How much force can police use?
The first answer to that question probably ought to be another question, “Under what circumstances?”
For example, if someone’s passively resisting – just goes limp, doesn’t fight back – should a police officer whip out his issue sidearm and kill them? Perhaps if the officer is a member of the Chicago Police Department (where apparently officers can get away with anything) but in a normal police department, such behavior will get you fired and criminally charged.
Is this okay?