The essence of Gil Merom's argument in this book is that democratic strong actors cannot win small wars because these states are constrained by society to avoid the sacrifice—in both sustained and inflicted casualties—necessary to win: “My argument is that democracies fail in small wars because they find it extremely difficult to escalate the level of violence and brutality to that which can secure victory. They are restricted by their domestic structure, and in particular by the creed of some of their most articulate citizens and the opportunities their institutional makeup presents such citizens. Other states are not prone to lose small wars, and when they do fail in such wars it is mostly for realist reasons” (p. 15). Merom adds that “[e]ssentially, what prevents modern democracies from winning small wars is disagreement between state and society over expedient and moral issues that concern human life and dignity…. Achieving a certain balance between … the readiness to bear the cost of a war and the readiness to exact a painful toll from others—is a precondition for succeeding in war” (p. 19).

The argument reduces to the claim that in small wars, insensitivity to friendly casualties and a willingness to maximize violence against an opponent are necessary and sufficient conditions for victory; and that modern democracies are structurally constrained in both categories. The particular relationship between society and the state makes democratic strong actors too squeamish to win small wars.

Merom's work is a welcome addition to the three previous central works on asymmetric conflict—Andrew J. R. Mack's “Why Big Nations Lose Small Wars” (World Politics 27 [1975]: 175–200); Eliot Cohen's “Constraints on America's Conduct of Small Wars” (International Security 9 [1984]: 151–81); and my own “How the Weak Win Wars” (International Security 26 [2001]: 93–128). The book also engages a broader debate concerning ethics in international relations and the military and political utility of violations of the laws of war (Alexander Downes, “Targeting Civilians in War: The Starvation Blockades in WWI,” and Ivan Arreguín-Toft, “The [F]utility of Barbarism: Assessing the Impact of the Systematic Harm of Non-Combatants as a Strategy in War,” papers presented at the 105th Annual Meeting of the American Political Science Association, 2003.)

Mack's argument focused on the paradoxical implications of power on resolve to win: An asymmetry of power implied an inverse asymmetry of political vulnerability (domestic actors capable of thwarting an incumbent government's preferred policies) and that, combined with the assumption that weak actors would invariably use a guerrilla warfare strategy, explained why big nations lost small wars.

My own argument built on Mack's thesis to arrive at a theory of asymmetric conflict outcomes that relied on the notion of strategic interaction. I argued that there are two ideal-types of strategic approaches—direct and indirect—and that when these interact one way, wars are short and strong actors win. When they interact another way, however, wars are protracted and strong actors are much more likely to lose. My argument also built on Cohen's insights—now 20 years old—into why a powerful democratic state such as the United States might yet lose a small war. Cohen's biting analysis focused on the special demands of counterinsurgency warfare, and his argument rested on the causal impact—not of social restraint—but of a military's capacity to learn from its mistakes and then institutionalize important lessons so as to train and equip the sort of forces necessary to win small wars. Merom's argument supplements but in no way supplants this key cause of strong actor failure in small wars.

If my own theory has a weakness, it is that it does not concern itself—except in a peripheral and speculative way—with the important question of why actors choose the strategies they do.

Here is where Merom's thesis has the chance to make its strongest contribution to the nascent rebirth of asymmetric conflict research (itself intimately tied to questions of legitimacy and ethics in the use of armed force). Merom offers an explanation that focuses on the domestic-level constraints on actors seeking an ideal strategy, and his argument makes it possible to explain the puzzling case of a strong state pursuing political objectives using the wrong strategy and the wrong mix of forces. But there are three important problems with Merom's argument.

First, we have important examples of democratic strong actors initiating brutal strategies (or prodigiously expending soldiers) and still losing small wars (e.g., the French in Indochina, 1945–54, and the United States in Vietnam, 1965–73), as well as authoritarian regimes doing the same thing and losing (e.g., the Nazis in Yugoslavia, 1941–43, and the Soviet Union in Afghanistan, 1979–89). Merom would likely respond that although in Yugoslavia, Indochina, Vietnam, and Afghanistan the strong actor was in fact brutal, what was needed was pure genocidal brutality; and for reasons particular to each case, this did not happen. But this argument ignores three constraints that have nothing to do with societal pressure: the constraints that follow from the necessity of avoiding the risk of escalation to a world war; the constraints that follow from a sense that the utility of further brutality may be either marginal or even negative (it may cause friendly psychological casualties or provoke external intervention); and the constraints that follow from a common response to extreme brutality as a counterinsurgency strategy: moving base areas across interstate boundaries.

A second problem with Merom's argument is its insistence that extreme brutality pays. But the logic of this argument is equivocal, and the record of success in the use of barbarism is mixed at best (Arreguín-Toft, 2003). The best explanation for this recent historical development is something Merom's argument points to but that he overlooks: The same social changes—amounting to an expanding international norm—constraining the use of genocidal brutality by democratic strong actors also affected weak actors, transmuting their resistance against extreme cruelty and hopeless odds into glorious martyrdom.

Moreover, democratic states facing competent insurgencies have another option besides barbarism: conciliation. Britain succeeded with this strategy, which involves using economic incentives and political reforms to address an insurgency's legitimate grievances, in the Malayan Emergency of 1948. Cohen's analysis (1984) and mine (2001) also drive home the point that with the right mix of forces and strategies, democratic strong actors can win small wars without resorting to barbarism and without sustaining high casualties (the real cost of such campaigns is time).

Finally, Merom's thesis is not well tested. His research design ignores the success and failure rates of authoritarian states, states less constrained by 1) dependence of the state on society for military forces; 2) a general preference for measures short of war by society; or 3) the ability of society, through charismatic representatives, to alter the state's foreign policy or military strategy. It also cannot help us weigh the causal impact of other plausible causes of democratic state restraint in small wars.

These problems aside, Merom's account of the political vulnerability of democratic actors in small wars is both excellent and timely. How Democracies Lose Small Wars expands on Mack's description of why and how democratic strong actors are politically vulnerable, and offers a useful explanation of why democratic states choose the strategies they do, and why they stick to failing strategies even after they have received a clear indication that their strategy for victory is in fact failing.