Despite an enormous drop in the crime rate [world-wide and in the US] over the last 30 years America's law enforcement have grown ever more so violent and vindictive. Some might say "See that proves it's working". Wrong, because the same trend happened worldwide in other advanced countries that haven't become police states like America. Good examples are Sweden, Canada and Australia.
This what a cop looked like in the 1970's:
This is what they look like today: