The past two decades have taken us a long way toward defining international security, and both the scholarly and policymaking communities have been making a steady shift toward reconceptualizing security as something much broader than the absence of militarized conflict between or within states. In this book, Andrew T. Price-Smith explores the complex and salient link between the health of a population and state capacity. While some attention has been paid in the security studies literature to the relationship between elements of political instability, such as violent conflict and states' health achievement, the influence of health outputs on security has largely been ignored. Contagion and Chaos is thus unique in examining the effect of disease and pathogens on national security.

Price-Smith argues that the impact of epidemic disease works its way through various societal elements to subsequently undermine state capacity, which in turn generates threats to national and regional security. The first link in the chain of mechanisms through which disease affects security is domestic political unrest: As declining health outcomes compromise prosperity and population well-being, intrastate and intragroup violence increases. Disease proliferation further acts as a “stressor variable” to destabilize governing institutions and reduce the power and security of a state through a series of demographic, psychological, economic, and political repercussions. Society thus acts as an intervening variable in the effect of disease on state capacity, with capacity being “composed of various components, including fiscal resources, resilience, legitimacy, reach and responsiveness, coherence, autonomy, human capital, and coercive power” (p. 19). Moreover, certain particularly pernicious pathogens carry the ability to contribute to interstate disputes. Evidence for the negative effect of disease on state capacity is provided by means of case studies that focus on the effects of specific epidemics. Although the main focus of the book is the effect of disease on security, the author also addresses the potential negative influence of war on population health.

After carefully situating the subject of disease and security in ancient and modern political theory, Price-Smith conducts an exploration of the influence of four events of epidemic outbreak on key aspects of governance in affected states: the influenza outbreak after World War I, HIV/AIDS in Zimbabwe, mad cow disease in the European Union, and severe acute respiratory syndrome (SARS) in the Pacific Rim. For each of these cases, the author notes major socioeconomic and political consequences of these specific pathogens. The analysis suggests that “the morbidity and mortality generated by the influenza pandemic generated profound institutional sclerosis” (p. 81) in affected states, including deleterious effects on militaries and bureaucracies. In a more recent case, Price-Smith contends that HIV/AIDS has contributed “to demographic contraction, economic destabilization, and sclerosis in governance,” which “threatens the material interests of the state, and of Zimbabwean security” (p. 109). The chief negative impact of bovine spongiform encephalopathy (mad cow disease) occurred in the form of trade restrictions and subsequent tensions among trade partners, such as Japan, United States, Canada, and South Korea. The SARS epidemic led to mixed consequences; while it “posed a significant material threat to the prosperity, effective governance, and security of affected states” (p. 156), it also resulted in the formation of domestic and international arrangements to deal effectively with public health crises.

Price-Smith's case studies are informative and valuable in illuminating some of the linkages among epidemics, societies, and governance. However, the selection and treatment of the cases is more descriptive in nature than social scientific. In particular, the choice of cases is not properly justified on epistemological grounds. For instance, one of the criteria for case selection is that the “pathogen must have generated at least some disruption (economic, social, or political) within the population of five sovereign states” (p. 23), which indicates selection on the dependent variable that may bias the findings of the subsequent analyses. Not including cases in which pathogens did not result in perceptible changes in relevant indicators of the dependent variable raises the specter of missing key determinants of societal vulnerabilities that may be associated with certain outcomes, thus impeding our ability to derive policy prescriptions from the analysis.

Moreover, although four is a fair number for comparative case studies, the analyses do not provide appropriate comparisons among the cases. More importantly, they do not offer adequate explanations for the direct effects of extant sociopolitical and economic conditions in the countries under discussion. For instance, the discussion on page 95 acknowledges that although Zimbabwe and Botswana both have high HIV/AIDS rates, the societal effects of the epidemic on Zimbabwe are much greater. Such varying effects of the same pathogen in different states necessitate attention to important socioeconomic and political factors that may directly be affecting indicators of state capacity.

As a result, the case studies—while competent and thorough—do not convincingly explicate the direction of causality in the various hypothesized linkages among disease, societal issues, and state stability. Is it, in fact, the case that certain societies and states are more susceptible to epidemics? Does the answer to the impact of pathogens actually lie in state characteristics, rather than in the nature of the disease? Significantly more compelling is the argument in Chapter 7 regarding the positive effect of warfare on disease proliferation, which asserts that violent conflict “may be seen as malign not only in and of itself but also in its role as the progenitor and disseminator of disease” (p. 186). The mechanisms through which war increases disease are clearly outlined, with a cogent argument and brief discussions of specific diseases.

What Contagion and Chaos lacks in rigor it makes up for in eloquence and in its conscientious discussions of global issues associated with emergent epidemics. The main contribution of this book lies in pushing the boundaries of security studies, and taking us beyond traditional notions of national and international security. For that, it belongs firmly within the growing literatures in political science on human security, population well-being, and state fragility. The domestic and international effects of epidemics are of tremendous importance for a host of actors, ranging from individuals in a population to international organizations, and this book provides a valuable assessment of the role of disease in a globalized world.