What happens when government not only pays people to work as police, but also gives them both authority and discretion to routinely use physical force against others in the course of their work? And what if, further, police are given broad deference – even immunity from serious consequences – for their use of force? What sort of people might that job attract?
United States law enforcement institutions cannot offset the predictable results of handing people a badge, weapons, and license to use whatever force they consider necessary to protect themselves and enforce the law. Rudolf Diels, first head of the Gestapo (German Secret Police, formed in 1933), candidly observed the results in his police institution:
The infliction of physical punishment is not every man’s job, and naturally we were only too glad to recruit men who were prepared to show no squeamishness at their task. Unfortunately, we knew nothing about the Freudian side of the business, and it was only after a number of instances of unnecessary flogging and meaningless cruelty that I tumbled to the fact that my organization had been attracting all the sadists in Germany and Austria without my knowledge for some time past. It had also been attracting unconscious sadists, i.e., men who did not know themselves that they had sadist leanings until they took part in a flogging. And finally it had actually been creating sadists. For it seems that corporal chastisement ultimately arouses sadistic leanings in apparently normal men and women.
Rudolf Diels
Federalist 
“Serial” podcast, Season Three, produced by Sarah Koenig (formerly of “This American Life”), spends a year following various cases that pass through one courthouse in Cleveland. The producers try to be fair but their findings are still pretty shocking. They expose a lot of disturbing police and prosecutorial behavior just by following some random cases. The call to reform the criminal justice system should not be a radical, leftist cause.
And, for those keeping score at home: Yes, U.S. police have become more militarized and more violent in recent years.
Just read this Restraining Order issued last year in which a U.S. District Court ordered law enforcement to stop attacking journalists covering riots in Portland. It rebuts a number of shameless arguments by government attorneys who opposed an restrictions on law enforcement officers’ discretion to abuse neutral observers who were clearly not doing anything wrong.