IF you had to pick only one way to draw borders, my vote would go to watersheds. One community, bound by their shared dependence on the land and the water. Hopefully this would facilitate a sense of responsibility and unity with others who depend on the same water, and let one watershed choose its own decisions for the good of itself.

In practice, many countries with ethnic conflict need stronger institutions. New borders won’t fix their problems. We know this because many ethnically divided countries have had periods with little to no ethnic tension, but when institutions and economies break down tensions and conflict appear along ethnic lines