Good books and research articles explicitly state and focus on simple yet counterintuitive theoretical questions. Ivan Arreguín-Toft’s recent book, How the Weak Win Wars: a Theory of Asymmetric Conflict, has this admirable quality. “Why do the strong lose to the weak?” is the opening sentence and motivating question. Briefly stated, Toft’s answer is that the weak prevail when they adopt a military strategy that exploits the weaknesses in the strong state’s strategy. In defending this thesis, Toft not only enhances our understanding of outcomes in asymmetric conflicts but also makes a positive contribution to a growing program on military strategy. Anyone interested in either of these topics will profit from reading this book.

As a product of the Chicago school of international relations, Toft follows in the footsteps of John Mearsheimer, Robert Pape, and Michael Desch and focuses on military strategy. Contrary to those who suggest that the weak defeat the strong for reasons related to regime type, arms diffusion, or greater motivation, Toft contends that a strategy mismatch is the key to understanding these otherwise surprising outcomes. To evaluate this hypothesis, Toft examines all militarily asymmetric wars in the Correlates of War database (1800-2003). He codes the strategy employed by each side, creates a variable for whether or not the strategies matched, and analyzes the relationship between the strategic interaction variable and the war outcome. In addition, he examines the logic of the argument in five case studies: the Murid War in the Caucasus, the Boer War, the Italo-Ethiopian War, the Vietnam War, and the Soviet-Afghan War.

While fully aware of the spectrum of military strategies, Toft groups the strategies for each actor into two general types. Strong actors employ either a conventional attack or barbarism approach, with barbarism including counter-insurgency, and weak actors can employ either a conventional defense or a guerrilla warfare strategy. It is worth noting that Toft allows actors to switch strategies throughout a war. For example, a strong state may start with a conventional attack but switch to a barbarism strategy during the war. After recording the strategy for each actor for each major phase of a war, Toft creates a variable for whether the strategies matched. Conventional attack matches conventional defense, and barbarism matches guerrilla warfare. This leads to the central hypothesis of the book: “when actors employ similar strategic approaches (direct-direct or indirect-indirect) relative power explains the outcome: strong actors will win quickly and decisively. When actors employ opposite strategic approaches (direct-indirect or indirect-direct), weak actors are much more likely to win …” (p. 18) Consistent with this expectation, he finds that strong actors win approximately 77 percent of same approach match-ups, but only 37 percent of opposite approach match-ups.

Toft also makes an effort to rule out some of the most likely alternative explanations. In light of research highlighting the importance of domestic political institutions, Toft examines whether regime type makes a difference. The regime hypothesis presented by Toft is that authoritarian regimes are more effective militarily, so they should be less likely to lose to weak actors. Toft also examines a complementary regime hypothesis: that democratic states are unwilling to bear the necessary burdens to triumph. Arms diffusion is a second alternative explanation raised by Toft. The arms diffusion argument is that weak actors may have access to modern weapons, thereby leveling the playing field. Toft evaluates this by examining whether a weak actor received outside assistance. The third alternative argument discussed is interest asymmetry. The argument here is that stronger actors have less interest in the fight and therefore are more likely to lose.

Of these three alternative explanations, the regime hypothesis is the most theoretically cogent, yet it is not fully examined. To evaluate the effect of regime type one would have to examine the regime composition of the warring dyad. This is not done. The arms diffusion hypothesis is difficult to examine systematically as one not only needs to determine if there was direct outside assistance, but also the quantity and quality of arms weak actors were able to obtain on their own. In Rulers, Guns, and Money: The Global Arms Trade in the Age of Imperialism (2007), the historian Jonathan A. Grant documents how arms industries in Britain, France, Germany, and Austria exported their wares around the world, even to countries with whom their governments were not friendly. Even without active support from another state, it is likely that weak actors have benefited from arms diffusion.

Toft’s argument leaves some important questions unanswered. To what extent are strategies endogenous? It is highly unlikely that actors choose military strategies randomly. This choice is likely a function of geographical features, the nature of technology, regime type, and the nature of the leader. Given that one can assess the influence of these factors ahead of time with some degree of confidence, we cannot easily dismiss some of the alternative arguments raised by Toft. For example, perhaps democratic states are less likely to employ barbarism strategies than non-democratic states.

While less central to the validity of the matched-strategy thesis, the story would be stronger if two other questions were addressed. First, conventional wisdom suggests that the weak win when they employ a guerrilla warfare strategy. Toft contends that guerrilla warfare is only likely to lead to success if the strong state does not employ a barbarism strategy. Since he only reports aggregate information on the strategic interaction variable, however, we cannot determine how often a weak state’s guerrilla warfare strategy has failed. Similarly, conventional wisdom, and work by Robert Pape on air power, suggests that barbarism will almost always fail. It would be interesting to know if Toft’s data supports this expectation. Second, it would be telling to know why some but not all weak states change to a winning strategy. One might conjecture that strong states have less freedom to shift strategies owing to institutional inertia and size. These factors should be less relevant in weak actors, yet not all of them adopt strategies that maximize their chances of winning.

Notwithstanding the importance of these questions, they also speak to the clarity and quality of Toft’s writing. These questions come to mind because the writing is exceptionally clear and the thesis is interesting. The bottom line is that Toft’s book is worth reading. It makes an important contribution to our understanding of asymmetric conflict and contributes to a growing literature on the importance of military strategy.

Mark Souva is Assistant Professor of Political Science at Florida State University.