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The map above plots all the individual counties in the United States that the Clintons won by 20% or more in this Democratic primary. It closely resembles the migration path of settlers southward and westward circa 1830-1860. Fascinating, some very deep-rooted Americana at work here, but I won't go there. It'd be great to hear a demographer like Joel Garreau (who wrote The Nine Nations of North America) take a crack at an explanation.