Political violence tore America apart in the 1850s. Today, this Yale historian says we’re ‘on the edge’

This is how things are going in America right now: One week before arguably the most important and most fraught midterm election in decades, the book that best captures the zeitgeist is a tome about U.S. congressmen and senators staging rolling fistfights and brawls across the disgusting tobacco-spit-stained carpet of the Capitol, pulling knives or the occasional pistol on each other, or clobbering a colleague with a cane to within an inch of his life.