Few topics receive more attention from international relations scholars than grand strategy—especially U.S. grand strategy. Although critics occasionally question the utility of the concept, there is an enormous literature devoted to explaining how nations formulate, implement, and modify long-term plans in order to secure their interests in the context of limited resources, domestic politics, and adaptive rivals, among other constraints. Given the large volume of work on this subject, including studies by some of the field’s most prominent theorists and historians, it is increasingly rare to encounter path-breaking explanations for the way that grand strategies are devised, unique interpretations of well-known historical events, or novel recommendations for contemporary policymakers. It is fitting, then, that Christopher Hemmer’s American Pendulum has comparatively modest ambitions. In his own words, the author sets out “to examine some of the fundamental debates that have recurred in U.S. foreign policy, to explore how the temporary resolutions of those debates have shaped previous attempts of the United States to make itself more secure, and to analyze what can be taken from those policies and their results to better evaluate what U.S. grand strategy should be today and in the future” (p. 2). Judged against these worthy aims, the book is a success.

The story of U.S. grand strategy can be told in many different ways depending on the lens through which one chooses to look. To provide a framework for analysis, Hemmer emphasizes four issues that policymakers have continually wrestled with since the presidency of Theodore Roosevelt, when the United States truly became a global power. The first debate is unilateralism versus multilateralism. Throughout U.S. history, the willingness of the United States to work closely with other nations, to rely on distant allies to achieve its core objectives, and to accept foreign limitations on its freedom of action has varied substantially. The second debate is the perennial trade-off between values and interests, a choice that is often identified with idealistic democracy promotion versus hardheaded realpolitik. Here, Hemmer notes that values and interests are often intertwined and, from the perspective of most U.S. officials, mutually supportive. Consequently, he adopts Walter McDougall’s more useful distinction between the United States as a “Promise Land” that promotes its values by example and a “Crusader State” that imposes those values by force.

The book’s third debate explores the shifting boundaries of the U.S. security perimeter; that is, efforts to delineate which countries or regions have enough strategic value to merit American attention, effort, and resources—including blood and treasure. Drawing on the work of John Lewis Gaddis, who famously highlighted the difference between “perimeter” and “strongpoint” variants of containment during the Cold War, Hemmer asks whether policymakers believe setbacks in any corner of the globe will erode U.S. power and influence, or instead whether they conclude that certain geographic areas have significant geopolitical value. The final debate is whether or not leaders believe that time is on the side of the United States, which is a critical question that is overlooked or underplayed in most works. Put another way, do favorable trends dictate optimism about its prospects and caution in its foreign policy, or do unfavorable developments lead to pessimistic assessments and precipitous action?

This framework has its strengths and weaknesses. On the one hand, Hemmer effectively uses these four debates to anchor a broad survey of U.S. grand strategy that covers more than a century, beginning in the decade before World War I and continuing through the War on Terror. In doing so, he captures many of the key issues that policymakers have faced in the past, including whether or not the United States should bear the burdens of global leadership, how it should operationalize containment of the Soviet Union, and the challenges of devising strategy in the absence of an overarching threat. The four debates also provide the basis for a handful of reasonable grand strategy guidelines, such as skepticism of regime change and nation building given the high costs of these endeavors, the need for a deep understanding of potential threats in order to prioritize them adequately, and the risks of retrenchment from overseas commitments despite calls to pull back by proponents of offshore balancing. On the other hand, many of these debates will be familiar to readers. Unilateral versus multilateral approaches to foreign policy, the role of values versus interests in shaping those policies, and narrow versus expansive conceptions of the American security perimeter are all common themes in the study of U.S. grand strategy. By contrast, the question of whether or not time is on America’s side represents a genuine addition to the existing literature. Bringing this question into focus is undoubtedly the book’s single biggest contribution.

Due to Hemmer’s emphasis on history over theory, as well as his decision to privilege breadth over depth, it is not surprising that American Pendulum raises many intriguing questions that it does not fully answer. These questions touch on each of the book’s four debates. For instance, are disagreements over unilateral versus multilateral approaches to foreign policy influenced by specific issues or specific partners? Under what conditions is the United States more likely to embrace the role of promise land or crusader state? How are divergent views about America’s security perimeter reconciled in periods of resource plenty versus times of resource scarcity? And does it matter whether assessments of America’s long-term prospects are shaped by its relative power, the perceived appeal of its values, or the domestic stability of its adversaries, each of which appears to have played a dominant role at one time or another?

In addition, one topic that Hemmer hints at but does not really tackle is the possible interactions among the four debates. Yet it seems apparent that they are not independent of one another. For example, adopting a multilateral approach to foreign policy could drive the United States to define its security perimeter in the widest possible terms, whereas emphasizing values over interests might lead Washington into costly foreign adventures that create doubts about whether time is actually on its side. These are just two possible illustrations of some potentially complex interrelationships. Although analyzing them in detail would undoubtedly make the book unwieldy, they do suggest that the story of U.S. grand strategy is probably much more complicated than Hemmer suggests.

In the end, American Pendulum achieves what it sets out to accomplish. It offers a concise review of U.S. grand strategy, a lucid analysis of its central themes, and a sober guide for any future policymakers. It is an excellent introduction for readers who are new to this topic, whether they are students or professionals. And it provides a useful reminder that while much has already been written about U.S. grand strategy, there is still more work to be done.