We like to think wars are won on battlefields. The decisive charge, the brilliant maneuver, the general who outsmarts his opponent—these are the images that dominate our understanding of conflict. But what if we’ve been looking at the wrong level of analysis entirely?

Phillips Payson O’Brien’s War and Power offers a radically different lens for understanding modern warfare. His central claim is provocative but well-supported: great-power wars are not decided by tactical brilliance or even operational superiority. They are won by whoever can better sustain the systems that enable war—industry, finance, logistics, energy, shipping, and the global networks that connect them.

World War II: A Case Study in Systemic Victory

O’Brien’s most compelling evidence comes from his reinterpretation of World War II. The conventional narrative focuses on turning-point battles: Stalingrad, Midway, D-Day. But O’Brien argues these battles were symptoms, not causes, of Allied victory.

Consider the contrast:

Germany and Japan fought wars centered on destroying enemy armies and seizing territory. They excelled at this. The Wehrmacht’s early campaigns were masterpieces of operational art. Japan’s conquests across the Pacific were breathtaking in speed and scope. They won spectacular battles.

But they lost the war.

Why? Because the Allies fought a different kind of war entirely. Rather than focusing primarily on destroying Axis armies, the Allies systematically strangled the enemy’s ability to function as modern states at war. They sank merchant shipping, bombed industrial production, denied access to oil and capital markets, and economically isolated the Axis powers.

The decisive advantage wasn’t American soldiers being better trained than German ones. It was that America could produce ships faster than Germany could sink them, planes faster than they could shoot them down, and tanks faster than they could destroy them. And crucially, America could do this while maintaining a coalition that gave them access to British intelligence, Soviet manpower, and a global network of bases and supply lines.

Victory didn’t follow from tactical brilliance on the battlefield. It followed from systemic dominance.

Extension One: War Is Coalition Warfare by Default

This leads to O’Brien’s first major extension of the framework: in the modern era, great-power war is coalition warfare by default.

Modern war is simply too complex, too expensive, and too system-dependent for any major power to fight alone. The decisive Allied advantage in WWII wasn’t just American industrial might in isolation—it was the creation of a sustainable, willing alliance that integrated:

  • Industrial capacity across multiple states
  • Financial systems and credit mechanisms
  • Shipping and logistics networks spanning the globe
  • Technology sharing and coordinated R&D
  • Political legitimacy and shared purpose

The Axis alliances, by contrast, were brittle and poorly integrated. Germany, Japan, and Italy didn’t share systems—they merely coordinated armies. There was minimal industrial integration, limited technology transfer, and virtually no shared financial infrastructure. They were transactional partnerships held together by immediate military necessity, not deep systemic integration.

The Allied coalition, on the other hand, functioned as a single war-fighting organism.

O’Brien’s lesson for contemporary geopolitics is uncomfortably clear: future wars among great powers will be won by those who can build and maintain alliances of states that choose to participate, share burdens, and integrate systems over time. Coerced partners, transactional alignments, and ad-hoc coalitions collapse under sustained stress.

This fundamentally reframes what geopolitical competition looks like. The contest is not just “Who has better weapons?” but “Who can align more of the world’s productive and connective capacity to their side?”

Ports, semiconductor fabs, undersea data cables, shipyards, and financial infrastructure located inside allied states are not merely “civilian” assets. In O’Brien’s framework, they are core elements of war power. The global distribution of these capabilities matters as much as—perhaps more than—the number of tanks or missiles any single nation possesses.

Extension Two: War Is a Whole-of-Society Enterprise

O’Brien’s second major extension restores an uncomfortable truth that industrial-age warfare made unavoidable: war is not primarily a military affair. It is a societal one.

Modern wars among great powers require:

  • Long-term industrial mobilization
  • Public acceptance of economic sacrifice
  • Political cohesion under sustained stress
  • Societal tolerance for disruption and loss

A state whose population is unwilling to endure costs cannot sustain the systems of war, regardless of how advanced its weapons systems are. The “center of gravity” isn’t just factories and naval bases—it’s public belief that the war is necessary and legitimate.

World War II illustrates this clearly. Allied societies accepted rationing, bombing of their cities, mass conscription, and years of economic hardship. There was genuine, sustained public consent for the war effort.

Axis societies, by contrast, were brittle. Propaganda substituted for consent. Military success masked an increasingly fragile social contract. When the military tide turned, these societies cracked.

What This Means for the 21st Century

For our current era, O’Brien’s framework is both clarifying and uncomfortable.

Wars among great powers in the 21st century will be long, economically disruptive, and systemically invasive. They won’t be contained to distant battlefields. They will touch energy prices, consumer goods availability, employment, and information flows. They will require sustained sacrifice.

Victory will belong to societies that can:

  • Clearly explain why the struggle matters
  • Sustain public consent over years, not months
  • Align economic policy with strategic objectives
  • Treat resilience as a civic virtue, not a temporary wartime measure

Perhaps most provocatively, O’Brien suggests that a modern great-power war is already underway—in domains like semiconductors, shipping routes, financial systems, and energy infrastructure. Export controls on advanced chips, financial sanctions, supply-chain realignment, industrial policy aimed at reshoring critical production—these aren’t preludes to conflict. They are the battlefield.

Kinetic military conflict, should it come, would merely accelerate dynamics already in motion.

The Strategic Shift

The shift O’Brien demands is profound. We must stop thinking primarily in terms of winning battles and start thinking in terms of owning the conditions that make war sustainable.

This means:

  • Building alliances based on deep systemic integration, not just military coordination
  • Investing in resilient, distributed supply chains for critical goods
  • Maintaining industrial capacity even when it’s economically inefficient in peacetime
  • Cultivating societal resilience and public understanding of what great-power competition entails
  • Treating ports, cables, fabs, and financial infrastructure as strategic assets, not just economic ones

In a world of systemic warfare, the traditional distinction between “economic” and “military” power collapses. The capacity to produce, move, pay for, and coordinate complex operations at scale is military power.

The question facing any great power today is not “Can we win the next war?” but rather “Can we build and sustain the alliances, industrial base, and social cohesion necessary to prevail in a systemic contest that may last for years or decades?”

O’Brien’s answer suggests that traditional military metrics—divisions, aircraft, ships—are necessary but not sufficient. The real measure of power is whether you can keep your society producing, your allies committed, and your systems functioning when everything is under maximum stress.

That’s a very different kind of preparedness than we’re used to thinking about. And it may be the only kind that matters.