Acting Alone: A Scientific Study of American Hegemony and Unilateral Use-of-Force Decision Making

  • Published

Acting Alone: A Scientific Study of American Hegemony and Unilateral Use-of-Force Decision Making by Bradley F. Podliska. Lexington Books, 2010, 272 pp.


The use of unilateral force by US presidents is a much maligned, but little studied, phenomenon. While there are no shortages of texts and articles noting (and usually condemning) unilateral action, few in-depth studies on why a president would decide to commit to such an unpopular activity exist. With Bradley Podliska’s Acting Alone, this under-researched aspect of foreign policy decision making finally receives the rigorous social scientific analysis it deserves. In this monograph, Podliska, an analyst for the Department of Defense, examines the factors specifically connected to the decision to use unilateral force, considering how a president would weigh the potential problems with multilateral action against the benefits of unilateral action. Through statistical analysis, experimental methodology, and case studies, he explicates why presidents would find the decision to “act alone” so appealing among given options.

There are two major theoretical aspects of note in this text. The first is Podliska’s analytic separation between (a) a president’s decision to use force and (b) the decision whether to use this force in a unilateral or multilateral manner. While this may seem a simple distinction, the author rightly notes that most previous research blurs these two decisions. More to the point, information and pressures that are highly relevant for the first decision may be less relevant, or not important at all, for the other (and vice versa). In focusing on the latter, Podliska provides valuable insight into why presidents decide to act unilaterally despite the widespread belief that such actions are inherently unpopular.

This brings us to Podliska’s second major theoretical contribution: his explanation of the factors that lead presidents to decide between unilateral and multilateral action, decision (b). Reviewing the costs of multilateralism (in terms of burden sharing, inaction, collaboration/cooperation, reciprocity, and legitimacy) and the benefits of unilateralism (lower costs, public ambivalence on multilateralism, and sole reliance on the US military), Podliska presents an expected utilities model for unilateral use-of-force decision making. Major factors include the relative military power gap between the United States and its opponent as well as situational factors, such as conflicts occurring within the Western hemisphere, thus touching on the Monroe Doctrine. The first element, on military power, focuses on military revolutions. In Podliska’s argument, the hegemonic status of the United States needs to be understood in the context of the fast-paced military revolutions as well as the current revolution in military affairs (RMA). This revolutionized military factor incorporates military preponderance, technology, and force deployment as aspects of importance. Presidents consider the comparative gap in military revolutions between the United States and opponent states, as well as situational factors—hemispheric location, national security versus humanitarian intervention, and the like—when deciding how to act. Under this model, presidents will decide to use force unilaterally in cases where the gap is large and situational factors increase the saliency to US security. In cases of smaller gaps and less immediate security concerns, they are more likely to opt for multilateral responses. To help analyze the model, Podliska provides an empirical contribution, the Composite Indicator of Military Revolutions (CIMR) dataset. While useful for unilateral use-of-force decisions, this dataset has broader applicability as an alternate measure of military power.

The theoretical and empirical contributions of this book are strong. Moving away from the hyperbole and polemic that surround unilateral use-of-force decisions, Podliska’s scientific analysis of what these decisions entail is a welcome addition to the literature. While some of the statistical results are a bit weaker than one would prefer, the additional evidence from experimentation and case studies (focusing on the Bay of Pigs debacle, George H. W. Bush’s invasion of Panama, and the 1991 Gulf War) strengthens the book’s main thesis. As such, this study requires researchers to consider seriously, first, whether our assumptions of the costs of unilateral use-of-force are accurate and, second, the role of revolutionized militaries in presidential decision making.

However, there are some weaknesses in this text. The most notable issue is the model of unilateral use-of-force decision making that Podliska presents. While useful as a starting point, it is underspecified and overly broad in some ways. A more rigorous “mapping” and comparative strength/importance between the various factors influencing the president’s decision would have helped. While Podliska is right to separate the use of force and type of force (unilateral vs. multilateral) decisions analytically, one assumes that some path dependency exists between these two choices. Even if gaps in military power and situational factors are the most relevant issues for the unilateral/multilateral decision, his model needs some recognition of how factors influencing the initial decision may shape the available “space” for choices in the latter. However, as his model was intended to present a new aspect in presidential decision making and makes no claims to absolute comprehensiveness, this weakness is minor and provides fruitful avenues for future research.

Acting Alone is a valuable contribution to the social science literature on foreign policy decision making, even with the noted weaknesses. Anyone interested in presidential use-of-force decisions, analysts concerned with the role of military revolutions in presidential decision making, and scholars examining multilateral use-of-force decisions would all profit from this text.


Phillip W. Gray, PhD

US Coast Guard Academy


"The views expressed are those of the author(s) and do not reflect the official policy or position of the US government or the Department of Defense."