In his reflections on the city-state, Jamie Barlett explains that:
nation-states are nothing but agreed-upon myths: we give up certain freedoms in order to secure others. But if that transaction no longer works, and we stop agreeing on the myth, it ceases to have power over us. (Source)
This is similar to the ideas of Benedict Anderson and the notion of 'imagined communities'. It is also interesting to consider this idea in regards to Edward Said's discussion of 'coexistence with the preservation of difference'.