This is an interesting short interview with libertarian Radley Balko on police practices and prosecutors. All of it is worth reading, but I would draw your attention particularly to this:
DIA: You’ve written about the creeping militarisation of law enforcement in America. How has this trend manifested itself and what are the consequences for the quality of policing?
Mr Balko: The most obvious way it has manifested itself is in the explosion in the use of SWAT teams and similar paramilitary police units over the last 25 years. The criminologist Peter Kraska has surveyed their use over that time. He’s found that the total number of SWAT-team deployments in the 1970s was a few hundred times per year, over the entire country. By the 1980s, it was a few thousand times per year. And by around 2005, Mr Kraska estimates around 50,000 times per year. The surge has been driven entirely by the drug war, with the vast majority of SWAT deployments being used to serve drug-related search warrants.
This has led to a militaristic mindset among America’s police departments, beyond just SWAT teams. Driven by “war on crime” and “war on drugs” rhetoric set by political leaders, police officers have increasingly taken on the psyche of soldiers. There’s a pervasive and troubling “us versus them” attitude in policing today. Policing has become more reactionary, more aggressive, and it’s poisoning the relationship between the police and the communities they serve.
I should add that I don’t think police officers themselves are to blame for this, nor, obviously, are all police officers guilty of it. These are problems spawned by 35 years or so of bad policies set by politicians. That’s really where any reform would need to start.