It is true that in the end, the law and juries often protect the police who have acted properly. Don't kid yourself though, every cop knows - especially on the dem plantations like Chicago, Detroit, Fergeson etc- that the legitimate use of force can bring about riots and a screeching halt to his/her career almost instantly as the case is tried in the press. The furgeson cop? No longer a cop, right? Because he shot a guy who was twice his size who he had already fought off as he was trying to take his gun to kill him. And every cop in america knows what the lesson from fergeson is.
On the other hand, you can avoid all that by being muslim. A muslim officer summarily executed a white woman in her pajamas who had called 911 about a possible sexual assault in progress. We don't know much about what is going on with that case though and the community has remained calm because "it is important to not prejudge and to let the facts develop." Uh, huh. Not exactly the way it went in furgeson is it?