In 1990, soon after William Bratton became chief of the New York City Transit Police, he directed his officers to strictly enforce the laws against fare evaders. It was the start of what would eventually become a citywide campaign to curb serious crime by cracking down on relatively minor offenses. The goal was to establish an expectation of order and lawfulness: If the authorities made it clear that even low-level violations would be suppressed, then disorder would be far less likely to escalate to more violent and destructive crimes.

Restoring a sense of safety to New York’s subways was a key focus for Bratton, who would later become commissioner of the New York Police Department (and hold similar posts in Boston and Los Angeles). As thousands of turnstile jumpers began getting arrested and sent to the city’s criminal courts, a remarkable transformation took place. In 1990, there were 17,497 felonies committed against transit passengers; by 2015, that number had plummeted to 2,502. “New Yorkers once endured 48 felonies a day in the transit system,” the New York Post reported in 2016. “Now it’s fewer than seven.”

But then, with crime having fallen to record lows, Manhattan district attorney Cyrus Vance Jr. announced that his office would no longer pursue criminal charges against most people arrested for evading fares. Instead, The New York Times reported in 2017, “those defendants generally will be diverted into community service or social programs.” As it was, the overwhelming majority of subway cheats already got off lightly. About three-quarters of those cited by the police for not paying received a civil summons and had to pay a fine. Of the nearly 10,000 people charged in Manhattan with fare evasion in 2016, only 320 people ended up in jail, most for just a few weeks. But under Vance’s new policy, it became futile for police to keep arresting fare evaders. And that in turn deprived the city of the benefits associated with searching arrestees — searches that often turned up contraband or flushed out criminals with numerous prior arrests.

Within two years, the effect of the new policy was unmistakable. “1 in 5 Bus Riders in New York City Evades the Fare, Far Worse Than Elsewhere,” a front-page Times story was headlined in 2019. With law enforcement no longer going after passengers for cheating on their fare, more and more passengers cheated. “Fare evasion is on the rise on the subway and buses, costing the system $225 million in lost revenue last year,” the Times reported. The problem was especially severe on buses, where there are no turnstiles to block riders’ access. Riders “knew they would not get in trouble” for nonpayment, the story noted. Many “simply felt no obligation to pay.”

Passengers in other cities weren’t nearly so carefree about stealing. In Paris, for example, where 1,200 staffers patrolled the transit system and issued a million fines each year, the fare evasion rate was 11 percent. In London, where evaders face fines as steep as $1,300, all but 1.5 percent of bus passengers paid their fares. But in New York, where progressive activists and prosecutors regarded fare enforcement as illiberal and even racially inequitable, passengers inclined to ride without paying faced no obstacle other than their own sense of right and wrong.

Fast-forward five years. In another front-page story last week, the Times updated the 2019 figures. Now it isn’t a fifth of bus riders who don’t pay what they owe. It’s half.

“Every weekday in New York City, close to one million bus riders — roughly one out of every two passengers — board without paying,” the paper related. In 2022, the city lost $315 million to fare evaders on its buses and another $285 million on the subways. “Yet public officials have done relatively little to collect the lost revenue from bus riders.”

Citing unnamed “experts,” the Times speculated that so many passengers aren’t paying “because they cannot afford the fare.” Or because sluggish bus service “is simply not worth the price of admission.” Or because of a “perception” that fares are optional, since bus rides were free for a few months in 2020 during the pandemic.

But the real reason for the epidemic of nonpayment is perfectly obvious. For seven years, New York City has encouraged fare beating by declining to arrest and punish offenders. The clearer it became that there was no penalty for disregarding the law, the more New Yorkers decided that disregarding the law was OK.

The same phenomenon is apparent in other areas. When California downgraded shoplifting to a misdemeanor if the merchandise stolen was worth less than $950, it signaled that retail theft would be tolerated — and the result has been a tidal wave of ransacked stores. When cities across the country stopped enforcing laws against the public use of drugs and courts struck down anti-vagrancy ordinances, they opened the door to squalid public encampments infested with violence, addiction, and filth.

Expectations are a powerful factor in social interaction. It wasn’t that long ago that dog owners were not expected to clean up after their pets and that smoking in the presence of other people was unremarkable. As the rules changed, so did people’s behavior — and so did expectations about how people were to behave.

But expectations can change in both directions. Sometimes changes reduce misconduct, lawlessness, and crudity. All too often, however, they increase it. New York learned a powerful lesson in the 1990s and 2000s about the enormous improvement that could result from cracking down on comparatively small public offenses. Yet having learned the lesson, it proceeded to forget it. Now fare evasion is once again entrenched in the city’s public transportation — and once again the city feels less safe, less clean, and less sound.

It isn’t only in New York that standards are eroding, that bad behavior is increasing, and that enforcement of norms is dwindling. And it isn’t only in New York that a menacing sense of social disorder is spreading.