Editor’s note: David Simon is renowned for reporting on the hard realities of urban life. He worked for the Baltimore Sun for many years, wrote “Homicide: A Year on the Killing Streets” (1991) and co-wrote “The Corner: A Year in the Life of an Inner-City Neighborhood” (1997). He created the HBO series “The Wire” (2002–2008). The Marshall Project is a new public-interest journalism project focusing on criminal justice reform led by former New York Times editor Bill Keller. These excerpts are from a lengthy Q&A with Simon by Keller.

1. Baltimore’s war on drugs turned into a war on blacks. “Probable cause was destroyed by the drug war. It happened in stages, but even in the time that I was a police reporter, which would have been the early '80s to the early '90s, the need for police officers to address the basic rights of the people they were policing in Baltimore was minimized. It was done almost as a plan by the local government, by police commissioners and mayors, and it not only made everybody in these poor communities vulnerable to the most arbitrary behavior on the part of the police officers.”

2. Police didn’t need a reason to harass and arrest: “Probable cause from a Baltimore police officer has always been a tenuous thing. It’s a tenuous thing anywhere, but in Baltimore, in these high crime, heavily policed areas, it was even worse. When I came on, there were jokes about, ‘You know what probable cause is on Edmondson Avenue? You roll by in your radio car and the guy looks at you for two seconds too long.’ Probable cause was whatever you thought you could safely lie about when you got into district court.

3. Some of the most aggressive cops were Black: “It became clear that the most brutal cops in our sector of the Western District were black. The guys who would really kick your ass without thinking twice were black officers. If I had to guess and put a name on it, I’d say that at some point, the drug war was as much a function of class and social control as it was of racism. I think the two agendas are inextricably linked, and where one picks up and the other ends is hard to say. But when you have African-American officers beating the dog-piss out of people they’re supposed to be policing, and there isn't a white guy in the equation on a street level, it's pretty remarkable. But in some ways they were empowered. Back then, even before the advent of cell phones and digital cameras — which have been transforming in terms of documenting police violence — back then, you were much more vulnerable if you were white and you wanted to wail on somebody. You take out your nightstick and you’re white and you start hitting somebody, it has a completely different dynamic than if you were a black officer.

4. The drug war became a new war on the poor: “This was simply about keeping the poor down, and that war footing has been an excuse for everybody to operate outside the realm of procedure and law. And the city willingly and legally gave itself over to that, beginning with the drug-free zones and with the misuse of what are known on the street in the previous generation as ‘humbles.’ A humble is a cheap, inconsequential arrest that nonetheless gives the guy a night or two in jail before he sees a court commissioner. You can arrest people on “failure to obey,” it’s a humble. Loitering is a humble. These things were used by police officers going back to the ‘60s in Baltimore. It’s the ultimate recourse for a cop who doesn't like somebody who's looking at him the wrong way.”

5. As mayor, Martin O’Malley made it much worse: “The drug war began it, certainly, but the stake through the heart of police procedure in Baltimore was Martin O’Malley [who is expected to run for president as a Democrat in 2016]. He destroyed police work in some real respects. Whatever was left of it when he took over the police department, if there were two bricks together that were the suggestion of an edifice that you could have called meaningful police work, he found a way to pull them apart…

“What happened under his watch as Baltimore’s mayor was that he wanted to be governor. And at a certain point, with the crime rate high and with his promises of a reduced crime rate on the line, he put no faith in real policing…

“The department began sweeping the streets of the inner city, taking bodies on ridiculous humbles, mass arrests, sending thousands of people to city jail, hundreds every night, thousands in a month. They actually had police supervisors stationed with printed forms at the city jail – forms that said, essentially, you can go home now if you sign away any liability the city has for false arrest, or you can not sign the form and spend the weekend in jail until you see a court commissioner. And tens of thousands of people signed that form.

“The city eventually got sued by the ACLU and had to settle, but O’Malley defends the wholesale denigration of black civil rights to this day. Never mind what it did to your jury pool: now every single person of color in Baltimore knows the police will lie — and that's your jury pool for when you really need them for when you have, say, a felony murder case. But what it taught the police department was that they could go a step beyond the manufactured probable cause, and the drug-free zones and the humbles – the targeting of suspects through less-than-constitutional procedure. Now, the mass arrests made clear, we can lock up anybody, we don't have to figure out who's committing crimes, we don't have to investigate anything, we just gather all the bodies — everybody goes to jail. And yet people were scared enough of crime in those years that O’Malley had his supporters for this policy, council members and community leaders who thought, They’re all just thugs. But they weren’t."