Aurora borealis lights up the night sky over residential houses in Nuuk, Greenland, on Friday, January 23. Jonathan Nackstrand/AFP/Getty Images

Analysis by Brett H. McGurk, Jan. 25, 2026 CNN

In 416 BC, the city-state of Athens was in a prolonged conflict with Sparta, its archrival. For years, Athens had enjoyed comparative advantage over Sparta, particularly alliances and mutual defense pacts with smaller city-states known as the Delian League. By 416 BC, the Delian League had been in place for nearly 70 years, roughly the same as NATO, the modern equivalent of a prolonged and successful mutual defense alliance.

That was also the year that Athens came to view the Mediterranean island of Melos as vital for its strategic position. Melos had no military of its own, but it sat geographically at the intersection of maritime routes that helped both protect and project Athenian power. The island had long claimed neutrality, but for Athens, that would no longer suffice.

When an Athenian delegation demanded that Melos become a part of Athens, the Melians refused and appealed to Athenian traditions of logic and justice to work out a compromise. The Athenians responded with a famous line about power: “You know as well as we do that right, as the world goes, is only a question between equals in power — while the strong do what they can, and the weak suffer what they must.”