Historically Thinking

Historically Thinking


War and Power: Phillips Payson O’Brien on Who Wins Wars and Why

November 05, 2025

For at least two centuries, ideas of international relations and grand strategy have been premised on the notion of “great powers.” These were mighty states uniquely able to exert their influence through overwhelming military force. In the words of friend of the podcast Leopold von Ranke, a great power was one who could “maintain itself against all others, even when they are united”—but my guest, Phillips Payson O’Brien, argues that this definition is ahistorical nonsense.


Indeed “great power” he says, has always been a tautology. Nor has it been helpful or accurate to focus who has the biggest armies. And dreaming of decisive battle has blinded us to what truly determines victory: the capacity to mobilize and sustain industrial power, logistics, technology, and global reach.


In his new book War and Power: Who Wins Wars and Why, O’Brien dismantles some popular myths of military and diplomatic history and replaces them with a far more dynamic picture—one that redefines how states fight, how they win, and how we should understand power itself in the twenty-first century.


For this episode's show notes, and other resources, go to the Historically Thinking Substack


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