Patrolmen's Benevolent Association president Pat Lynch's warning to Mayor Bill de Blasio to avoid police funerals underscores the deteriorating relationship between the mayor and the police -- one that may be too strained to heal.

As PBA spokesman Al O'Leary put it, "The public underestimates how angry police officers are at the mayor." For NYC mayors and police commissioners, attending police funerals is a must.

Lynch's warning to de Blasio and City Council Speaker Melissa Mark-Viverito -- that their attendance "is an insult to that officer's memory and sacrifice" -- may have been done to shock. But it was also a protest.

Either way, it may have unintended consequences. For one thing, Lynch weakens his friend, Police Commissioner Bill Bratton.

On the other hand, how would you describe de Blasio's rhetoric? During his time as mayor, his words and deeds concerning the police reflect the naïvete of John Lindsay and the arrogance of Rudy Giuliani.

Lynch's comments were set off by de Blasio's remarks after a grand jury declined to indict NYPD Officer Daniel Pantaleo in the death of Eric Garner. Referring to his biracial son, Dante, the mayor said, "We've had to literally train him, as families have all over this city for decades, in how to take special care in any encounter he has with the police officers who are there to protect him."

Many cops were furious at the remark and accused him of injecting race.

Over the past 20 years, the NYPD has been credited with dramatically reducing the city's crime rate.

But with the election of de Blasio, which included an agenda that called for recalibrating the NYPD's stop-and-frisk policy, and Garner's death, cops have been reviled by protesters. On Saturday, two lieutenants near the Brooklyn Bridge were assaulted after they tried to stop a man from throwing a garbage can at officers.

So where do we go from here? Dennis Gonzalez, the president of the NYPD Hispanic Society, representing 9,500 police officers, has called for de Blasio and the City Council to "denounce these disgraceful protests . . . Many elected officials are quick to speak out against police officers, but now that we need them to calm the city, where is their press conference on the steps of City Hall? Their silence is deafening."