What do you think?
Rate this book
War and Power: Who Wins Wars―and Why
'Phillips Payson O'Brien is one of our finest historical thinkers.' James Holland, author of Normandy '44
War and power are two of the most-widely discussed issues in all of human history, and yet they are, time and again, misunderstood — often disastrously so.
Whilst we might think the outcome of war is determined by so-called ‘Great Powers’ who dominate their opponents with their impressive size and military prowess, the reality of modern conflict, as renowned strategic historian Professor Phillips Payson O’Brien demonstrates, is very different. He urges us instead to look for ‘Full Spectrum Powers’.
For if we are considering how powerful a nation is and who will win a war, we need to think less about weapons, and more about the economies and societies that produce them; less about individual battles, and more about sustaining campaigns and alliances in which states operate.
Using fascinating examples from the late 19th century to the present day, War and Power explains how misunderstanding war and power has led to terrible, even preventable conflicts – such as the war in Ukraine – and how more accurate analysis can help us consider the potential conflict between the US and China.
War and Power provides a bold new way of understanding the dangerous world around us.
War and power are two of the most-widely discussed issues in all of human history, and yet they are, time and again, misunderstood — often disastrously so.
Whilst we might think the outcome of war is determined by so-called ‘Great Powers’ who dominate their opponents with their impressive size and military prowess, the reality of modern conflict, as renowned strategic historian Professor Phillips Payson O’Brien demonstrates, is very different. He urges us instead to look for ‘Full Spectrum Powers’.
For if we are considering how powerful a nation is and who will win a war, we need to think less about weapons, and more about the economies and societies that produce them; less about individual battles, and more about sustaining campaigns and alliances in which states operate.
Using fascinating examples from the late 19th century to the present day, War and Power explains how misunderstanding war and power has led to terrible, even preventable conflicts – such as the war in Ukraine – and how more accurate analysis can help us consider the potential conflict between the US and China.
War and Power provides a bold new way of understanding the dangerous world around us.
288 pages, Hardcover
First published August 28, 2025
63 people are currently reading
602 people want to read
About the author
Phillips Payson O'Brien
11 books90 followersPhillips Payson O’Brien is a Professor of Strategic Studies at the University of St. Andrews in Fife, Scotland, where he has taught since 2016. A graduate of Trinity College in Hartford, Connecticut, O'Brien earned a PhD in British and American politics and naval policy before being selected as Cambridge University’s Mellon Research Fellow in American History, and a Drapers Research Fellow at Pembroke College.
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 14 of 14 reviews
October 15, 2025
Key takeaways from this reading:
*Historically, economic power and technological development has trumped the physical size of a state and population. GDP and the purchasing power per capita of a nation can vastly guide war outcomes, which makes sense because a population that's starving isn't going to be at peak performance at the battlefront or at home. The relative resource abundance experienced by Germans in Nazi Germany at the start of WW2 compared to the rest of Europe backs this point.
*Short, decisive wars are a myth. Wars end when either side (and their allies) run out of resources and the battles need to stop so they can recoup. Individual battles cannot determine the outcomes of wars, but rather a complex interplay of a nation's morale, diplomacy and material resources (economic power that can directly be translated to military technology that can be fabricated, adapted and scaled up in production volume if necessary) can help explain outcomes.
*ALLIES matter a lot. Wars are rarely won by single entities acting alone, and rather, coalitions that can compile their resources and work together for a joint end-goal usually can persist through the end of the war. The author not only emphasizes the importance of execution of complex operations and machinery, but also the ability to recover+ maintain morale in a continual cycle and the multifaceted human element of war.
The language in this book was accessible to the average reader, but the organization of the arguments the author made was hard to follow. I felt like I was jumping around from subject to subject or between time periods (yes, warning this is not organized chronologically) and geographically (heavy focus on Europe, US and east Asia war history). The end goal is to relate how this new understanding of economic and technological power relates to the Russian occupation of Ukraine.
*Historically, economic power and technological development has trumped the physical size of a state and population. GDP and the purchasing power per capita of a nation can vastly guide war outcomes, which makes sense because a population that's starving isn't going to be at peak performance at the battlefront or at home. The relative resource abundance experienced by Germans in Nazi Germany at the start of WW2 compared to the rest of Europe backs this point.
