Athens lost the Civil War the instant that it ceded its moral superiority over the slavers. This is how you produce Thucydides in a culture that was worthy of Pericles. This is how you become dominated by Philip II when your culture was worthy of being liberated by Socrates.
"It is a law of nature for the greater to dominate over the lesser"
THEN DO IT
BECOME GREATER, NOBLER, FREER THAN YOUR RIVALS