https://www.libertarianism.org/articles/insurrectionary-ideology-national-conservatism
This is a very interesting look at a dark time in America's history.
There's an unpleasant lesson in this dark history: reconstruction was insufficiently punitive, the northern occupation was of insufficient duration and the price of that neglect was paid in the blood of thousands of people murdered by those with confederate loyalties and by failing to adequately confront by means of force the ideology behind the confederacy, the United States still suffers from political echos of that time.
There's an unpleasant lesson to learn from this period of American history: bad ideas don't die naturally.
American history after the civil war should serve as a lesson of what happens when you settle for a 90% defeat of evil.