*Short, decisive wars are a myth. Wars end when either side (and their allies) run out of resources and the battles need to stop so they can recoup. Individual battles cannot determine the outcomes of wars, but rather a complex interplay of a nation's morale, diplomacy and material resources (economic power that can directly be translated to military technology that can be fabricated, adapted and scaled up in production volume if necessary) can help explain outcomes.
*ALLIES matter a lot. Wars are rarely won by single entities acting alone, and rather, coalitions that can compile their resources and work together for a joint end-goal usually can persist through the end of the war. The author not only emphasizes the importance of execution of complex operations and machinery, but also the ability to recover+ maintain morale in a continual cycle and the multifaceted human element of war.
The language in this book was accessible to the average reader, but the organization of the arguments the author made was hard to follow. I felt like I was jumping around from subject to subject or between time periods (yes, warning this is not organized chronologically) and geographically (heavy focus on Europe, US and east Asia war history). The end goal is to relate how this new understanding of economic and technological power relates to the Russian occupation of Ukraine.
January 19, 2026
This book really provides a different perspective on war. It’s a perspective that ultimately rings true based on a reading of history. I really think about war and international politics in very different terms after reading this book. Our leaders would be wise to read this and start thinking about conflicts from this perspective. It would save our country and the rest of the world lots of blood and treasure.
January 26, 2026
In this revisionist exploration of modern warfare, Phillips Payson O’Brien explores how social, economic, and political power helps win wars. Looking at the “Great Powers” of the last two centuries, O’Brien attributes their military successes to their infrastructure and the many elements that keep massive war machines working, rather than to the large armies and decisive battles that dominate military historiography. Making an argument for “full-spectrum powers” that take all of these factors into account, O’Brien explores Napoleonic France to modern China to expand upon this new military history intellectual framework. Packed with detail and historical evidence, readers will definitely appreciate the lengths that O’Brien has gone to support his argument and provide examples for his larger intellectual framework. The book is informative without being dense or unreadable, and all sorts of military history lovers will greatly appreciate the depth of information and connections in this book. The book itself is well-structured and the prose is approachable, so this makes it a great book for expert historians and general readers alike. Well-written, packed with details, and informative, this is a brilliant new military history book from Phillips Payson O’Brien offering a complex and well thought-out framework to use while studying modern warfare.
Thanks to NetGalley and PublicAffairs for the advance copy.
Thanks to NetGalley and PublicAffairs for the advance copy.
September 20, 2025
Extremely interesting review of war and 'great powers' through, mostly the last two centuries. A much needed rehearsal that puts into context the successes and failures of the presumed hegemonic powers. And the clear impact of stupidity/ability in leaders and the lack of prediction capabilities by most of the military and political establishment to predict or even adapt to recent events such as the Ukraine-Russia war make a very worriesome prospect for the near future.
February 6, 2026
4 stars for the average reader, 5 stars for anyone involved in or interested in national security. I made the tactical blunder of listening to this book vs reading it. There were too many passages I wanted to highlight and think about later.
The book presents “a methodology for understanding national power and then what matters when that power is employed in the conduct of war.” Countries (and leaders) need to look at the variables that create power in peace, and how to regenerate and support that power in times of war. Serious strategy must start with a review of national strengths and weaknesses across the economic, technological, political, and social domains, not just order of battle tables. Logistics, the will of the people, and effective allies are also critical factors. The author uses many examples of past wars, and the current Russo-Ukraine war, to support his theses. Initial expectations of a rapid Russian victory in the war are an example of “experts” underestimating systemic and societal factors. O’Brien argues that better analysis of full spectrum power could have helped analysts and leaders anticipate Russia’s failures.
Paraphrasing a bit from the chapter on Allies: Alliances play an outsize role in determining events in war and peace. In peace allies are an asset from which the larger power can benefit (not rule or dominate). Domination can lead to an empire whose sum is less than the makeup of its parts. The Soviet “allies” were really vassal states that were a drain on the USSR; Western allies were mutually supportive and won WWI and II and the cold war, and he claims could win a war in the IndoPacific.
Wars often mutate from the original goals to something much different; political goals at the beginning of the war rarely survive to the end. “Sometimes simply winning the war is the greater end.” When looking at how a war might develop, leaders should look beyond what will happen when armies actually fight (standard war-gaming objectives) and instead look at how armies can continue to operate, be equipped, and regenerate.
