Quite apart from the nuts-and-bolts macroeconomic reasons, the problem with the Scottish referendum is that nations are always infinitely sub-divisible. The Atom of the nation is the Individual but aside from that hard limit there’s no “rational optimal subdivision.” Where do you stop? Maybe extricate London—it could join Hong Kong and Singapore as a great city state—why shouldn’t one split off Cornwall, North Ireland, Wales? Why not have 64.1 million nations of one citizen each? As we observe in our own Congress, focusing on what divides and differentiates a nation does not build steel beams of strength but is the road to endless dysfunction.