Political violence is on the rise in America. What's driving it?

A U.S. flag and a candle sit on a step during a candlelight vigil and prayer event for Turning Point USA Founder Charlie Kirk on Sept. 10 in Seattle. Kirk was shot dead while speaking at Utah Valley University earlier in the day.

Before his apprehension, speculation about the identity and motivations of Charlie Kirk's killer filled the void. A increasingly familiar pattern of political violence is taking shape in America.

(Image credit: David Ryder)