Wars often begin because leaders misperceive their own power and that of their adversaries. Battles are not decisive. What matters are the underlying systems which reflect the real balance of power – economy, technology and logistics. Too many are interested in the “decisive battle," but few wars are won quickly or in the manner any of the opponents thought. What matters is outlasting the enemy, ensuring they can’t restock men, material, and will. America won all the battles in Vietnam but couldn’t stop the VC and NVA from regenerating their forces. The first Gulf War is an exception, but since the allied forces called an end to the war after forcing the Iraqis out of Kuwait perhaps it would not have been and exception if they had driven on Baghdad. (See the second gulf war and the ensuing conflict.) The Allied victories in both world wars were more about economic might and production capacity than generalship. He doesn’t cite the US Civil War, but that is another example.
O’Brien applies his argument to the Russia-Ukraine war. He argues that Russia’s failures in Ukraine reflect systemic shortcomings—corruption, rigid command structures, shallow industrial depth, demographic and economic constraints—vis à vis a Ukraine plugged into Western financial, technological, and intelligence networks. The book suggests that similar structural analysis is essential for thinking about a potential US–China conflict, where questions of supply chains, industrial resilience, societal willpower, and alliance architectures will matter more than military size.
The book presents “a methodology for understanding national power and then what matters when that power is employed in the conduct of war.” Countries (and leaders) need to look at the variables that create power in peace, and how to regenerate and support that power in times of war. Serious strategy must start with a review of national strengths and weaknesses across the economic, technological, political, and social domains, not just order of battle tables. Logistics, the will of the people, and effective allies are also critical factors. The author uses many examples of past wars, and the current Russo-Ukraine war, to support his theses. Initial expectations of a rapid Russian victory in the war are an example of “experts” underestimating systemic and societal factors. O’Brien argues that better analysis of full spectrum power could have helped analysts and leaders anticipate Russia’s failures.
Paraphrasing a bit from the chapter on Allies: Alliances play an outsize role in determining events in war and peace. In peace allies are an asset from which the larger power can benefit (not rule or dominate). Domination can lead to an empire whose sum is less than the makeup of its parts. The Soviet “allies” were really vassal states that were a drain on the USSR; Western allies were mutually supportive and won WWI and II and the cold war, and he claims could win a war in the IndoPacific.
Wars often mutate from the original goals to something much different; political goals at the beginning of the war rarely survive to the end. “Sometimes simply winning the war is the greater end.” When looking at how a war might develop, leaders should look beyond what will happen when armies actually fight (standard war-gaming objectives) and instead look at how armies can continue to operate, be equipped, and regenerate.
Wars often begin because leaders misperceive their own power and that of their adversaries. Battles are not decisive. What matters are the underlying systems which reflect the real balance of power – economy, technology and logistics. Too many are interested in the “decisive battle," but few wars are won quickly or in the manner any of the opponents thought. What matters is outlasting the enemy, ensuring they can’t restock men, material, and will. America won all the battles in Vietnam but couldn’t stop the VC and NVA from regenerating their forces. The first Gulf War is an exception, but since the allied forces called an end to the war after forcing the Iraqis out of Kuwait perhaps it would not have been and exception if they had driven on Baghdad. (See the second gulf war and the ensuing conflict.) The Allied victories in both world wars were more about economic might and production capacity than generalship. He doesn’t cite the US Civil War, but that is another example.
O’Brien applies his argument to the Russia-Ukraine war. He argues that Russia’s failures in Ukraine reflect systemic shortcomings—corruption, rigid command structures, shallow industrial depth, demographic and economic constraints—vis à vis a Ukraine plugged into Western financial, technological, and intelligence networks. The book suggests that similar structural analysis is essential for thinking about a potential US–China conflict, where questions of supply chains, industrial resilience, societal willpower, and alliance architectures will matter more than military size.
December 24, 2025
The prevailing model used by political theorists for understanding international relations is a theory of behaviour called neo-realism: the idea that states act as coherent entities (you can talk about "America" or "Iraq" doing things) and pursue a self-interested path to maximise their relative power over time (not only are "America" and "Iraq" agents in the world, they're cleverly doing what's best for them all the time).
If this sounds an awful lot like the basic assumptions of and fundamental problems with the study of economics and output of economists, you're on the right track.
