Atomism and Nationalism

According to Atomism, Relations are External, i. e. an Atom exists independently of any Relation with other Atoms into which it might enter.  So, any Polity that needs trade with another is not an Atom.  Now, whether or not there is or has been a Polity that is self-sufficient is uncertain, or, conversely, one is not to be found among the known Polities of past and present.  Nevertheless, the Nation has always been treated as an Atom, not only in the major works of Modern Political Philosophy, but, in common practice, as well, as routine and pervasive Patriotism in everyday affairs regularly expresses.  In either case, the implicit Atomism is inadequate, and is a fiction that is becoming increasingly difficult to maintain.