Kristina Mani's book has two broad goals, one modest and another much more ambitious. The first is to provide a fresh perspective on security cooperation between Argentina and Chile in their postauthoritarian eras. The second is to compel a reconceptualization of rivalries more generally in Latin America by explicitly connecting domestic and foreign policies. The analysis is buttressed by 68 in-depth interviews in the two countries, many with influential players, both civilian and military, in addition to primary sources.

Mani employs two main variables: regime cost (high/low) and veto players (empowered/weakened). Regime cost refers to “policies of the prior regime perceived within society to have been harmful to national, group and individual interests” (pp. 23–24). This relates in particular to the level of repression and human rights abuse committed by the regime. When regime costs are high, postauthoritarian governments are more likely to pursue an internationalist strategy as a way to reduce international conflict and thereby strengthen the democratic regime. Veto players refer to political actors who can block the changes—either publicly or behind the scenes–required to end rivalry. Most often, these are political parties and/or factions within the military that consider internationalism to be an affront to sovereignty and nationalism.

Combined, these two variables yield four possible outcomes: an impulsive internationalist strategy, a deliberate internationalist strategy, an impulsive statist-nationalist strategy, and a deliberate statist-nationalist strategy. The author places both Argentina and Chile as “impulsive internationalist” until 1995, at which point veto players have been weakened to the point that there was a more deliberate internationalism. The initial success of internationalism had convinced even many hardliners that greater cooperation was mutually beneficial.

A lesson from this success, Mani argues, is that civilian policymakers engaged the military by mobilizing receptive sectors of the armed forces, making defense as technocratic as possible, and embedding the armed forces in a network of civilians and officers who supported internationalism. These served to make the rivalry more of a professional than a political challenge. In that sense, she offers not only an analytical model but also a blueprint for policymakers navigating the process of democratization.

Mani's tracing of the intricate process of confidence building is excellent. Given how harmonious relations are now, it is perhaps too easy to forget that 35 years ago, Argentina and Chile came very close to war, after decades of distrust and disagreement over South Atlantic boundaries. Armed conflict was averted only after international mediation, most notably from the Vatican. After the end of military rule, civilian leaders saw international military cooperation as an integral component of an overall strategy of democratizing civil–military relations. Democratically elected presidents therefore pushed hard to make internationalism a reality. The author carefully traces the decision-making process in each country, as newly elected leaders dealt simultaneously with potential international conflict and domestic resistance.

Policymakers had to seek out sectors of the military that were sympathetic to the internationalist view. They carefully cultivated these allies and crafted a strategic outlook that combined civilians and officers from both countries. These interchanges fostered sustained, formal, civilian–military contacts that themselves contributed to improving civil–military relations. This insight should be considered an important part of Mani's contribution. Most often, the scholarly literature has viewed internationalist impulses mostly as a way to provide a post–Cold War mission for the military that did not involve internal security. Analyses of democratization may examine international influence on political transitions, but do not integrate foreign policy into the equation.

Once we start moving away from the book's case studies, however, theoretical application gets trickier. Mani defines a rivalry as “a fundamental disagreement over the resolution of issues between them for an extended period of time, and leads them to commit substantial resources toward challenging each other diplomatically or militarily” (p. 15). This pertains to a number of other cases in Latin America, but applies unevenly.

For example, Mani very briefly contrasts the Chile–Argentina success with the continued controversies that Chile has with Bolivia and Peru. In Bolivia and Peru, we might reasonably argue that there are empowered veto players (a high level of nationalism) and low regime costs (the authoritarian era is far in the past), yet both governments are increasingly resorting to the International Court of Justice (ICJ) for disputes with Chile, which implies “impulsive internationalism,” rather than an “impulsive statist-nationalist” strategy. What this might suggest is that the “regime cost” variable may not be as relevant as time goes on. The Bolivian military left power in 1982, and although the era of dictatorship was traumatic, by now there is no real fear of regression. However, Mani's model argues that low regime costs should correlate with a statist-nationalist response.

To be fair, the author views Peru's decision to take the case to the ICJ as an obstacle to confidence building because it signifies a failure of bilateral diplomacy (p. 219). In other words, states resort to outside actors only when they are incapable of advancing or unwilling to advance the security agenda with direct negotiation. Precisely how much that represents an impediment is a matter of interpretation, but at the very least it is a far cry from the more aggressive actions evident in the militarized Ecuador–Peru border dispute.

Nonetheless, we do see low-regime costs combine with internationalist strategies in recently resolved disputes between Uruguay–Argentina, Brazil–Paraguay, and Bolivia–Paraguay. Unlike Ecuador–Peru, resolution did not require intensive and extensive external support. In those cases, we do see ideological affinity between the presidents who finalized negotiated settlements, which Mani does not address. In all of those countries except Paraguay, we also see a process—even if imperfect—of democratized civil–military relations.

The aforementioned concerns are a testament to the thought-provoking nature of Democratization and Military Transformation in Argentina and Chile. Mani's goal of offering a novel approach to interstate rivalry is ambitious, and therefore almost by definition it invites quibbling. The logical next step for testing the generalizability of her model would be to identify all of the regional rivalries and how/whether specific disputes were resolved. At least to my mind, a key question to consider is temporal. Do the dynamics of confidence building change once the previous experience with dictatorship is a generation or more in the past? Another question relates to transitions. The four countries examined all moved from authoritarian to civilian rule, but can this framework apply to countries outside that context? We could then bring in other examples, such as Colombia–Venezuela and Colombia–Ecuador.

Notwithstanding such quibbles, the book will be of interest to those studying both rivalry and democratization as well as those who study Argentina and Chile specifically. The interplay between domestic and international factors deserves more attention, and Mani offers a useful framework for future research. With luck, there will be a paperback edition.