They've been trained to believe that America's cops go into a combat zone when they stop cars for broken taillights. They, like police, have been sold an action movie. They've been told that the No. 1 goal of all police officers is to protect their own life above all others, and the minute they feel threatened, they can kill with impunity.

That most cops don't do this (shoot and kill) is immaterial. This mindset is so pervasive in this country that in South Carolina, a cop shot a guy in the back while he was running away. That cop didn't go into his day thinking "Hey, I'm going to kill someone today and screw up my career." That shooting was the result of implicit racism and corrupt thinking that a cop's job is to not die. If you go into a job thinking "I may die today," it becomes self-fulfilling. You're looking for that moment when you might die, and thinking of how to defend against that with the gun you've been given. So when a bad cop hears Castile say he has a gun, he goes to his trained reaction. See gun, shoot to kill.

This is why cops should not carry guns with them in most cases. The guns should be in the car, and you should have to punch in a code (which corresponds to an official reason) to get the gun. There's no reason to carry a gun to a brake-light traffic stop. It's the legal equivalent of having your shoe untied.