" The erosion of basic norms expanded the zone of acceptable political action. Several years before shots were fired at Fort Sumter, partisan violence pervaded Congress. Yale historian Joanne Freeman estimates that there were 125 incidents of violence—including stabbings, canings, and the pulling of pistols—on the floor of the U.S. House and Senate between 1830 and 1860. "

― Steven Levitsky , How Democracies Die: What History Reveals About Our Future