Why fight? Engaging in violence is costly, so why do the combatants in territorial conflicts fail to reach an agreement? (See James D. Fearon, “Rationalist Explanations for War,” International Organization, 49 [1995]: 379–414.) One answer is that the stakes are indivisible—the two sides cannot agree to a split of the territory. There is something about the land or issue in question that makes it impossible to divide at all, so there is no room to bargain. The book under review seeks to explain where “indivisibility” comes from, as Stacie E. Goddard persuasively argues that it is not an inherent property in any hunk of land. This is an important move because it means not only that divisibility can vary over time in response to events and politics but also that indivisible territories can become divisible again.

Thus, the book's first necessary step and perhaps most significant contribution is demonstrating that indivisibility does indeed vary, and, in this, Goddard is most persuasive. As the subtitle conveys, her cases are two of the most well-known and studied protracted conflicts with significant international dynamics: Northern Ireland and Jerusalem. What I did not know before reading this book is that the supposedly indivisible lands were quite divisible long ago. Actors on all sides of the Ireland conflict in the mid-nineteenth century were willing to negotiate to divide sovereignty over the island. More strikingly, Jewish leaders actually preferred an international authority to govern the holy sites in Jerusalem until the 1967 war changed the dynamics. In her case studies, Goddard shows how these territories became increasingly viewed as indivisible, to the point where indivisibility became treated as a social fact. To truly demonstrate that divisibility varies, she must then show how an indivisible territory can lose that status and become divisible again. The recent events in Northern Ireland help her make that case.

Making divisibility a variable then requires an explanation of how and why it can vary. Goddard finds that existing efforts via rationalist and constructivist approaches fall short. She argues that rationalist approaches tend to assume away indivisibility, whereas constructivists tend, ironically, to be too fixed in their expectations. That is, those who focus on social construction may end up predicting too much conflict and not enough malleability in indivisibility as the agents tend to drop out of the analyses. Instead, she argues that how actors legitimate their claims alters the coalitions and politics surrounding the issue, often opening up room for compromise but sometimes also producing deadlock. In doing so, she bridges the rationalist–constructivist divide.

Goddard's second significant contribution is her social network approach, which combines network analysis with legitimation. Legitimate claims do not exist in a vacuum but are tied to key individuals who are—by happenstance or by hard work, charisma, and strategy—positioned in networks of individuals, groups, and organizations. Not every claim resonates and is seen as legitimate, and different people with the same claim will have varying degrees of success, depending upon how they are positioned in the various networks. Some claims can alter the structure of networks by breaking alliances and creating new ones. Indeed, while the actors are strategic, trying to advance claims that improve their political positions and accomplish some sort of policy goal, some claims may have unintended consequences, making cooperation much harder.

The really intriguing finding at the end is that ambiguity is the key to success. The Irish Good Friday Agreement was sufficiently vague that all parties could claim that their key concerns were met. Not only are well-networked brokers necessary but so too is a healthy dose of imagination to discover phrases and language that allow each side to think that it has won. However, this does raise the question of implementation: How do multiple actors follow an agreement that means a great many things? Does this just set up high expectations that cannot be met? I would guess that Goddard's response would be that the agreement itself may alter networks, creating lock-in and thus limiting defection down the road.

The book does three things very well, making it a model for graduate students writing dissertations: It presents the theory sharply, elaborating the causal logics and illustrating with a few figures the central concepts being deployed; it anticipates the likely criticisms and adeptly addresses them; and it clearly applies theory to cases. Goddard's cases are not just histories of events but careful application of the various concepts explained earlier to demonstrate the processes she considers to be important.

The author's focus on legitimation strategies does something that much ethnic conflict work fails to do—explain why some leaders are more successful than others due to the network nodes they occupy. Yet, the book still makes the same assumption as most of the work in this area (including my own)—that elites drive events and that the masses follow. Given the nature of negotiations, this makes sense most of the time. However, one of the strongest claims Goddard makes is that the British Conservatives essentially created Ulster as an actor through their rhetorical turn that was focused entirely on defeating Home Rule (Chapter 4). Although her claim that this rhetorical tactic broke the coalition ties among the Constitutional Nationalists, the Liberals, and the Republicans is convincing, the idea that the Conservatives brought Ulster into existence is less so, and, ironically for a book that stresses agency, deprives key actors in Northern Ireland of significant agency.

Goddard pays attention not just to the local parties in the negotiations but also to key outside actors. In the Northern Ireland case, she considers Ireland and Great Britain and their roles throughout the conflict. She does gloss over a key development in the divisibility of Ireland—the decline in Ireland's enthusiasm for irredentism. This makes sense, given her prioritization of how claims are made rather than motivations, but the changes in how the Irish see themselves and identify with their northern kin would seem to be more important than she gives credit. Similarly, a key difference between the two cases of Northern Ireland and Jerusalem are the number of actors and their interests. For the British and the Irish, continued conflict imposed significant costs. For many of the countries involved in the Israeli–Palestinian situation, there are relatively few costs and perhaps significant gains to be had for continued violence.

This book is an impressive contribution to our understanding of how conflicts become intractable and how territory becomes indivisible. It also is a very useful model for illustrating how to bridge rationalist and constructivist logics. Goddard's effort should be of use to both comparativists and international relations scholars inasmuch as her argument addresses the domestic dynamics of conflict but also the roles of outsiders as key actors in the development and reversing of indivisibility.