The Papal States offer a helpful case study in understanding the transformation of Europe in the nineteenth century. Unfortunately, Kertzer's study on the topic is couched in faulty notions of enlightenment and medievalism.
Ludwig von Mises understood that locally based governance "follows necessarily from the principle of the rights of man.” And it's why Rothbard supported secession and local governance right down to the most local level possible.
If you were to browse the economics sections of bookstores here in my home city, Dublin, you would find a wide variety of books by anticapitalist celebrity economists. Books by free market economists? Not so much.
The Nuremberg prosecutors wanted to indict the Nazis on trial for crimes, but at the same time they wanted to preserve the dogma that the modern European nation-state is the culmination of moral progress. This created a conundrum.
Staten Island once voted 2-to-1 to leave New York City. The Manhattan overlords ignored the vote. But Staten Island would be better off as a separate city, and the same holds true for Brooklyn and Queens.