A second civil war in the US would last for decades and possibly centuries................
Decades only in the same sense that our first civil war lasted that long with post-war friction. The actual widespread shooting would last from 5-8 years. Millions of decent people will die in that war, along with tens of millions of socialists and their allies/sympathizers. I hope we can avoid it, but that civil war is far more likely now than it seemed just a year ago. It could start as early as the window between Election Day and Inauguration Day.
No civil war has lasted centuries that I know of.
“The Karen Conflict is the longest civil war in the world, having had started in 1949 and is still ongoing. The Karen Conflict involves the Karen people, one of the largest ethnic groups in Southeast Asia, who have been fighting since ages long past for a separate Karen nation of their own in Myanmar (Burma).”