Those who speak of civil war and splitting the nation are out of touch with just how political demographics look in today's U.S.A.
I was living in Missouri when the concealed carry law was first defeated. Every Missouri county approved it, except those in KC, St. Louis, and Columbia (a college town). Similar results are seen across the nation on similar issues. The large population centers---New York, Philadelphia, L.A.---are politically very different from the rest of their states. Today, politics and culture are split very much along population density lines, with the masses of city dwellers outvoting everyone else. The only north/south, east/west split is related to population density. Should the thin veneer of civilization begin to dissolve, these high-density populations will be the first to suffer the effects. The great threat to the rest of the nation comes when life becomes untenable in the cities, and mass exodus ensues. Law-abiding citizens will feel justified in acquiring the necessities of life in whatever way they can, and the hard-core lawless will be absolutely unrestrained.
In a worst-case scenario, post-election rioting, whether celebratory or angry, could get out of control. Left unchecked, widespread unrest could start a general meltdown of law and order, with big-city politicians incapable of ordering the harsh measures that would be necessary to halt the lawlessness. Governers, stripped of National Guard forces, would be unable to step in. Putting regular military forces into the fray would set a terrible precedent, and further inflame the political situation.
I sincerely hope that none of this comes to pass. I hope we see a resilience in the American people that can handle unsatifactory political outcomes. But I know how little it takes to tun a crowd into a mob, and I will be watching carefully.