If you have the power to put a stop to subjugation, yet look the other way while it happens, then you have done it yourselves, - Thucydides

...when these matters are discussed by practical people, the standard of justice depends on the equality of power to compel...

Melians: And how, pray, could it turn out as good for us to serve as for you to rule?

Athenians: Because you would have the advantage of submitting before suffering the worst, and we should gain by not destroying you.

Melians: So that you would not consent to our being neutral, friends instead of enemies, but allies of neither side.

Athenians: No; for your hostility cannot so much hurt us as your friendship will be an argument to our subjects of our weakness, and your enmity of our power.

Melians: Is that your subjects' idea of equity, to put those who have nothing to do with you in the same category with peoples that are most of them your own colonists, and some conquered rebels?

Athenians: As far as right goes they think one has as much of it as the other, and that if any maintain their independence it is because they are strong, and that if we do not molest them it is because we are afraid; so that besides extending our empire we should gain in security by your subjection; the fact that you are islanders and weaker than others rendering it all the more important that you should not succeed in baffling the masters of the sea.

if one follows one’s self-interest one wants to be safe, whereas the path of justice and honour involves one in danger.