The primary factor that is pushing us toward civil war is undiluted democracy.
Pure democracy translates into 'who gets thrown off of the island today', 'who should we silence now', 'who should be robbed of all that they possess - for social justice'.
Pure majority rule is equal to mob rule,
It's the most dangerous and addictive drug... .
Yes, 'tyranny of the majority', as John Adams put it. The US Constitution is largely written to avoid that very problem, which is inherent in parliamentary democracies.
But I don't see why you think it is suddenly an issue. There are several events in US history that expanded democracy:
1. 15th Amendment - gave former slaves the right to vote
2. 19th Amendment - gave women the right to vote
3. Voting Rights Act of 1965 (and similar acts from 1957 and 1960) - blocked the former states of the confederacy (or any state) from preventing blacks from exercising their franchise to vote (poll taxes, 'literacy' tests, voter intimidation, etc., were common in the former Confederacy from 1877-1965).
I would argue that these were all legitimate (and vital) expansions of voting rights, and proper extensions of democratic rule in the US. (although I am sure there are still plenty of people who would prefer the Voting Rights Act of 1965 was never passed, and maybe a few on the 19th Amendment).
There are still three independent branches of government and still an electoral college, so as far as I can see, the institutions to prevent tyranny of the majority are still in place. What makes you think this has changed?