Murders are up nearly 17% from last year [PDF], shootings have increased by 23%, and the marijuana trade is to blame, according to NYPD Commissioner Bill Bratton. "In this city, people are killing each other over marijuana more so than anything that we had to deal with an '80s and '90s with heroin and cocaine," Bratton told reporters yesterday. "The seemingly innocent drug that's been legalized around the country."

Worse than when gang violence killed 523 people in upper Manhattan alone from 1983 to 1988? Worse than when more than half of 414 homicides catalogued between March and October of 1988 (we had a total of 328 in 2014) were deemed drug-related? Worse than 1990, when 2,245 people were murdered in New York City?

"I'd like to see what hard evidence there is that it's marijuana that's driving a deep-freeze winter shooting spike," says Eugene O'Donnell, a professor at John Jay College of Criminal Justice.

"I think what you're seeing here is that the commissioner is a little contorted at this point. He's trying to use community policing, and be the post-Bloomberg, post-Kelly, post-Garner commissioner, but he continues to cling onto the Kelly stuff—Broken Windows, zero tolerance. Squaring all of that together can't be done."

Bratton told reporters that marijuana was frequently a factor in robberies that lead to shootings. "We just see marijuana everywhere when we make these arrests, when we get these guns off the streets."

Mason Tvert, a spokesman for the Marijuana Policy Project, made an analogy: "While marijuana use is not linked to violent crime, marijuana prohibition is. Apparently [Bratton] didn't learn from his predecessors' struggles with violent crime associated with alcohol prohibition."

Jeffrey Fagan, a law professor at Columbia who teaches drug law and policy, agreed.

"It's hard to reconcile Commissioner Bratton's claim with experience in the places that have either legalized marijuana or increased access via medical marijuana," Fagan says. "By linking marijuana with violence here, which is just not the case elsewhere where it's legal, he's actually making a good claim for legalization."

Overall crime is down year-to-year. Felony assault has dropped by 18%; burglary is down 22%; crime on the subway is down by nearly 30%.

"We've had an extraordinary reduction in crime alongside an extraordinary reduction in police enforcement and activity," O'Donnell, a former NYPD officer, says, pointing to the huge decrease in stop-and-frisks and the recent (re-)decriminalization of marijuana. He calls Bratton's insistence on "these '70s, '80s, '90s, measurements" for crime "highly dubious."

"You have to take the long view. The city has changed, and it has nothing to do with the cops. There are $5 million condos in Greenpoint and Williamsburg—if that's not a major factor driving public safety, I don't know what is."

O'Donnell added, "You and I, and my students, we don't own this city anymore. We're just passing through."