A leading political scientist examines the dramatic rise in violent extremism around the globe and sounds the alarm on the increasing likelihood of a second civil war in the United States“Like those who spoke up clearly about the dangers of global warming decades ago, Walter delivers a grave message that we ignore at our peril.”—David Remnick, The New YorkerPolitical violence rips apart several towns in southwest Texas. A far-right militia plots to kidnap the governor of Mich