Military History for the Modern Strategist: America’s Major Wars since 1861. Michael E. O’Hanlon. Washington, DC: Brookings Institution Press, 2023.

National security practitioners should study military history in width, depth, and context.[1] That was the opinion of Sir Michael Howard, one of the greatest military historians of the twentieth century, a founder of influential think tanks and policy journals, and an advisor to generals, admirals, and ministers in Cold War London.[2] Michael O’Hanlon occupies a similar niche in today’s Washington, D.C. The senior fellow at the Brookings Institution is an influential advisor to the national security elite with a reputation for deep expertise and careful judgment. Though O’Hanlon is a political scientist, he argues that military history can usefully inform current policy debates.[3] His latest work, Military History for the Modern Strategist: America’s Major Wars since 1861, attempts to do just that through a survey of over 150 years of U.S. military history. Because few have been more successful than Howard in yoking history to the service of policy, his dictum of studying the past in width, depth, and context provides a useful point of departure for assessing O’Hanlon’s book.

History in Width

Howard urged practitioners to study in width (perhaps better stated as breadth), because a wide perspective allows one to see which aspects remain constant and which change over time. In this respect, Military History for the Modern Strategist is generally successful. The first five chapters do offer a wide vista through a survey of the major modern American wars: the Civil War, the World Wars, Cold War conflicts of Korea and Vietnam, and the wars in the Middle East since 1991. In each chapter, O’Hanlon focuses on the operational level of war, though he deftly interweaves discussion of tactics and technology, strategy and policy, and civil-military relations and politics as appropriate. His descriptions and analyses of these conflicts are clear and balanced. Though readers already familiar with these conflicts might gain little in terms of new factual knowledge, even experts will benefit from the analytical framing of key decisions by civilian and military leaders. O’Hanlon’s consistent focus throughout the book on contingency—at what point things might have gone differently—is a particular strength. In short, this book successfully delivers what the sub-title promises: a concise discussion of America’s major wars since 1861 through the eyes of an experienced analyst.

O’Hanlon’s primary purpose, however, is not to judge past practitioners but to inform those in the present. He even situates the book in the context of “integrated deterrence” from the 2022 National Defense Strategy.[4] With respect to influencing current debates, Military History for the Modern Strategist falls short in respect to breadth. One of the most pressing questions today is the extent to which the Department of Defense should narrowly focus on large-scale conventional conflict, particularly with Russia and China, at the expense of what has variously been called “gray zone,” “hybrid warfare,” or, within current joint doctrine, “adversarial competition.”[5] As one who personally supports the increased focus on “big war,” I contend that it is all the more important to use history as an intellectual counterweight to ensure the risks—and there are always risks—are explicitly acknowledged and accepted rather than simply ignored. When following Howard’s advice to study history in breadth, the wide vantage invariably takes in cases that challenge the prevailing conventional wisdom, whatever that might be; history in breadth whispers warnings into the ears of the powerful, reminding them of the many ways that events can confound, surprise, and wreck seemingly well-conceived plans. Indeed, the danger of hubris is one of O’Hanlon’s well-chosen themes throughout this book.

Due to O’Hanlon’s stature within the national security community, it is unfortunate that he did not take the opportunity to frame this important debate. By limiting Military History for the Modern Strategist to major wars, he implicitly endorses the present trajectory without making a larger argument for its correctness. Yet experience suggests that the debate will take place regardless. In reaction to similar choices privileging preparing for major wars over unconventional conflicts made after Vietnam, then-Major Daniel Bolger wrote in 1989 of the United States actually having two armies, one devoted to major conflict and one to shadow fights on the periphery. Bolger’s strong preference was for the latter, which he regarded as the truly decisive force; the larger, more visible army of mechanized formations, he dismissed as a “parade-ground force.”[6] Significantly, the “two armies” device was not original to Bolger, but was an homage to a novel—The Centurions by Jean Lartéguy—describing similar fissures within the French Army of the 1950s and 1960s. History in breadth illuminates such recurring patterns.

Another example from that same period demonstrates both the importance of works like O’Hanlon’s and the perils of study in insufficient breadth. Russell Weigley’s The American Way of War: A History of United States Military Strategy and Policy, first published in 1973, was an unusually influential academic work within the military; the book was a staple not just in graduate and undergraduate history instruction, but also within professional military education. Weigley’s description of a U.S. military historically spoiled by riches, and so tending to a firepower-based model of warfare that was unartfully attritional and unthinkingly astrategic, resonated in the aftermath of Vietnam. Though a useful foil for military reformers, Weigley’s portrait was in many respects a caricature. Yet the eminence of Weigley was such that it was not until 2002 that historian Brian Linn noted both the significant flaws of Weigley’s muddled theoretical construct and that the narrative relied almost entirely on a selective history focused largely on the American Revolution, the Civil War, and World War II. Linn demonstrated that the patterns discerned by Weigley did not hold up even when applied to conventional conflicts like the Spanish-American War and World War I, much less the many other less conventional conflicts and uses of force.[7] In short, Linn highlighted that a narrow focus on a few cases can lead to skewed understandings of the past, particularly when they confirm our contemporary biases.

