This is not a fully developed thought, but I think the current Eurozone crisis shows the difficulty of trying to politically unify culturally diverse people groups.<p>I am not an economist or a political theorist, but I think that the Eurozone crisis proves that in trying to create the EU and gain some of the economic advantages that the United States has with a single currency (and other advantages as well, I know I am simplifying), the Eurozone founders didn't fully take into account the cultural issues that their creation would face. America, for various and sundry reasons easily traceable through its founding, is largely culturally monolithic (I realize this is a simplification, yes) and by and large, Americans in one geographic region of the country (for example, the Midwest, which didn't fly too high in the recent booms but is also not facing a bottom dropping out like other regions) do not strenuously question the need to 'bail out' other areas of the country through large federal spending. It happens in America, its just largely invisible and rarely widely debated along geographic lines (farm subsidies, bank bailouts, automaker bailouts, all can be argued to have a strong geographic context that largely gets ignored in America politics) because of the strong nationalistic component in America that the Eurozone lacks.<p>Smaller versions of this basic problem can be seen, manifested in different ways, all throughout Asia (Afghanistan, India, India/Pakistan, Laos, China) and Africa (Sudan/South Sudan, the DRC), and probably though South America too, but I am far less familiar with SA.