Ancient Greek Realpolitik? “The strong do what they can and the weak suffer what they must.”

From Thucydides's Melian Dialogue:

"You know as well as we do that right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must."

Athenians to the Melians, History of The Peloponnesian War (5th century BC)