In the context of a discussion of Rousseau, Tzvetan Todorov neatly articulates one of the driving problems that extends from classical thought to contemporary political philosophy and ethics:
"Patriotism, then, has an inherent flaw. By preferring one segment of humanity over the rest, the citizen transgresses the fundamental principle of morality, that of universality; without saying so openly, he acknowledges that men are not equal... Now true morality, true justice, true virture presuppose universality, and thus equal rights. And yet in order to be able to exercise one's rights one must belong to a state, and thus be a citizen: there are no rights except within a juridical space underwritten by the establishment of a frontier separating inside from outside. The expressions 'rights of man' and 'world citizen' thus both entail internal contradictions. In order to have rights, one must be not a man but a citizen; yet - with apologies to Voltaire - only states have citizens, not the world. To be in favor of rights thus implies being on the side of the citizen, and yet the best principle of justice is that of universality."
- Todorov, On Human Diversity