I think that the article by Lew Rockwell that I just referenced is really worth reading:
In Mises's view, in order to maintain peace and free trade, large nation-states had to become small nations based on the will of the people. Otherwise, he said, they would be centers of civil strife, where wars of some against some would perpetuate themselves. He also believed that all groups needed the right to separate from the state and form their own states. This was the only way that democracy could be implemented.
My own thinking has evolved to this point of view and not just for states as large as the US. The same argument can be made about the UK. Proper devolution coupled with fewer restrictions on the movement of people and ideas. This naturally leads to an answer to immigration problems:
Or we can choose the direction of liberty, which requires devolution, decentralization, and the elimination of tax-paid privileges for immigrants. Never before has the choice for the right and true been so crucial.
This doesn't affect each mans choice about where to spend his own money in the furtherance of the world society in which he wishes to live. In fact it gives him more freedom to exercise his judgement and to escape the unwise judgements of others.
In my vision we end up in a situation where good societies really do evolve because they are fitter. [Curiouser and Curiouser!]