The attitude you describe has been the foundation of every nation's moral policy for thousands of years. Thucydides set it as follows in the Melian Dialogue, in

The attitude you describe has been the foundation of every nation's moral policy for thousands of years. Thucydides set it as follows in the Melian Dialogue, in which the Athenian and Melian ambassadors discuss the subjection of Melos: "We hope that you [Melians], instead of thinking to influence us by saying that you did not join the Lacedaemonians, although their colonists, or that you have done us no wrong, will aim at what is feasible, holding in view the real sentiments of us both; since 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." The Melians responded that the Athenians should nevertheless concern themselves with what was right because the Athenians themselves might be weak someday. This was the fate of the Melians, after they refused to surrender upfront and forced the Athenians to fight: [...] the Melians surrendered at discretion to the Athenians, who put to death all the grown men whom they took, and sold the women and children for slaves, and subsequently sent out five hundred colonists and inhabited the place themselves.