Michael Desch's book engages a prominent question in the recent study of international security: Are democracies better at war than other regime types? The book is devoted primarily to an extended critique of what Desch calls “democratic triumphalism”—the argument that a) democracies have, in fact, proven to be remarkably successful at war, and b) this correlation can be accounted for either by the ability of democracies to select into wars that they are likely to win and/or by characteristics of democracy that make democratic countries more effective in the conduct of war. Importantly, he is equally critical of “democratic defeatism,” which claims that democracy is actually a hindrance in war. Making a conventional neorealist argument, he concludes that regime type plays only “a modest and inconsistent role” (p. 170) in explaining war outcomes.

While the relatively short first chapter of Power and Military Effectiveness addresses the democratic defeatism argument, it is clear that the main target of the book is democratic triumphalism, and in particular the work of David Lake, Dan Reiter, and Allan Stam. In Chapter 2, Desch reviews both the statistical evidence supporting the claim that democracies are better at war and examines the logic behind this claim. With regard to the evidence, he suggests that the data sets relied upon by Lake and Reiter and Stam mistakenly include some cases and miscode others. On the logic, Desch first dismisses the claim that democratic leaders make more prudent decisions about when to go to war either because they have better information available to them or because they face the prospect of future elections in which they may be punished for a poor decision. He is equally critical of a second causal logic suggesting that democracies are simply better at fighting wars than nondemocracies. According to this argument, democracies are wealthier, attract allies, are better at strategic evaluation, enjoy greater public support, and have more dedicated troops, but much of Chapter 2 is devoted to explaining why the author finds the logic behind each of these arguments unconvincing.

This book represents the continuation of a debate between Desch and his interlocutors begun in 2002 in the pages of International Security. Perhaps the book's most significant addition to that debate is the inclusion of lengthy case studies in Chapters 3–5 of the Russo-Polish War, Israel's various wars, and the Falklands War. Desch chooses these three cases because they are instances where a prominent alternative explanation focusing on military capabilities alone would have expected the democratic country to lose—“hard cases” for a realist. Employing a process tracing methodology, he endeavors to demonstrate that the causal factors forwarded by the democratic triumphalists cannot account for democratic victory in each case.

The book is strongest in its critiques of the causal logics behind the democratic triumphalist arguments. Desch is convincing in arguing that democratic leaders are not always better than leaders of other regime types at taking advantage of information available to them, nor do they necessarily feel constrained by the prospect of looming elections. His criticisms of the arguments that democracies are more effective on the battlefield are perhaps even more compelling. He ably argues that democracies may not exhibit all the various beneficial traits in conducting war that triumphalists ascribe to them, but he could have done more to show that autocracies are no better or worse. After all, democracies may not score as well as triumphalists would have us believe, but they may simply be better than nondemocracies, which are almost always their opponents in war.

Desch's earlier work on this subject has been criticized on methodological grounds. Most contentiously, he deals with cases of “gross mismatches” in relative capabilities simply by removing such cases from the data set. It should not be surprising, he contends, that democracies prevail when they are much more powerful than their adversaries, but such victories cannot simply be credited to the presence of democracy. Removing the gross mismatches leads to a significant reduction in the number of cases in the data set, which, triumphalists argue, is both unwarranted and serves unjustifiably to reduce the statistical significance of their findings. By subtracting such cases, Desch's critics claim, he has essentially eliminated the very evidence that would substantiate the selection effects argument. Instead, Lake and Reiter and Stam contend that military capabilities should simply be used as a control variable in the same way as any other control variable in a multivariate regression. In the end, Desch may have been better served by not making this methodological move. He still grants that democracies are relatively successful at war even after he reassesses the data set. The more damning critiques are the logical ones, for without a compelling causal logic, the statistical correlation alone should convince nobody.

Finally, one wishes that Desch was able to offer us a more convincing theoretical argument that does explain this statistical correlation between democracy and victory in war. The final chapter of the book seeks to explain what might account for the pattern of success of democratic states if it is not democracy. He identifies a tantalizing number of factors that might explain these victories—the balance of interests, the nature of conflict, nationalism, the balance of forces, geography, effective emulation of successful military practices, and levels of economic development—but he seems wary of too strongly endorsing any one of these arguments. Not surprisingly given his realist credentials, he is inclined to an argument focused on military power, but the literature on military effectiveness has suggested an imperfect relationship between national capabilities and war outcomes. In fairness, the purpose of this book is not to offer a comprehensive theory of military effectiveness, but what emerges clearly by the end is that explaining military effectiveness remains an important and incomplete research agenda.

For graduate students interested in questions of military effectiveness or the potentially distinctive behavior of democracies in international relations, Desch's book is invaluable reading, likely to prompt rich and important debates.