Why does the settlement of some civil wars result in long-term peace, democracy, and prosperity whereas other resolutions lead to instability, authoritarian rule, and relapse into violence? In her latest and most compelling book, Monica Duffy Toft turns the well-established literature on civil wars on its head by making three principal claims, each more provocative than its predecessor. First, Toft argues that both the normative bias and the academic emphasis on the negotiated settlement of civil wars are deeply misguided. Less than 20% of civil wars since 1940 have ended as a result of negotiations. Second, outright victory by one party to the conflict is not only the most common means of resolving civil wars but also the most durable and thus, arguably, the most responsible way of addressing these conflicts inasmuch as wars resolved by military victory have been half as likely to reignite as wars ended by negotiation. Third, of the civil wars that have ended in this decisive manner, those in which rebels were victorious have proven nearly three times as durable as those won by governments.

Securing the Peace is impressive not only by virtue of the boldness of the claims proposed but also due to the careful blending of tools that the author employs to back her arguments. Key hypotheses are initially substantiated by means of a series of statistical analyses that correlate the means of civil war termination with the durability of peace, long-term changes in levels of democracy, and economic growth. Causal validation is attained in a series of meticulously selected and elegantly crafted case studies that highlight the differences of resolution achieved through negotiation, government victory, or rebel victory. The cumulative effect of this multimethod analysis is thoroughly persuasive.

The lynchpin of this argument is the notion of “mutual benefits, mutual harm”: Incentives designed to appease the vanquished ought to be combined with credible threats to punish combatants should these choose to resume fighting. Various modes of civil war resolution can be placed on a two-dimensional continuum, ranging from negotiated settlements (high benefit, low harm), through cease-fires (neither benefit nor harm), to government victory (low benefit, high harm). Only civil wars ending in rebel victory display the winning combination of high benefit and high harm that can ensure long-term stability. Whereas victory by incumbents can lead to further repression of the rebellious population, victorious rebels tend to enjoy popular legitimacy as a precondition to victory. This social support, combined with exclusive access to state resources and a need for international recognition, has led former rebels to set relatively liberal political agendas (pp. 47–48).

Toft challenges the conventional wisdom by thoroughly reassessing the literature on civil war resolution. Rejecting the unicausal explanations of both economists and realists, she proposes a synthesis in which combatants are motivated by a combination of greed and fear. Contra rationalists and neoliberal institutionalists, she argues that neither the commitment problem nor flawed peace terms can explain the weaknesses of so many negotiated settlements. She critiques both theories that pin the blame for war recurrence on spoilers and those who place their hopes for stability in third party guarantors.

Instead, Toft argues, the enduring resolution of civil wars requires the formation of a stable and peaceful state that can prevent the reemergence of forces loyal to former belligerents (p. 37). The key to success, then, is security sector reform (SSR), the neutralizing of nonlegal combatants, the reconstitution of military, paramilitary, and police forces, and the implementation of judiciaries and executives to oversee those forces. In contrast to the demobilization strategy emphasized by traditional peace makers, SSR should seek to retrain and retain existing military and police forces to ensure effective governance and stability (pp. 19–21).

The case studies that form the core of the volume offer a comprehensive qualitative analysis of this argument. The Salvadoran civil war functions as a “least likely” case, a negotiated settlement that has endured because it included comprehensive provisions for SSR. In Uganda, rebel victory led to a stable peace because the new government took care to permit opponents to participate in governance, thus correcting for the harm-to-benefit imbalance that might otherwise result from a decisive victory. The relapse of Sudan into conflict after its first civil war was due to lack of SSR in the 1972 peace agreement, a failure that may well recur unless SSR provisions in the peace agreement of 2005 are implemented in full. In a concluding analysis, Toft offers a scathing critique of the U.S. de-Baathification policy that contributed to Iraq's devolution into civil war.

Given its controversial thesis and succinct presentation, the volume also holds great promise for future research. For example, Toft's diligence in selecting cases that display variation in both independent and dependent variables means that only one of the four case studies demonstrates the positive causal argument at work: Only in the chapter on Uganda are the effects of rebel victory traced fully to the desired outcome, lasting peace. Given the sensitivity of any statistical analysis of civil wars to disagreements about definitions, coding, and variable operationalization (pp. 57–58), additional qualitative case studies could contribute a great deal of insight to this thesis.

Future research might also shed light on the precise relationship between the book's empirical and normative claims. If both rebel victory and security sector reform are said to be conductive to postwar peace and stability, what exactly is the relationship between the two? Do victorious rebels always implement SSR, as the author documents in Uganda, or might their success obviate SSR by offering alternative carrots and sticks to former combatants? Understanding this relationship is important, since the benevolent effects of rebel success are not always conducive to policy implementation, as U.S. decision makers in Iraq and Afghanistan would readily concede. Even where rebel triumph is amenable to manipulation by third parties, the argument runs the risk of endogeneity: It may well be that rebels are only capable of winning where the requirements for postwar stability (such as popular resentment of repressive rule and broad-based support for liberal governance) are already in place.

Extensions of this project might also clarify the argument's boundary conditions. Toft argues that negotiated settlements that incorporate SSR provisions can emulate the benefits of military victory while avoiding many of its costs (p. 50). Are those the only viable alternatives? How do these two factors interact with familiar variables known to affect the onset, duration, and resolution of civil wars, such as the presence of conflict resources, rugged terrain, involvement of diaspora communities, intervention by great powers or neighboring states, or the salience of ethnic and religious cleavages?

Securing the Peace offers an analysis that is as bold as it is persuasive. Toft teaches us that negotiated settlement should not be treated as the default option for resolving civil wars. Scholars and policymakers will find this to be a lucid, compelling, and important lesson. Peacemakers, who may inadvertently prolong the very wars they seek to resolve, will ignore this warning at their peril.