"Where the people fear the government, you have tyranny. Where the government fears the people, you have liberty." - John Basil Barnhill, 1914
We have had a terrible spate of killings by police, mainly of people of color, and a terrible spate of killings of police as well. While much of the discussion has centered around race and policing, there's another aspect that also deserves attention.
The police are acting in the name of our government. We pay their salaries to "serve and protect" all of us, regardless of color. When the police go beyond that to assault or to kill anybody, regardless of color, they are violating their function. In this sense a murder or assault committed by a police officer is even more serious, even more damaging to the social fabric, than a murder or assault committed by someone else.
This is not a problem that is to be solved by diversifying police departments, although that's a worthy thing to do. If a person is wrongly killed by a police officer, the race of the officer doesn't matter. Nor is it to be solved by "training," consisting of exposing police officers to boring lectures. Police have to be held to a higher standard because they are sanctioned by the state to use force.
There is, in addition, a racial aspect in some of the recent, highly publicized killings. Our history of slavery, white supremacy, and Jim Crow segregation still reverberates, and must be part of our national conversation. But I think it would be a mistake to view such killings solely as a racial matter. Whenever there is a police killing of a civilian we must all be concerned, regardless of the race of the police officer and the race of the civilian.