The fear behind empires.

Why the Thucydides trap Is back in the conversation between Xi Jinping and Donald Trump

By Adelio Debenedetti, author of The Naacal Protocol – Code 211

Bust of the ancient Greek historian Thucydides, whose analysis of fear and power inspired the modern concept known as the Thucydides Trap.

Empires don't like to admit they're scared. But fear, more than ambition, has started most of the wars that mattered. Twenty-four centuries ago, the historian Thucydides watched Athens and Sparta stumble into a war neither side really wanted, and came away with a blunt diagnosis: it was the rise of Athens, and the fear that rise put into Sparta, that made the fighting almost impossible to avoid. Historians later gave that pattern a name — the Thucydides Trap. It isn't a law of physics and it isn't a prophecy. It's a warning about what tends to happen when a power that's used to running the show starts to suspect someone else is catching up. Fear behind empires

Chinese President Xi Jinping and U.S. President Donald Trump during a bilateral meeting, symbolizing the strategic competition between an established and a rising global power.

That warning keeps resurfacing in Washington and Beijing. It's shown up in think-tank memos, in closed-door briefings, and lately in the running commentary around what Xi Jinping and Donald Trump actually say to each other when the cameras are off. The reason it keeps coming back is simple: both capitals know the real danger isn't a surprise attack. It's a miscalculation — one side reading the other's intentions wrong. The U.S. still fields the most powerful military on the planet. China keeps closing the gap in money, technology, and reach. Neither government is angling for a shooting war. But both are quietly hedging against the chance that the rivalry hardens into something closer to one. That's the part where Thucydides earns his keep. The question that matters isn't whether Beijing actually intends to push Washington off its perch. It's whether enough people inside the American national security establishment have started to believe it might. History is fairly consistent on this point: countries react less to what a rival is doing than to what they're afraid it might do next. That gap between fact and fear is doing a lot of the work in shaping this century.

Map of the GIUK Gap, the strategic maritime corridor connecting Greenland, Iceland, and the United Kingdom, central to NATO's North Atlantic deterrence architecture.

And the rivalry itself has long since spilled past trade wars and diplomatic sniping. It's playing out in chip factories, in AI labs, in the mines that produce cobalt and rare earths, in shipping lanes, undersea cables, and satellite constellations. Taiwan gets the headlines, understandably. But headlines rarely tell the whole story. The quieter, harder-edged competition is happening across a web of corridors and infrastructure that almost nobody outside a handful of specialists pays attention to. Call it the Grey Zone — the space between peace and open war, where economic pressure, export controls, intelligence work, and military posturing all substitute for actual combat. Washington and Beijing are already fighting there, just without the tanks. Here's the thing about great powers: they spend the most money not where they expect to fight, but where they're afraid of being caught flat-footed. That's why chokepoints keep mattering long after the strategic logic behind them seems to belong to another era. Take the GIUK Gap — the stretch of ocean between Greenland, Iceland, and the U.K. It's been a NATO listening post for submarine traffic since the Cold War, and it still is. On the surface, a strip of the North Atlantic has nothing to do with the U.S.-China rivalry. Underneath, it's the same instinct at work.

Great powers want to see clearly. They want warning time. Above all, they want some insurance against being blindsided. Sparta wanted that. So does every capital trying to navigate a world that's gotten a lot less predictable. The real lesson of the Thucydides Trap was never that war is inevitable. It's that fear gets louder every time the balance of power shifts — and that the shift itself, not any single decision, is what puts everyone on edge. Wars don't usually start on a battlefield. They start earlier, in the calculations, the infrastructure, and the sense that the ground is moving. That's exactly where the Grey Zones of this century are taking shape.

This article is part of the Grey Zones Archive editorial project, a long-form analysis series focused on Arctic geopolitics, strategic chokepoints, cognitive warfare, hybrid conflict, dual-use infrastructure and the evolving balance of power in the 21st century. The analyses published on The Naacal Protocol Blog  explore the increasingly blurred line between intelligence, strategic geography and contemporary geopolitical narratives, in continuity with the research-based universe of The Naacal Protocol – Code 211 by Adelio Debenedetti.