Antulio J. Echevarria II employs a wider vantage in Reconsidering the American Way of War: U.S. Military Practice from the Revolution to Afghanistan. As suggested by the title, Echevarria builds upon Linn’s critique of Weigley to offer a more nuanced appraisal of U.S. military history by examining all its uses, including those outside of major conflicts. That greater breadth yields more nuanced findings. Viewing U.S. military history through a narrower lens, O’Hanlon offers three major lessons for strategists: outcomes in war are not preordained; wars tend to be harder and more costly than policymakers anticipate; and American grand strategy is sufficiently strong to weather some setbacks. Those lessons are certainly sound, and strategists would do well to heed each of them. Collectively, they also make a strong case grounded in empirical historical evidence for O’Hanlon’s preferred grand strategy of “resolute restraint.” Yet there is more to be gained from a survey of so much history. In contrast, Echevarria’s final “Conclusions and Observations'' chapter offers provocative insights into the relationship of politics and strategy, the quality of U.S. military strategy, and how the  “American way of battle” has yielded both success and failure over the centuries. Though a full overview of Echevarria’s conclusions is beyond the scope of this review, it is worth noting his observation that the exigencies of domestic politics—contrary to Weigley’s contention of a norm of overwhelming and decisive force—has actually led the U.S. military to conduct operations and campaigns with only a slight quantitative advantage, at parity, or even outnumbered.[8] This insight sheds light on both recent experiences in Afghanistan and Iraq, as well as providing a useful starting point for considering potential conflicts with Russia or China.

History in Depth and Context

Howard’s framework of studying history in width, depth, and context was advice for a lifetime of study, not something a single volume can achieve. The difficult trade-offs facing authors and publishers are evident in a comparison of Military History for Modern Strategists with Reconsidering the American Way of War. Because Echevarria covers much more ground, his discussions of each case are far more cursory than O’Hanlon’s. In respect to depth, Military History for Modern Strategists does not provide the best guide to those interested in further reading in depth. History is an active field, yet O’Hanlon’s footnotes suggest a significant reliance on aging standard works from a previous generation (or two).

Similarly, Howard’s final element of context is not as applicable to a survey such as O’Hanlon’s. Context generally, though not always, is a by-product of greater depth. A brief remark in the preface, however, suggests that O’Hanlon might not entirely understand what history provides in this regard. In contrasting his self-described concise and conceptual approach, O’Hanlon suggests that the main reason why historians go into greater detail is “the courage, sacrifice, and drama of individuals and peoples trying to achieve victory and avoid defeat and death that inspires us at the human level.”[9] Many popular histories are indeed filled with “human interest” stories or additional layers of technical detail, such as the precise number and type of aircraft in some bombing raid. Hopefully, O’Hanlon does not believe that the only difference between a shorter or longer work of history is the inclusion of such material. If so, that incorrectly conflates detail with context.

The differences between detail and context are exemplified between a two-dimensional case study and a fully grounded history that reveals the many dimensions of a conflict. This distinction can be clearly seen in works like Frederik Logevall’s Embers of War: The Fall of Empire and the Making of America’s Vietnam, which is cited by O’Hanlon. Embers of War situates the decisions related to Vietnam within the entangling contexts of domestic and international politics. Logevall provides the context of that decade, particularly the imperatives of building and maintaining accord with NATO allies and the complex interplay of personalities and events, then the deepening U.S. involvement—despite the misgivings of so many who were responsible—is at least explicable. Overall, that lesson is consistent with O’Hanlon’s large themes. The modern strategist will indeed benefit from his overview of America’s major wars since 1861 and the warnings to remain humble and ready for the unexpected. Hopefully, however, readers also heed Howard’s advice and do not stop with O’Hanlon’s worthy volume, but continue to study history in width, depth, and context.

J.P. Clark is an associate professor of military strategy at the U.S. Army War College, where he teaches in the Basic Strategic Art Program. He is the author of Preparing for War: The Emergence of the Modern U.S. Army, 1815-1941. The views expressed are the author’s alone and do not represent the official position of the U.S. Army, U.S. Army War College, Department of Defense, or the U.S. Government.

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Header Image: Little Round Top, Gettysburg, Pennsylvania 2020 (Nehemias Mazariegos).

Notes:

[1] Michael Howard, “The Use and Abuse of Military History,” Royal United Services Institution Journal 107 (1962), 7.

[2] Michael Howard, Captain Professor: A Life in War and Peace (London: Continuum, 2006).

[3] Michael E. O’Hanlon, Military History for the Modern Strategist: America’s Major Wars Since 1861 (Washington, DC: Brookings Institution Press, 2023).

[4] O’Hanlon, x.

[5] U.S. Joint Staff, Joint Campaigns and Operations, Joint Publication 3-0 (18 June 2022), ch VI.

[6] Daniel P. Bolger, “Two Armies,” Parameters 19 (September 1989): 24-34.

[7] Brian M. Linn, “The American Way of War Revisited,” Journal of Military History 66 (April 2002): 501-533.

[8] Antulio J. Echevarria II, Reconsidering the American Way of War: U.S. Military Practice from the Revolution to Afghanistan (Washington, D.C.: Georgetown University Press, 2014), 162-177.

[9] O’Hanlon, viii.