A History Lesson for Legitimate International Relations

This article, citing lessons learned about the limits of coercion from CBI's Workable Peace curriculum, was published by the Boston Globe's Ideas section on April 19, 2026. Read more about the Workable Peace curriculum here.

For years, I have watched ninth-graders learn a lesson that continues to elude some of the most powerful people in the world.

These students participate in a classroom role-play exercise based on one of history’s most famous diplomatic exchanges: the Melian Dialogue, recorded by Thucydides in his account of the Peloponnesian War. In 416 BC, Athenian envoys arrived at the small island of Melos with an ultimatum: submit or be destroyed. When the Melians protested, the Athenians cut them off. “The strong do what they can,” they said, “and the weak suffer what they must.”

The outcome: Athens “won” that conflict. Melos refused to submit and was conquered, its men killed, its women and children enslaved. In the very short term, it was a victory for Athens. Today, the logic of “the strong do what they can” seems to define how the world works. Great powers are ignoring the norms that once restrained them: Russia invaded Ukraine, and the United States arrested Venezuela’s leader and bombed Iran. The current administration’s approach to US foreign policy embodies the Athenian ethos, from a zero-sum approach to trade relationships to a willingness to take the country to war. As Canadian Prime Minister Mark Carney recently lamented at the World Economic Forum’s summit in Davos, “It seems that every day we’re reminded that we live in an era of great power rivalry, that the rules-based order is fading, that the strong can do what they can, and the weak must suffer what they must.”

That dictum is faulty, however. If aggressive world leaders insist on following it, everyone, including the strong, will suffer.

Those who admire the Athenians’ vision of strength seem to miss the fact that Thucydides didn’t record that exchange to celebrate it. It’s a prelude to catastrophe.

Within a few years, Athens’s enemies united against it. The empire Athens had built by force dissolved precisely because it had been built by force. Loyalty from its conquered coalition proved only as durable as the armed force holding it together. I have mediated environmental disputes, organizational conflicts, and complex multiparty negotiations, and I have seen how decisions dictated by the powerful are much less stable than agreements designed to meet the interests of all parties.

The students I observed almost always figured this out. In the role-play, some were Athenians, some Melians, and they were prompted to think beyond what they “can” or “must” do. Instead, they had to consider what would meet their core needs, uphold their values, and endure the test of time. Students routinely found compromises Athens never even considered — like reduced payment by the Melians or autonomy over some matters of governance. Those arrangements would have given Athens much of what it needed while giving Melos more reason to accept its rule. This is what mediation experts call the “mutual gains” approach to conflict resolution.

The students, in other words, learned the limits of coercion. By rejecting the moral case out of hand, Athens made its contempt for justice explicit and thereby handed every wavering city-state a common cause. Overtly illegitimate behavior reduces the cost of opposing the aggressor, makes coalition-building against it easier, and converts previously neutral parties into motivated adversaries. Legitimacy is not a constraint on power — it is a form of power. In their focus on demonstrating strength, the Athenians ignored the strategic importance of building legitimacy.

Mediators know that win-lose deals are almost always worse deals, especially in the long run. The pattern is consistent: One party’s interests are ignored and it is forced to comply with the aggressor’s demands, resentment accumulates, and the forced “agreement” holds only as long as the aggressor can maintain the pressure.

The mediators I work with share the conviction that achieving win-win deals on the world stage is possible. People practicing the dynamics of coercion and negotiation firsthand can learn to avoid the pitfalls of the raw, and usually short-lived, exercise of power.

The lesson from Thucydides, then, extends far beyond violent conflict. The ninth-graders in my classroom figured this out in an afternoon. The question is whether today’s strongmen will figure it out before the costs become irreversible.