If there is a silver lining in such a tragic story, it is about policing. Among the most compelling witnesses in the case were police officials. What had to have impressed the jury was how far Chauvin strayed from standard detention procedures. Police are trained that, if they must use a prone restraint, they are to roll the suspect onto his side as soon as he is secured — and especially if he has stopped resisting — in order to facilitate breathing. American cops also go by the credo, “In my custody, in my care.” No matter how serious the crime, no matter how loathsome the suspect, they are responsible for the wellbeing of the people they detain. If a detainee falls ill, they are duty-bound to administer care — and trained to do so as “first responders.” If a detainee loses his pulse, they are trained to begin CPR immediately. Chauvin did none of these things. As prosecutors said, “He wouldn’t let up, and he wouldn’t let up.” The police witnesses expressed a healthy disdain for that. They know nothing makes a good cop’s job harder than a bad cop.