Political violence has existed as long as politics. From both the left and the right, violence against political enemies has been a feature, not a bug, of radical political movements.
Vladimir Lenin developed a 鈥渟cience of terror鈥, in which violence was essential to overthrow the state. In Mein Kampf, Adolf Hitler declared: 鈥淭he very first essential for success is a perpetually constant and regular employment of violence.鈥 And Benito Mussolini declared political violence a necessary tool both in his early days as a socialist and after his conversion to fascism. Radicals demonise their enemies and insist on responding with violence justified by any means.