American police departments were founded in the early 19th Century not to control crime but to combat civil dissent, which took the form of riots. Since then, relationships between police and the communities they’re chartered to serve has been fraught.
The Backstory podcast:
For many Americans, the storyline that played out on August 9  in Ferguson, Mo. — when an unarmed black teenager was fatally shot by a white police officer — is not a new one. But the sustained protests that followed, in which Ferguson police used military equipment for crowd control, have generated a new round of questioning about the role of local police in their communities.
So on this episode, we’re looking at the history of policing in America, and how the police departments we’re familiar with today began to take shape. And we’ll consider what happens when the police don’t protect those they serve….
Scholar Khalil Gibran Muhammad talks with Brian Balogh about how many ethnic groups have shed their criminal reputations through police service, and the more complicated legacy of early African-American officers.
Many ethnic groups, including the Irish and Italians, saw many individuals become police officers, which aided assimilation. African Americans have been blocked from that route.
Also: Technology has shaped the police from the beginning, from the invention of handcuffs to handguns to two-way radios to bodycams.