For a man who's been dead for more than 2,000 years, the Ancient Athenian historian Thucydides is proving surprisingly relevant. He makes an appearance — though not one entirely based on facts — in the blockbuster Wonder Woman, and on Wednesday Politico reported that Graham Allison, the political scientist who wrote Destined for War: Can America and China Escape Thucydides's Trap?, recently briefed President Donald Trump's National Security Council on what the Peloponnesian War, fought between Athens and Sparta in the 5th century BC, could teach them about U.S.-China relations.
But, though Thucydides may be having a moment, theorists of international relations have always looked to his writings for guidance on approaching international conflicts.
He didn't always have all of the answers, however, and in fact, learned them the hard way. Thucydides was well-connected in Athenian society (he snagged an elite position as one of the ten stratēgoi, or military commanders, who were picked each year) but didn't prove himself a particularly adept military leader. During the war, the Spartan general Brasidas caught him and his fleet off-guard and was able to snatch up the strategically-important city of Amphipolis from under his nose. Thucydides was banished as a punishment so, during his 20 years in exile, which lasted until Sparta finally conquered Athens in 404 B.C., he had a lot of time to think about the meaning of war and write about the history he was living through.
His search for answers catalyzed by his military failures culminated in his renowned History of the Peloponnesian War.
In one of his most famous lines, Thucydides stated his belief that war between Athens and Sparta became inevitable as the former's power grew and thus inspired fear in the latter. This concept helped establish him as a father of the idea that nations act out of self-interest, as opposed to for the common good. The book is also famous for what's known as the "Melian Dialogue," a retelling of the Athenian invasion of Melos in 416 B.C., which pitted the Melians (who believed that right is on their side and some higher power will help them prevail in their just fight for political independence) against a stronger Athenian military, the representatives of which argued that Melos should just surrender rather than try to fight. It has become a textbook study of the tug-of-war between idealism and realism in military and political decision-making.
"In the History, Thucydides shows that power, if it is unrestrained by moderation and a sense of justice, brings about the uncontrolled desire for more power," according to the Stanford Encyclopedia of Philosophy. "There are no logical limits to the size of an empire. Drunk with the prospect of glory and gain, after conquering Melos, the Athenians engage in a war against Sicily. They pay no attention to the Melian argument that considerations of justice are useful to all in the longer run... And, as the Athenians overestimate their strength and in the end lose the war, their self-interested logic proves to be very shortsighted indeed."
National security adviser H.R. McMaster, who is one of the Trump administration's most notable Thucydides buffs, summed up the book's point even more simply in 2013: "War is human. People fight today for the same fundamental reasons the Greek historian Thucydides identified nearly 2,500 years ago: fear, honor and interest."