There is a great deal of research indicating that democratic leaders’ choices about international conflict are constrained in ways that autocratic leaders’ choices are not. How do these constraints work? What kinds of wars do they prevent democratic leaders from fighting? Andrew Katz’s When Democracies Choose War seeks to provide new answers to these questions. Like some previous work, he focuses on the need to sustain public support for military action. However, rather than focusing on the democratic public’s sensitivity to casualties or its demand for military success, Katz focuses on the nature of the arguments national leaders and their critics offer in the course of public debate.

Katz argues that democratic leaders must win a rhetorical battle over the purpose of the fighting in order to sustain a military effort. To do so, they must offer a compelling account of the problem that the war is intended to solve, and why military action was necessary to solve it. They must convince the public that there were few alternatives to the use of force in order to solve a problem that cannot be overlooked. In order to end the war, it is not enough for opponents to convince the public that it is going badly. They must contest the official definition of the problem it was supposed to solve. They must also offer an alternative policy that can withstand criticism from supporters of the war. Arguments within the “marketplace of ideas” must fit into the liberal norms prevalent in democratic societies. Some appeals, such as the need to sustain a colonial empire, may once have drawn support from democratic publics, but no longer accord with these liberal norms.

Katz tests his argument by examining five wars waged by democracies: the French effort to retain its Indochinese colonies after World War II, the U.S. war in Vietnam under Richard Nixon, the 1982 British campaign to recover the Falkland Islands from Argentina, the 1982 Israeli invasion of Lebanon, and the 2003–2011 U.S. war in Iraq. In each case, Katz examines data on public opinion and media coverage of the wars. The data on media coverage are especially important because they reflect the arguments for and against the wars. He codes news articles according to whether they addressed the framing of the war, its conduct, or the performance of the leadership in it. Broadly speaking, Katz finds that wars had to be curtailed when the opposition successfully challenged the government’s definition of the problem the war was intended to solve. For instance, the French government was unable to sustain its colonial war in Indochina when imperial prestige proved incompatible with emerging liberal norms. By contrast, even though most of the public disapproved of the Bush administration’s handling of the Iraq War, the military campaign continued because the opposition was unable to successfully challenge the president’s definition of the problem. As Katz puts it, “the critiques of the opponents, at home and abroad, did not provide a counter-frame around which opposition to the president’s case for war could coalesce” (p.185). They stumbled first over the supposed need to disarm Iraq in the wake of the 9/11 attacks (pp. 185–186), then over the “Pottery Barn rule” that the United States could not abandon the country to the chaos that followed the U.S. occupation (p. 201).

Katz’s focus on the process of political debate is an interesting departure from most accounts of how democratic constraint works. The appeal of government and opposition political rhetoric surely makes a difference for sustaining or undermining public support for war. However, When Democracies Choose War raises several important questions for which it does not provide entirely compelling answers. First, Katz points out that claims of necessity are a particularly important way of setting up a successful frame for war (p. 215) but it remains unclear why these claims are successful in some cases but not in others. No doubt some conflicts are easier to present in this light, but there is no clear connection between the character of the war and the success of the appeal in the five cases Katz presents. Why, for example, were opponents of the Iraq War unable to challenge claims of necessity, while opponents of Nixon’s search for “peace with honor” in Vietnam were able to do so?

Second, while liberal norms are no doubt important for shaping the appeal of political arguments in a democracy, they are not the only considerations that do so. The book’s chapter on the 1982 Israeli invasion of Lebanon implicitly recognizes this fact, citing Michael Barnett’s argument that Israeli national identity includes liberalism, but also Judaism, Zionism, and the Holocaust (p. 139). If this claim is correct, then non-liberal appeals that accord with the other three elements might well find a receptive audience in the Israeli public. Other democracies are probably no different. Arguments rooted in national self-assertion, cultural superiority, or even racist ideas might well find an audience under some circumstances. We cannot assume that the liberal elements of national identity will always take priority simply because a state has democratic institutions.

Finally, while the intrinsic appeal of arguments about war matter, it is still likely that other considerations also influence their political success. The marketplace of ideas is not a level playing field for advocates and opponents of a war. For instance, powerful interests like the officer corps, the owners of media outlets, and, in the case of colonial wars, settlers, might all wield disproportionate influence. In addition to their direct influence over policy choice, they might be able to stigmatize and effectively rule out certain lines of argument, and to require the rhetorical acceptance of others. Given their influence over both political debate and policy choice, it makes sense to integrate the role of groups like these into accounts that link these two variables.

Overall, When Democracies Choose War is an interesting contribution to research on democracies and conflict. It identifies a potentially important way that democratic norms might constraint national leaders, as well as some ways in which leaders might overcome these constraints. More work remains to answer the questions it sets aside, but this provocative book is a good start.