In most of the liberal discussions of the recent police killings of unarmed black men, there is an underlying assumption that the police are supposed to protect and serve the population. That is, after all, what they were created to do.

If only the normal, decent relations between the police and the community could be re-established, this problem could be resolved. Poor people in general are more likely to be the victims of crime than anyone else, this reasoning goes, and in that way, they are in more need than anyone else of police protection. Maybe there are a few bad apples, but if only the police weren’t so racist, or didn’t carry out policies like stop-and-frisk, or weren’t so afraid of black people, or shot fewer unarmed men, they could function as a useful service that we all need.

This liberal way of viewing the problem rests on a misunderstanding of the origins of the police and what they were created to do.