters the author compares her findings to the rivalry between Ecuador and Peru, in which the opposite outcome can be observed in the same decade – that is, military conflict and persistent obstacles to security cooperation. She also aims at extending her conclusions to other cases in the region, assessing the evolution of cooperation in the 2000s and identifying some lessons regarding civil–military relations in democratising states.

Mani draws on several insights from international relations and comparative politics to propose a complex explanation of why and how Argentina and Chile ended a long rivalry. On the one hand, she argues that the high political, economic and social costs imposed by authoritarian regimes on societies made elites realise the benefits of resolving disputes and pursuing security cooperation, which would indirectly reinforce their attempts to implement a neoliberal, pro-integration economic policy and to consolidate the fragile democratisation process. In other words, Mani claims that this case of security cooperation has to be understood in the context of the construction of a grand ‘internationalist’ strategy that articulates new domestic and regional coalitions of public and private actors, in contrast to the ‘statist-nationalist’ strategy that emerges when policy-makers pursue military competition and an economic model that gives priority to national security goals. On the other hand, the author borrows the concept of veto players to explain how democratic leaders managed to neutralise the military, transforming it from an opponent to a stakeholder in internationalism and, indirectly, gaining its subordination to civilian authority. She identifies three concrete mechanisms used to achieve this outcome: mobilising some sectors of the military to participate in confidence-building measures such as joint exercises or international peacekeeping missions; technocratising and professionalising the management of military affairs so as to minimise politicisation; and embedding the military in a broader network of actors that helped socialise it into internationalist ideas.

The book succeeds in providing an interesting answer to the initial research questions. More importantly, it triggers the reader's curiosity to learn more about the topic, explore the implications and pose more questions. For instance, although bilateral cooperation has persisted in the 2000s, the convergence of mutually reinforcing strategies in the economic and security realms is not at work any longer since at least one of the partners (Argentina) has moved towards state interventionism and protectionism in its economic policy, economic integration has stalled, and new domestic and regional coalitions have emerged around a post-neoliberal discourse. Sources of instability have also changed in the region, confronting unfinished processes of democratisation with new dilemmas, as we observe in the several politico-institutional crises (mostly led by massive social mobilisation or interest groups rather than the military) that abruptly ended presidential mandates in Latin America, including Argentina. If grand strategies and coalitions undergo deep changes in just a decade, can these factors constitute a solid base to explain, compare and perhaps predict the evolution of enduring rivalries? The author briefly acknowledges a shift in the economic orientation (p. 217), but she does not elaborate the analytical implications of all these changes for her model.

Also, the book does not engage with broader debates on the evolution of the security agenda in South America, an area that has gone through remarkable transformations since democratisation. Besides concerns with how to manage civil–military relations, democratisers have attempted to shape the securitisation of both domestic and transnational issues (especially after 9/11), re-create forms of governance vis-à-vis new threats and the changing position of key actors in these matters (namely Brazil and the United States), and attain policy consensus and coordination that goes well beyond bilateral relationships. Mani's rethinking of rivalry does not delve into the growing literature that addresses these developments, but hers is a thoughtful study and a must-read for specialists, scholars and practitioners alike.