It's a truism among historians that, for precisely the reasons listed above among others, the output of political theorists is worth markedly less than the paper it's printed on. The technical term—I believe originally from engineering—is "worse than useless". This is for reasons that are self-evident and bone-deep among historians but perhaps not immediately obvious to normal people and clearly not obvious to the political theorists, who—despite having a worse predictive-success ratio than a chimpanzee playing darts—continue busily producing their nonsense assessments and spouting their absurd analyses.
A notable example is that in the lead-up to February 2022 the only people correctly predicting that Ukraine would resist Putin and resist effectively were not political theorists (Foreign Affairs, probably the peak outlet of the political theory establishment at large, predicted a war over in weeks) or defence specialists (General Mark Milley, the most senior officer in the US armed services and principal military advisor to the president, predicted a war over in hours if not minutes), but historians.
O'Brien bridges the gap brilliantly, arguing simultaneously that a focus on extant military assets ("how many tanks have they got?") the constant preoccupation of military professionals, and that a belief in rational independent actors ("what maximises their relative advantage?"), the simplistic focus of political theorists, blinds both to the actual dynamics of power and conflict between states. He grounds his argument in several historical examples, showing how the tools used by political theorists and defence analysts could not predict either the course or the outcomes of the First World War, Second World War, Vietnam War, the Soviet invasion of Afghanistan, or indeed the present war in Ukraine.
It's not exactly gripping reading, but O'Brien's prose is lucid and fast-moving. It's a rare pleasure to see an entire discipline and structure of theory and received wisdom dismantled so unequivocally in such a brief and comprehensive way. In its place, O'Brien posits a tiered theory of mass, structure and leadership that aligns closely with the nuanced and interwoven way historians traditionally come at interpreting the past. Unfortunately, the people who'd need to buy this new theory in order for it to have an operative impact are the same people who seem satisfied with the terrible predictive power of their current analytical tools (Mark Milley kept his job for well over a year after his disastrous policy guidance on Ukraine, for instance); it seems unlikely to have much impact.
If this sounds an awful lot like the basic assumptions of and fundamental problems with the study of economics and output of economists, you're on the right track.
It's a truism among historians that, for precisely the reasons listed above among others, the output of political theorists is worth markedly less than the paper it's printed on. The technical term—I believe originally from engineering—is "worse than useless". This is for reasons that are self-evident and bone-deep among historians but perhaps not immediately obvious to normal people and clearly not obvious to the political theorists, who—despite having a worse predictive-success ratio than a chimpanzee playing darts—continue busily producing their nonsense assessments and spouting their absurd analyses.
A notable example is that in the lead-up to February 2022 the only people correctly predicting that Ukraine would resist Putin and resist effectively were not political theorists (Foreign Affairs, probably the peak outlet of the political theory establishment at large, predicted a war over in weeks) or defence specialists (General Mark Milley, the most senior officer in the US armed services and principal military advisor to the president, predicted a war over in hours if not minutes), but historians.
O'Brien bridges the gap brilliantly, arguing simultaneously that a focus on extant military assets ("how many tanks have they got?") the constant preoccupation of military professionals, and that a belief in rational independent actors ("what maximises their relative advantage?"), the simplistic focus of political theorists, blinds both to the actual dynamics of power and conflict between states. He grounds his argument in several historical examples, showing how the tools used by political theorists and defence analysts could not predict either the course or the outcomes of the First World War, Second World War, Vietnam War, the Soviet invasion of Afghanistan, or indeed the present war in Ukraine.
It's not exactly gripping reading, but O'Brien's prose is lucid and fast-moving. It's a rare pleasure to see an entire discipline and structure of theory and received wisdom dismantled so unequivocally in such a brief and comprehensive way. In its place, O'Brien posits a tiered theory of mass, structure and leadership that aligns closely with the nuanced and interwoven way historians traditionally come at interpreting the past. Unfortunately, the people who'd need to buy this new theory in order for it to have an operative impact are the same people who seem satisfied with the terrible predictive power of their current analytical tools (Mark Milley kept his job for well over a year after his disastrous policy guidance on Ukraine, for instance); it seems unlikely to have much impact.
February 1, 2026
I went into this book convinced it wasn’t for me. I don’t usually enjoy nonfiction, and I’ve always thought history wasn’t my territory. This book challenged both assumptions, mainly through how clearly it explains the concept of power and war rather than simply recounting events.
