It is my belief that all great social discord is the conflict of urban vs. rural, and that all tyrannical systems consist of one of these portions of society forcibly dominating the other.  European Communism/Socialism was/is primarily urban, whereas Fascism and Nazism were predominantly rural for example. Monarchism and Feudalism were rural, where 19th century liberalism was urban. Rome itself was one city dominating their vast empire. East Asian and Latin American Communism are rural uprisings against corrupt urban elites. Even the Civil War was fought primarily upon these lines, albeit with the midwestern proto-libertarian smallholders joining up with the Eastern Urban abolitionists in the early Republican party.

The American polity, with the exception of the Reconstruction period, has been held in majority by rural voters. The Constitution was specifically constructed to give a slightly disproportionate weight to less populated (i.e. rural) states as a bulwark against tyranny of urban elites.

This is the first time in American history where metropolitan area dwellers, urban and suburban, are the majority in this country, and we have reached the point where one political party is almost wholly urban, and the other almost wholly rural.

I do not believe this situation bodes well for the American Civilization in the long term

Agreed that urban vs rural will be a big divide going forward.

But also consider the men/women divide. If only men voted in 2012:

Or consider if only white people voted in 2012: