The bargain between the rulers and ruled is breaking down, with revolutionary implications. From the Zman at theburningplatform.com:
A popular fantasy among the more edgy conservatives is that one day, the Left will get the civil war they claim they want and then they’ll get it good and hard. In this fantasy, those gun-toting, constitution-loving conservatives will show Lefty why the right to bear arms was enshrined in the Constitution. It is a popular fantasy on-line, because revenge fantasies are fun and they provide relief for well-founded frustration. In reality, the great conflagration will never look like the fantasy.
Civil wars are when two sides in the ruling class cannot find a middle ground and refuse to give into the other side. The English Civil War, for example, was a fight between those elites who supported the King and those who supported Parliament. Sure, commoners were in the mix and rose in status, but it was largely a war between two factions within the elite. The same was true of the American Civil War. Slavery was the pretext, but it was largely an extension of the English Civil War.
Revolutions, on the other hand, are when a new elite overthrows the old elite, because the old system offers no way for the new elite to join the elite. The French Revolution is often framed as a peasant rebellion, but the Jacobins who led the revolt were educated and capable men, a new elite for a new age. The Bolshevik Revolution was similar, except there was competition for who would be the new elite. The communists won, so they got to name the revolution after themselves.