Americans Increasingly Believe Violence is Justified if the Other Side Wins

At the presidential debate this week, the Republican candidate voiced his concern about political violence—left-wing political violence. And the Democratic candidate likewise voiced concern about political violence—right-wing political violence.

They were both right.

Like a growing number of prominent American leaders and scholars, we are increasingly anxious that this country is headed toward the worst post-election crisis in a century and a half. Our biggest concern is that a disputed presidential election—especially if there are close contests in a few swing states, or if one candidate denounces the legitimacy of...