The leaflet was meant to highlight anger on the part of police officers with the mayor of New York. It encouraged officers to fill their names in on a document that read, ”I, . . ., a New York City police officer, want all of my family and brother officers who read this to know [that] in the event of my death [the mayor and his police commissioner should] be denied attendance of any memorial service in my honor as their attendance would only bring disgrace to my memory.”

That’s how deep the divisions ran.

Yes, “ran.”

The leaflet mentioned above was distributed in 1997. The mayor in question was Rudolph Giuliani, and The New York Times reported on rank-and-file members of the powerful Patrolmen’s Benevolent Association urging fellow officers to sign the documents. Though the union did not officially sanction the jab at the mayor, its circulation among officers “demonstrates the depths of their discontent,” reported the Times in an article on a contract dispute in which Giuliani was taking a hard line against pay increases.

Today NYPD officers can download a similar document from the PBA website and sign it as one of many protests against Mayor Bill de Blasio’s recognition of tensions between minority communities and the NYPD in the aftermath of a grand jury decision not to indict an officer who was videotaped choking Eric Garner shortly before the Staten Island man’s death. Those protests drew national attention Saturday, as officers turned their backs on images of the mayor delivering a eulogy at the funeral service for NYPD Officer Rafael Ramos, who was shot and killed a week earlier along with his partner, Wenjian Liu, in their squad car.

As raw as the tensions are today in New York, it is important to remember that the city’s mayors have frequently clashed with the police union and its leadership. The clashes have been intense, they have been bitter and they have often extended over a number of years. Some mayors who have been at odds with the PBA—like David Dinkins, who established the framework for the current incarnation of the city’s Civilian Complaint Review Board—have been narrowly defeated for re-election. And there have already been plenty of attempts to compare Dinkins and de Blasio (a former Dinkins aide). But Dinkins is the exception, not the rule.

For the most part, New York mayors who have clashed with the PBA (going back to epic figures such as Fiorello La Guardia and including long-serving managers such as Robert Wagner Jr.) have survived politically. That may be the most important lesson for Mayor de Blasio to take away from the current conflict—which comes amid broader wrangling over contracts, pensions and reform of the department.

In the same year that the anti-Giuliani leaflet circulated, he was easily re-elected. (The bitterness remained, however. When Giuliani made a bid for the presidency in 2008, PBA President Patrick Lynch declared, “The New York City Patrolmen’s Benevolent Association could never support Rudy Giuliani for any elected office.” Lynch complained that “there are simply not enough NYPD police officers to keep this city safe, and it is Giuliani’s fault.”)

And don’t forget about John Lindsay. Elected on a promise to reform the police department, Lindsay appointed former federal judge Lawrence Walsh to head a Law Enforcement Task Force charged with reviewing police operations, appointed a reform-minded new police commissioner and worked closely with the NYPD’s new chief inspector, Sanford Garelik, who talked of “humanizing the department.” In his brilliant book on the era, The Ungovernable City: John Lindsay and His Struggle to Save New York (Basic Books), Vincent Cannato devotes a full chapter to Lindsay’s conflicts with the PBA, especially a 1966 referendum battle over the development of an earlier version of the Civilian Complaint Review Board.

Lindsay lost that fight, and clashed continually with the PBA—so much so that the spokesman for the PBA, Norman Frank, prepared to mount a challenge to the mayor’s 1969 re-election bid. Frank stepped aside when more prominent “law-and-order” candidates entered the race. A Republican “law-and-order” candidate, state Senator John Marchi, beat Lindsay in the GOP primary, while another “law-and-order” contender, City Comptroller Mario Procaccino, won the Democratic nod over four more liberal contenders. It seemed for a moment that Lindsay was doomed, yet he and his supporters regrouped, mounting a fall campaign on the Liberal Party line. Uniting reformers from across the partisan spectrum, and with strong support from minority communities, Lindsay easily beat Procaccino and Marchi that November. He did so leading a ticket that included Garelik, who was elected city council president. Among his campaign themes was a reminder that the mayor’s emphasis on dialing down tensions and improving police-community relations had kept New York relatively calm while other cities exploded with riots.

Years later, in an essay on Lindsay’s mayoralty, author (and one-time assistant budget director for New York) Charles R. Morris observed that, while Lindsay’s reforms were “hard for cops to swallow,” the fact remained that “on any fair judgment, the strategy mostly worked. New York City had multiple dangerous flare-ups, but they never degenerated into the all-out police-ghetto warfare, with the shocking death tolls, that were seen in Los Angeles, Detroit, and Newark.”

“Lindsay’s success in calming New York drew wide attention, especially by contrast with the police-against-the-radicals free-for-all during the 1968 Chicago Democratic convention,” continued Morris. “For a brief period, Lindsay was ‘America’s Mayor,’ and other mayors began consciously to pattern their policies after his. Over the next decade or so, the New York police tactics became standard practice in almost all major cities.”

New York is different from the city it was in the late 1960s, just as it is different from the city it was in the 1990s. The media landscape has changed, as has the political landscape. And de Blasio is different in many ways from his predecessors. But that does not mean that this mayor cannot, or will not, learn the lessons of the past and apply them in the future.

In his eulogy for Officer Ramos, Mayor de Blasio preached a gospel of reconciliation that sought to reduce the current animosity, describing how police officers “help make a place that otherwise would be torn with strife a place of peace.” The mayoral olive branch was not accepted Saturday, just as previous efforts by previous mayors to ease tensions with the PBA have hit rough spots. This is a part of the story of big-city policing and politics. But it is not the whole story. The whole story tells us that it is possible for a strong mayor to get through hard times that include clashes with a strong police union, to propose and implement reforms that the mayor, many police officers and most citizens know to be necessary, and to survive politically. This is the historical reality, as opposed to the media-frenzy spin of the moment. And it is this reality that Mayor de Blasio would do well to keep in mind through the weeks and months to come.