Courtesy of Flickr user Abulic Monkey, under a Creative Commons license.

New York City police commissioner Bill Bratton and criminologist George Kelling, two of the earliest advocates of a policing strategy now widely known as "broken windows," have a lengthy article in the new City Journal defending the idea.

Kelling, along with the political scientist James Q. Wilson, wrote the 1982 Atlantic article that first popularized the phrase. Ever since, it has been used as shorthand for the broad idea that seemingly minor forms of neighborhood disorder — graffiti, panhandling, broken windows — beget more major criminal problems. If police focus on that small stuff, cracking down on subway fare jumpers or public drunks, residents will feel safer, neighborhoods will become more so, and serious criminals will be deterred.

The 30-year-old idea has come under particular attack following the death of Eric Garner in New York. Garner was approached by officers for selling loose cigarettes, the very kind of minor offense that "broken windows" theory targets. Garner ultimately died after one of those officers, trying to subdue him, wrapped an arm around his neck area.

Kelling and Bratton don't respond in particular to Garner's death, or to the specific criticism that he might not have died had police not directed so much force toward such a petty crime. They respond instead more broadly to critics who they say object "to the department’s long-standing practice of maintaining order in public spaces."

That's probably not how many critics would describe their objections. Still, Bratton and Kelling make some fair points. "Broken windows" (the idea that small signs of disorder matter) is not synonymous with stop-and-frisk (the tactic of stopping people suspected of committing or planning crimes, including distinctly non-petty ones). Randomized experiments have supported the argument that "broken windows" can work. And crime has notably declined in New York since the philosophy was first embraced there.

But in making this case, Bratton and Kelling also overstate the role that "broken windows" has played in making New York a safer place — or, at least, they understate the very likely possibility that many factors far beyond the control of law enforcement have contributed to making it so. This is the weakest part of their argument. After all, much of the debate over "broken windows" isn't about whether or not it's effective, but about how much credit it should get for making cities like New York safer.

Bratton and Kelling do their own defense a disservice by swatting away all of the other — not incompatible — explanations for why New York is no longer teeming with car thieves, drug dealers and prostitutes:

The academics who attribute crime drops to economic or demographic factors often work with macro data sets and draw unsubstantiated, far-fetched conclusions about street-level police work, which most have scarcely witnessed. These ivory-tower studies, frequently treated with reverence by the media, don’t prove what they purport to prove, and they fail to grasp how crime is managed in dense, urban settings.

These ivory-tower studies point out, for instance, that while crime was falling in New York in the era of "broken windows" and Compstat, it was falling across the U.S. (even internationally) in places that deployed neither. That doesn't mean that "broken windows" didn't help. But it does imply that the strategy, or even other police tactics, alone can't explain why New Yorkers should feel safer today than in 1990.

Bratton and Kelling, though, seem downright contemptuous of the idea that economic and demographic conditions might matter, too (which is dismissing the work of an awful lot of thoughtful people). And they appear to suggest here that anyone not involved in "street-level police work" is unqualified to weigh in on policing and crime. (It's also odd, as Eric Jaffe points out, that they dismiss academia within the scholarly pages of a think tank journal).

By this narrative, police innovation alone explains why New York City is safer (by implication, take that innovation away, and the city could descend back into criminal chaos at any time). Here, Bratton and Kelling evoke the city before "broken windows":

In the early 1990s, New Yorkers had a much different idea of normal social conditions from what they have today. “Normal” was removing your car radio and posting a sign in the window reading “No Radio” to discourage a break-in. Normal was subway patrons clustering together to protect themselves against predators. Normal was getting your windshield spat on and wiped with a dirty rag, or being “helped” by having your bags grabbed at Penn Station and then being forced to “tip.” Normal was Bryant Park closed and fenced off. And normal was 2,000 murders, 100,000 robberies, and 130,000 auto thefts, and the ever-present sense of danger.

New York City is a much different place today. Crime has been plummeting for two decades. The rate of crime decline has slowed in the past five years—as it would have to, after years of huge reductions—with some small upticks, but the general trend continues downward. Tourism is booming. Public spaces are safe. Property values have escalated. It’s a good place to live and work. Lawlessness no longer characterizes the subway system. These conditions didn’t just happen. They resulted from thousands of police interventions on the street, which restored order and civility across the five boroughs.

In fact, these conditions have probably resulted from many factors, police tactics among them. The Marshall Project recently rounded up 10 of the most popular theories for why urban crime has declined. So many exist — from the rise of legal abortion to the decline of lead-based fuel and paint — precisely because the phenomenon has proved so difficult to explain. Can we really dismiss, for instance, the fact that anti-theft technology in vehicles has grown much more sophisticated? Or the fact that the crack epidemic finally waned? Or that our increasingly cashless economy makes people harder targets for crime?

We recently wrote about a Chicago summer-jobs program that appears to have cut down on violent arrests by at-risk teens. Those results further support the notion that crime and violence (their presence) are intimately tied to economic opportunity (and its absence). How, then, can we argue that economic factors are irrelevant?

While it's hard to say exactly how much each of these factors matters, it's implausible that none of them do — that contested police tactics are the only thing standing between us and 1980s-era crime.