The police in Kern County, California--population 875000--killed 14 people in 2015. That's almost three times as many as were killed that year by police in Germany and the UK combined--total population 145,000,000.
Police in my home town, Albuquerque, New Mexico, killed 28 people between January, 2010 and July, 2014. That's more than t wice as many as police killed in Germany during the same time period. Albuquerque has a population of 556,000. Germany has a population of 80,620,000. That means that the citizens of Albuquerque were 300 times more likely to die at the hands of police than the citizens of Germany.
Clearly, there's something different about how US police are trained, governed and see their relationship to the rest of us, compared to police in other countries. You can read a thoughtful expert commentary by criminal justice professor Paul Hirschfield at this URL.
Hirschfield identifies a variety of contributing factors, but emphasizes that police in other developed countries receive significantly more training than in the US, including much more training in how to manage critical situations--for example dealing with agitated or mentally ill people--without resorting to lethal force.
He also focuses on national and international standards which typically permit lethal force only as a last resort and when absolutely necessary. In the US, standards are far more lax. Most states empower police to use lethal force if they reasonably believe they or someone else is at risk of imminent or grave harm. In the vast majority of cases, review boards, district attorneys, judges and juries give police officers enormous leeway concerning the circumstances or behavior that could have justified their perception of risk.
It's in large part that very low bar to the use of lethal force in the US that leads to the kinds of killings that outrage us all too frequently. Both training and the legal standards for the use of lethal force urgently need to be improved if the police are to be seen not as soldiers on the front line of a war, but as the face of justice in our communities and on the streets.
(Article changed on January 7, 2017 at 15:19)