In the end, the death toll will far exceed the 620,000 people who died in our first civil war.
I have seen estimates 3 to 5 times that number.
Most Americans (including me) are way too soft for anything to do with a real war.
They care way too much about their ice cream, Youtube, McDonalds, Kardashians, and Dancing with the Stars to ever take up arms over ANYTHING.
It just isn’t going to happen.
Let's look only at modern history, and only at Leftist takeovers. In most cases, they eliminate the segments of the population that weren't fervently enough behind them and/or refuse to cowtow to them after they take power. In Laos, it was 25% of the Hmong. In China, "In official study materials published in 1948, Mao envisaged that "one-tenth of the peasants" (or about 50,000,000) "would have to be destroyed" to facilitate agrarian reform.[137]" -Wikipedia. That's about 5% of China at that time.
A "low" figure of 5% in the US would equate to 15 million people today. Why make the same mistake as the Left, and presume that "this time it will be different"? (And... I wouldn't count on a "low" figure, since our side will NOT be disarmed.)
China: 40,000,000 (4%)
Soviet Union: 20,000,000 (18%)
North Korea: 3,000,000 (16%)
Ethiopia: 2,000,000 (4%)
Cambodia: 1,700,000 (13%)
Vietnam: 365,000 (after 1975)
Yugoslavia: 175,000
East Germany: 100,000
Romania: 100,000
North Vietnam: 50,000 (internally, 1954-75)
Cuba: 50,000
Mongolia: 35,000
Poland: 30,000
Bulgaria: 20,000
Czechoslovakia: 11,000
Albania: 5,000
Hungary: 5,000
NOTE: These counts are "only" from execution, labor camps, famine, and ethnic cleansing... it does not include internment, escape, or death from eventual decay.
The culture war in china in 1966 resulted in the deaths of thirty million people. It also retarded the country and it took fifty years to recover.