Jon Western's book joins an expanding list of studies on the sociopolitical context that shapes U.S. decisions to resort to force abroad. Most such studies reflect an appreciation that, core assumptions of realpolitik aside, these decisions are the resultant of various vectors of domestic power and preference, vectors that often point in different directions. Some of these studies directly address the incentives and constraints that public opinion places in the path of democratic leadership. Others analyze the manner in which actors within the higher echelons of the power structure interact to produce national policies. Western's study encompasses both levels of analysis, examining how the interaction of elites and public affect the likelihood that the United States would intervene militarily in other nations.

At their best, such studies display several attributes. One is originality, asking novel and productive questions and directing our gaze toward areas that had previously not been illuminated. The best studies are analytically powerful, providing a range of explanations and predictions from a compact foundation of assumptions and propositions. The research presented in such studies (whether qualitative or quantitative) adequately reflects the hypotheses that are being tested and supports, as fully as possible, the conclusions that are drawn. Falling short of the best studies, but nevertheless proving useful, is work that organizes and interprets a large body of information on a substantively or theoretically interesting topic, while not rising to the qualities outlined here. This book is of the second sort.

The theoretical framework departs from the entirely reasonable premise that decisions to use military force are not autonomously taken by those at the very pinnacle of political authority, that they result from the push and pull of various elites with often divergent views on the desirability of the military option. These elites engage in a process of advocacy, the outcome of which is largely determined by the beliefs of the president, the degree of cohesion within the executive branch, the distribution of information and resources among the advocacy groups, the role of the news media, and the duration of the crisis (shorter durations favoring the presidency). The principal advocacy groups are identified as selective engagers (who adopt a view of international politics steeped in realpolitik, while believing that the use of force should be prudently selective), hard-liners (proponents of a very assertive military presence in the world), reluctant warriors (who dislike involvement in limited wars and are mainly to be found within the military establishment), and liberals (who believe in the primacy of international organizations and welfare interests, and who generally are anti-interventionist). Much of the relative success of these groups will depend on the credibility of the external threat and the presence of a compelling theory of victory, both of which increase public susceptibility to the group's arguments.

I doubt that many readers would quarrel with the view that all of these considerations matter. From a theoretical standpoint, though, one is entitled to complain on a number of grounds. To begin with, there is little in the aforementioned framework that is not fairly self-evident, meaning that the net contribution to our explanatory ability must remain modest, limited to the way in which information is organized while providing no breakthroughs. In any case, we are given no clues as to the relative causal impact of the various proposed categories; unable to discriminate between them, we have no basis for knowing what the precise causal assumptions are. Moreover, as no competing hypotheses are seriously offered, we have no grounds for estimating how well this framework performs compared to others, whereas if there are no serious rivals, then it is not obvious what the precise analytical contribution is.

The empirical research is comparative-historical, and information is grouped into the various categories that comprise the theoretical framework: The position of the four advocacy groups are scrutinized, and their impact is viewed within the context of their information and resources, presidential beliefs, and cohesion within the administration. The role of the media is examined and the consequences of crisis duration considered. The framework is applied to the decision not to intervene alongside of France in Vietnam, the 1958 intervention in Lebanon, President Ronald Reagan's decision to use military force in Grenada, the Somalia and Bosnian actions of the mid-1990s, and, finally, the decision to invade Iraq. Each case produces a summary on the domestic context of the intervention, while a concluding chapter pulls the various threads together. The overall conclusion is that competing beliefs by policy elites matter, as does the role of the presidency, the degree of cohesion within the executive branch, and the impact of the media.

One complaint is that these are statements that very few would have chosen to doubt; another is that there is no compelling reason why the conclusions must follow from the information provided—the two are compatible, but the conclusions could also be compatible with other assumptions. The issue is that in the absence of a) a statement of competing explanations and b) a set of clearly justified criteria that would cause propositions to be either confirmed or disconfirmed, we remain uncertain that the author's hypotheses have, in fact, been tested. It is not surprising to learn that domestic circumstances affect decisions on military intervention. What we really desire to know is how much they matter compared to objective international conditions and, also, how important the various domestic influences are relative to one another, but this is not the sort of information that this research design could provide.

One of the most interesting hypotheses concerns the link between the duration of a crisis and the relative power of the advocacy groups—the balance shifting away from those associated with the presidency as the length of the crisis increases—mainly because the president's initial informational advantage soon is lost. This book must mainly be read for the comparative history of intervention decisions that it provides. These are carefully described using a common organizational framework, and they convey, in an interesting manner, the various political complexities associated with decisions to use military force.