The dotted line from before the Oklahoma City bombing to the anti-mask protests and the Gretchen Whitmer kidnapping plot to the Jan. 6th Capitol attack. Why does America have an  apparent inclination toward violent extremism? How are populism,  grievance politics and nationalism  playing into that inclination across the political spectrum? And what can law enforcement, national  security experts and elected officials do to turn  down the temperature? Or, is it too late?