You could look towards the EU today for some clues. You have 27 nations of quite different cultures and socioeconomic status with free movement of labor. I hav

You could look towards the EU today for some clues. You have 27 nations of quite different cultures and socioeconomic status with free movement of labor. I have found though that people like their country's customs and traditions a lot and are proud of the country their parents are from. However it's true that based on how strongly held some political beliefs are, some people would identify more with those from another country with the same political beliefs than those in their own country. Same with religion. It's important then to have things they share in common so they can get along in day-to-day life whilst disagreeing about other things. Diversity of thought and opinion is important, and I would argue thats its actually a good thing to have GPS coordinates determining a grouping, rather than letting people form groups with who they get along with best. What is the optimal grouping of countries and politics is an interesting question to ponder. Lots of lessons can be learned from history on this such as how borders of countries were drawn during British colonialism and also after each World War. The goal perhaps is to find the largest groups of people to put together whose political spectrums are not too wide that people can't get along with one another.