Reading this, I realize that almost everything is a case for localism, since we now have nuclear weapons and international instantaneous communications that mean trying to invade a small country is much less reasonable (unless you are Russia).
I mean, that is (in part) why the Greek model failed. Small countries are vulnerable to conquest. But today that is not much of a problem, so I hope the natural social pressure to minimize can overcome the entrenched imperialistic powers that hold a lot of the larger nations together. It just makes more sense to me to, say, have 50 countries and a EU in the US instead of one massively overbearing federal that has authority over a land area competing with continental Europe.
Norway's success is a strong case for localism.