War and Power

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Ιn the run-up to the start of the Russo-Ukraine War in February 2022, numerous analysts from the U.S. Government and academic sources assessed whether Vladimir Putin would invade and, if so, what the likely outcome of a Russian invasion would be. The U.S. intelligence community accurately projected that Putin would invade, but the predictions about the war’s outcome turned out to be wrong. Russia did invade, but Ukraine successfully deflected the brunt of Russia’s aggression.

Why were the assessments about Russia’s prospects for a quick victory so far off? Was it an analytic failure stemming from faulty knowledge or flawed metrics? Do we need to develop a more holistic methodology for comparing the power of protagonists? War and Power develops and applies such a methodology or framework. 

Phillips Payson O’Brien, the author of this relevant and timely book, is a professor of history at the University of St. Andrews in Scotland. In addition, O’Brien writes a provocative Substack newsletter and does podcasts on contemporary security issues. His previous works on World War II—How the War Was Won (2015) and The Strategists (2024)—are acclaimed for their serious scholarship. This current project draws on these superb histories for insights. 

The central theme in War and Power is that God and fortune are not necessarily on the side of the biggest battalions. The war against Ukraine is just the latest example showing that there is more to success in war than having the most troops, tanks, planes, ships, or drones. The book is divided into two parts. The first half lays out a framework of five elements for assessing national power. States that possess these elements and successfully apply them are Full Spectrum Powers. O’Brien devotes a chapter to each element or pillar. The second half of the book strives to highlight critical distinctions during warfare. Here, the author employs examples from contemporary conflicts including the Cold War and Kosovo, as well as Iraq and Afghanistan. 

O’Brien finds fault with the notion of Great Powers, which he finds places a few states on a pedestal and misrepresents the value of allies. Admittedly, the term “Great Power” comes with hints of hubris and relegates the majority of states to a second tier or worse. But it also relates to the historical impact of powerful states and empires that have shaped history. O’Brien’s preferred substitute is Full Spectrum Powers, a concept that suffers from terminological defects and a strange oversight. While the term “Great Powers” connotes a rather exclusive club of major states, it implies scale and reach, not just breadth. Many nation-states have some capacity in most of the various elements of national power—think of capable middle powers today, such as France and the United Kingdom.

The first pillar of the spectrum is economic and technological strength: “The states that have been the most powerful over the past two centuries” and dominated have been “the economically largest and most technologically advanced.” As Paul Kennedy’s classic The Rise and Fall of Great Powers notes, economic and financial potential are important in tracing the transitions of great powers. 

As the second pillar, O’Brien’s framework includes leadership and how the personalities of political leaders influence policy. This also includes how political culture and social conditions may restrain critical conditions that lead to war. War and Power’s exploration of the intercession of leaders who are all too human is regrettably unique in measures of power. But the study of individuals is rewarding because, as articulated by Hal Brands in The New Makers of Modern Strategy, “it is people that formulate and execute strategy, and it is through their ideas and experiences that we can best comprehend the unrelenting demands of those tasks.” 

History shows that competition between powerful states often juxtaposes very different societies and enabling structures. This is the author’s third component, and it addresses social values, culture, and beliefs. The reference to structure entails government agencies, bureaucracy, and power centers. The social dimension of strategy is often overlooked, a point that the late Michael Howard made years ago. More recently, researchers have examined the importance of society during periods of strategic competition and renewal. Competitive societies tend to be open, pluralistic, full of intellectual energy, and committed to learning and adapting, and they have a common sense of their own role in the world. This complex mosaic is consistent with O’Brien’s application. 

The penultimate factor for the proposed framework is the military, or more accurately the construction of a military. Here, the author offers a bold observation: “[T]he constituent elements of a power tell us more about how effective a military will be than the raw numbers of equipment or doctrine.” In short, the strengths and weaknesses of a military will reflect its country’s political leadership, social system, and its technological capacity. O’Brien contends that if you want to know how a war will develop, “look at the powers involved as possessing different military systems, and examine the factors that will govern not only how those systems will operate at first, but how they can be regenerated, adapted, and improved as a war goes on.” 

While the author grasps the importance of advanced technology, he offers little advice on how to shape a military. For more detail on how Full Spectrum Powers have adapted their armed forces in the face of disruptive technologies, readers should consult The Origins of Victory by the defense strategist Andrew Krepinevich. 

The final dimension of Full Spectrum Powers deals with alliances. “An alliance of states that work together,” O’Brien finds, “can be mutually supportive and probably greater than the sum of its parts. Such alliances won World War I, World War II, and the Cold War.” Here the author cites British diplomacy as part of the Entente Cordiale before World War I as “a textbook case” for diplomacy. From London’s point of view surely it was a success, but the British Cabinet’s refusal to publicly commit to Belgian sovereignty and France’s security made a German intervention more likely. London’s desire to retain British freedom of action undercut the Entente’s deterrence against Berlin. 

O’Brien’s suite of dimensions appears incomplete. Readers will be surprised by the absence of any mention of information; here, the “I” is missing from the heuristic DIME (diplomatic, informational, military, economic) model. The importance of connectivity, content, and cognition should be noted given today’s fast-paced information environment. The author’s conception of what constitutes power in the “full spectrum” should be extended to account for nonkinetic sources. For a comparative analysis on national power in this enabling dimension in competition, see National Defense University Press’s Strategic Assessment 2025 (ed. Thomas F. Lynch III). 

Despite the author’s holistic approach and examples, the book does not appear to generate definitive solutions to the crucial issue of prediction or foresight. O’Brien’s own case study on Ukraine is revealing. Few observers would have credited the amateur Volodymyr Zelensky with Churchillian qualities in competition with the experienced and ruthless Vladimir Putin. Few observers would have had a sufficiently strong grasp of military reforms and security assistance to Kyiv since 2014 to judge that it could withstand a conventional invasion from a neighbor with thousands of tanks and a robust air force. In economics, the Russian gross domestic product is 11 times that of Ukraine, and Russia can ramp up manufacturing for armor, missiles, and other materiel. Ukraine’s entrepreneurial ingenuity and adaptability would have been quite hard to assess before the war but are obvious now. It is perhaps only in social cohesion and resilience that analysts might have sensed how Ukrainians would rally to defend their independence, given the Maidan demonstrations of 2014. 

The outcome of any war is difficult to predict. As any good student of Clausewitz realizes, war is inherently nonlinear. On War reflects that war is a nonlinear phenomenon, and that “similar causes do not always produce similar effects, and causes interact in ways unforeseeable even by the historically sophisticated”—like our author. Thus, any war may reflect different outcomes that will not be predicted with great accuracy. Much of the uncertainty comes from the unpredictable interaction of states, societies, economies, and military forces that O’Brien depicts over the last century and a half. 

We should learn to accept the reality that conflict is the realm of contradiction and paradox, not of rationality or precision analytics. No individual or algorithm will capture all the patterns of the past or eliminate uncertainty in future human affairs. That said, a framework that incorporates more than a military order of battle or static metrics appears extremely useful when formulating policy (or studying it). 

While Paul Kennedy will not be retitling his classic The Rise and Fall of Great Powers anytime soon, this splendid book is just as important. War and Power manifests a nuanced grasp of 20th-century wars, especially the complexities of two world wars. The book has particular utility for top-level joint professional military education students because of its informed exploitation of the past to demonstrate the dynamic interaction of the instruments of national power. O’Brien reminds us that wars are not necessarily won by the state with the largest army, the biggest missile inventory, or the most exquisite technology. Students of war must evaluate all the elements of power and anticipate their interaction. War and Power illuminates the past and guides serious students of war into the future.