Thucydides Was Not a Realist — He Was a Cartographer of Self-Deception

Thucydides is having a moment in the headlines — Canadian Prime Minister Mark Carney quoted him at Davos earlier this year, invoking the ancient historian's most famous line to critique the Trump administration's foreign policy posture. The line — 'The strong do what they can, and the weak suffer what they must' — has become shorthand for hard-nosed realism in world affairs. But that reading fundamentally misrepresents what Thucydides was actually doing. His History of the Peloponnesian War, which chronicles the 27-year conflict between Athens and Sparta from 431 to 404 BCE, is less a manifesto for power politics than a forensic dissection of how powerful and powerless actors alike deceive themselves into catastrophe.

The famous line itself is commonly mistranslated. The Greek verb used — συγχωρέω — means something closer to 'yield' than 'suffer,' making the Athenians' statement to the Melians less a brutalist credo and more an invitation to negotiate without pretense. The Melians, an ostensibly neutral island city, rejected Athenian demands for tribute and alliance, banking instead on divine favor and Spartan military rescue. Both assumptions proved disastrously wrong. The Spartans never came; the Athenians destroyed Melos, killing all the men and enslaving the women and children. Within six months, Athens launched its catastrophic Sicilian expedition — a force of roughly 40,000 men obliterated. Many ancient and modern readers view the Sicilian disaster as a form of historical karma for Melos.

Thucydides, however, refuses to moralize in his own voice. He barely editorializes at all — Thomas Hobbes, who first translated him from Greek to English, noted that Thucydides 'does not digress to read a lecture, moral or political, upon his own text.' That authorial silence has made the History a Rorschach test, with realists, liberals, and imperialists all finding their assumptions confirmed. But the deeper argument Thucydides makes is about self-deception as a perennial feature of political life — not just for the weak who overestimate justice's protective power, but for the strong who mistake brutality for wisdom.

Sparta is the book's most instructive case. The Spartans went to war against Athens proclaiming themselves 'liberators of Hellas,' denouncing Athenian empire as slavery. But Thucydides is explicit: Sparta voted for war primarily out of fear of Athenian growth, not out of principled commitment to Greek freedom. Meanwhile, Sparta committed some of the war's worst atrocities — massacring 200 Plataeans to please their ally Thebes, annihilating the city of Hysiae, and most chillingly, selecting 2,000 of their own helot slaves who had fought bravely for Sparta, promising them freedom, then quietly killing every one of them. No one ever learned how. The Spartans' self-deception was not cynicism but something stranger: a passion for justice that had curdled into a pathological appetite for punishment, applied even to their most loyal subjects.

Thucydides wrote the History expecting it to be useful for all time precisely because human psychology — the mix of fear, honor, and self-interest that drives individuals and cities alike — does not change. His work is not a playbook for would-be empire builders or a lament for the powerless. It is a warning that the most dangerous delusions belong not to the obviously weak or obviously wicked, but to those — strong or just — who believe their own narratives about why they act as they do.