Like a well-formed man, there are limits to the size a state can have, so as not to be too large to be capable of being well governed, nor too small to be capable of preserving itself on its own.
Gist of Idea
A state must be big enough to preserve itself, but small enough to be governable
Jean-Jacques Rousseau (The Social Contract (tr Cress) , II.09)
Geneva was his model, and it is close to the size of a Greek polis. Presumably even Scotland would be thought ungovernable, never mind the United States. Luxembourg might be his ideal nowadays. Thousands of them!
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.167