The police are specialists in coercive force. Their distinguishing characteristic is the combination of surveillance and violence to make people do what people with power want them to do. That usually gets described in terms enforcing the law, but what I found in my research is that the real distribution of power is a much better indicator of how the police will act in any given situation. On the whole, they behave in ways that serve the interests of the powerful at the expense of the rest of us.