What stood out was the way the author breaks down the great power concept and shows how wars are shaped by long-term structures, leadership, and limits, not just battlefield strength. Seeing different conflicts connected through the same underlying patterns gave me a new way of understanding history, and that perspective felt genuinely fresh.
It’s not always an easy read. The pacing can be heavy, and I sometimes had to slow down to keep up, which comes with the territory of nonfiction and historical analysis. Still, the arguments are clear enough that the effort feels worthwhile.
This book didn’t turn me into a nonfiction devotee, but it did change how I think about war and power, and that makes it a read I’m glad I picked up.
What stood out was the way the author breaks down the great power concept and shows how wars are shaped by long-term structures, leadership, and limits, not just battlefield strength. Seeing different conflicts connected through the same underlying patterns gave me a new way of understanding history, and that perspective felt genuinely fresh.
It’s not always an easy read. The pacing can be heavy, and I sometimes had to slow down to keep up, which comes with the territory of nonfiction and historical analysis. Still, the arguments are clear enough that the effort feels worthwhile.
This book didn’t turn me into a nonfiction devotee, but it did change how I think about war and power, and that makes it a read I’m glad I picked up.
January 20, 2026
The author paints a picture of American weakened dominance, resulting from damaged and destroyed alliances, lack of moral leadership, a deeply polarized society, and a the turn towards a service economy, rather than an economy with a strong industrial and manufacturing base. We are on the road to perdition.
October 28, 2025
offers a provocative reevaluation of war, arguing that leadership, society, and alliances often matter more than sheer military might. It is challenging to follow in some places, but the inclusion of historical examples and timely relevance makes it worth reading.
November 23, 2025
An excellent follow-up to the author's work on WWII. Takes the lessons from that conflict about the key importance of force regeneration and generalises them effectively. Of particular importance to any realistic analysis of the power in our present day world.
January 21, 2026
Excellent book
While the subject is timeless and covered a great period of conflict. I still learned things I didn't know and new ways of looking at situations that I hadn't considered. Which is always the mark of an excellent book. I highly recommend this work.
While the subject is timeless and covered a great period of conflict. I still learned things I didn't know and new ways of looking at situations that I hadn't considered. Which is always the mark of an excellent book. I highly recommend this work.
December 14, 2025
Too much jumping from a subject to another. Also, what is the deal with em dashes? Felt like AI written content.
February 1, 2026
excellent.
February 7, 2026
Discusses WW1/WW2 almost exclusively (absolutely does touch on Soviets in Afghanistan and US in Vietnam).
Vietnam is a good case study in what the NV do on this list to win? Sure they had an amount of Soviet backing, but why no focus on the leadership or will of the people. Only discussed in the sense that the US sucked itself into a non willing partnership and how it lost.
Phillips makes great arguments to support his hypothesis; well researched and explained. After reading I feel like it's very difficult to argue against it. This is the sum of all War and Power knowledge!
It focuses, weakly I would say, on a future war between China and the US that was perhaps added as a request. It's a whole lot of crystal balling and it's hard to know if it's too conservative - I think so, but that might be a lack of subject expertise rather than knowledgeable conclusion. Geopolitics is changing so fast in 2025 it's hard to put anything to paper and be confident - the book already has an epilogue updating it at point of printing!
Overall I learned a lot about WW1, WW2 and the specific concepts discussed; and it was enjoyable. I feel confident speaking to the concepts and promoting the idea Philips is discussing.
Vietnam is a good case study in what the NV do on this list to win? Sure they had an amount of Soviet backing, but why no focus on the leadership or will of the people. Only discussed in the sense that the US sucked itself into a non willing partnership and how it lost.
Phillips makes great arguments to support his hypothesis; well researched and explained. After reading I feel like it's very difficult to argue against it. This is the sum of all War and Power knowledge!
It focuses, weakly I would say, on a future war between China and the US that was perhaps added as a request. It's a whole lot of crystal balling and it's hard to know if it's too conservative - I think so, but that might be a lack of subject expertise rather than knowledgeable conclusion. Geopolitics is changing so fast in 2025 it's hard to put anything to paper and be confident - the book already has an epilogue updating it at point of printing!
Overall I learned a lot about WW1, WW2 and the specific concepts discussed; and it was enjoyable. I feel confident speaking to the concepts and promoting the idea Philips is discussing.
Displaying 1 - 14 of 14 reviews