THE causes of the impressive reduction in New York’s crime rate are a perennial subject of debate, but the police department’s decision to take minor crimes seriously certainly played its part. In 1990 the then head of the transit police, Bill Bratton, directed his officers to arrest as many turnstile-jumpers as possible. They found that one in seven arrested was wanted for other crimes, and that one in 20 carried a knife, gun or other weapon. Within a year, subway crime was down 30%. In 1994 Mr Bratton became head of the New York Police Department (NYPD), and took what he had done on the subway to the city’s then very mean streets. Since 1990, crime in the Big Apple has fallen dramatically and stayed low. New Yorkers are worried that this may be about to change.

Many of the city’s officers have recently decided not to bother enforcing the law at all for minor things. They are doing this out of pique at the city’s mayor, Bill de Blasio, who criticised the police after an officer inadvertently killed a civilian while making an arrest last year. (Many New Yorkers vented their outrage far more loudly.) During the first week of 2015, New York’s finest arrested just three people for jumping turnstiles. Over the same week in 2014, they nabbed more than 400.

Arrests across the city are down by more than half. The number of summonses issued for minor offences and traffic and parking violations have fallen by more than 90% compared with the same period last year. Criminal court judges are twiddling their thumbs as their dockets empty. One police officer apparently had so much free time on his hands that he injured himself while fooling around on the bonnet of his moving squad car.

Relations between the mayor and the rank-and-file are fraught. They began to sour after a grand jury opted not to indict the officer who killed Eric Garner in July. The protests that erupted were mostly peaceful, but a few protesters chanted that they wanted dead cops. The NYPD has shown remarkable restraint, politeness and at times kindness towards protesters, even those who were trying to provoke them. Mr de Blasio said he worried that his son, who is black, might not be safe from the police. That did not go down well with cops, many of whom are black themselves. They were already feeling besieged when two officers were targeted and killed last month by a deranged gunman who had made threats against police on social media. Thousands of police attended the funerals. When the mayor appeared on screen to eulogise the dead officers, many furiously turned their backs on him.

Mr Bratton, once again the city’s police commissioner, said the protest was inappropriate for a funeral. Pat Lynch, the head of the Patrolman’s Benevolent Association (their union), said Mr de Blasio had blood on his hands. It is perhaps no coincidence that the tension comes just when the police are in a contract dispute with City Hall.

Mr Lynch says the showdown was not started, and is not supported, by the union (it is illegal for police officers to strike). He points out that two other police officers who were shot on January 5th were about to go off-duty and head home when they turned back to respond to a robbery. As unhelpful and divisive as Mr Lynch’s rhetoric can be, the union he heads does not control officers’ actions. “The rage at this point is ahead of them and it has been festering for a while,” says one retired cop.

Mr Bratton, who is caught between his officers and the mayor, is still respected by his department. But Gene O’Donnell, a former police officer turned lecturer at John Jay College of Criminal Justice, thinks the police insubordination could transform Mr Bratton from “one of our own” into a warrior for Mr de Blasio. On January 7th the commissioner met union heads to discuss safety and morale. It did not go well. The mayor spent the afternoon swearing in the newest batch of police recruits. They were signing up for a tough job, he said. He also told them they were joining at a crucial time in history, a time when he intends to “draw this police department closer and closer to the communities it serves.” Right now they could not be farther apart.