With his slicked-back hair, Queens accent and entourage of mostly white, male union lieutenants, Patrick J. Lynch moves through New York as the rough-around-the-edges, unapologetic labor leader for more than 22,000 street officers.

His public persona — greeting officers on the street and delivering speeches with a cadence that reaches for the Kennedyesque — ranks him among the most recognizable police officers in the city.

But behind the raffish facade is a shrewd tactician who, according to his allies and those who have faced off against him, has proved adept at negotiating deals when it fits his interests, and tangling with mayoral administrations, Democrat and Republican alike, when it has not. It has kept him at the helm of the Patrolmen’s Benevolent Association for 15 years, representing the bulk of the nation’s largest police force even as it bears less and less resemblance to his Irish Catholic roots.

His latest battle, though, far eclipses anything before.

Amid the furious national debate over race and policing, his pugilistic defense of police officers and his vitriolic critiques of Mayor Bill de Blasio have been seen across the country in the days since two police officers were killed in Brooklyn.

Patrick Lynch, the president of the Patrolmen’s Benevolent Association, blamed the killing of two New York police officers on Mayor Bill de Blasio, saying the blood “starts on the steps of city hall.”

“For years, Pat was not the only voice of support for police,” said Al O’Leary, the union’s spokesman. “And now he is because there is no support for the police in City Hall.”

Mr. Lynch, 51, declined requests for an interview and has lowered his profile since Saturday, when the officers were killed. But his last words that night still echo, the most provocative public statements in a career of fiery rhetoric.

“There is blood on many hands, from those that incited violence under the guise of protest to try to tear down what police officers did every day,” Mr. Lynch said at the hospital where the mortally wounded officers had been taken. “That blood on the hands starts on the steps of City Hall in the office of the mayor.”

In laying the blame for the killings on the doorstep of a first-term liberal mayor, he also strained his relationship with William J. Bratton, the police commissioner, who had sought to bring the union chief back into the department’s embrace after years of estrangement.

The broadside by Mr. Lynch prompted former Mayor Rudolph W. Giuliani, a law-and-order Republican, to come to the defense of the mayor, a Democrat. “The blood is not on his hands,” Mr. Giuliani said on Sunday in a radio interview.

Even before the fatal shootings, Mr. Lynch had been waging an increasingly pointed campaign against Mr. de Blasio over the mayor’s response to the wave of demonstrations that followed a Staten Island grand jury’s decision not indict a police officer in the death of Eric Garner.

Mr. Lynch urged officers to bar the mayor from their own funerals if they died in the line of duty. The effort, while publicly backed by only a tiny fraction, signaled the depths of discontent among the rank and file.

But Mr. Lynch’s invective in recent days deepened the rift between the police and the de Blasio administration, which had made repairing relations between officers and the city’s minority communities a priority.

Even before the hospital diatribe, Mr. Bratton had said that Mr. Lynch had gone “too far.”

How widely shared that sentiment is and whether Mr. Lynch will win another term as union president next year are questions likely to animate discussions in the coming months. No formidable opponents have emerged, said John F. Driscoll, a retired captain who once led the Captain’s Endowment Association and remains in contact with many officers.

Mr. Driscoll said that for some, though, it might simply be a time for a new voice.

His members have been working without a contract since June 2010; negotiations broke down with the city and are headed to arbitration.

Both the mayor and police commissioner have suggested Mr. Lynch’s views do not reflect those of all officers.

Mr. Lynch entered the union’s leadership ranks in the early 1990s during a period of retrenchment for the union. He began as an officer in Williamsburg, Brooklyn, where a sergeant suggested he should put up his name for a union position, saying “Hey, Lynch, you’ve got a big mouth, why don’t you run?”

In 1999, he became the youngest president in the union’s history.

By 2004, he was flexing his organizing muscle during contract negotiations, harrying Mayor Michael R. Bloomberg outside public events with large groups of off-duty officers whose chants and comments edged close enough to threats to draw the attention of the Police Department itself, which sent a video team to record the protests.

The union’s actions exposed a widening divide between Mr. Lynch and Raymond W. Kelly, the police commissioner at the time. Earlier that year an officer fatally shot an unarmed black man, Timothy Stansbury, on the roof of a Brooklyn housing project. Almost immediately, Mr. Kelly said the shooting appeared to be unjustified.

It might as well have been a declaration of war to Mr. Lynch, who lashed out. But that response did not sit with Mr. Kelly, a former Marine with little tolerance for dissent.

Mr. Lynch’s stout defense of officers is not new. He has done so when there is ample evidence of police misconduct — standing by the officers who killed Amadou Diallo in 1999 or defending one who shoved a bicyclist to the ground during a protest ride in 2008.

His face was so familiar to people in government that sensitive contract negotiations during the Bloomberg administration were held far from in City Hall.

“When Pat Lynch walks into the mayor’s side of City Hall, it gets noticed,” said Edward Skyler, a former deputy mayor, who chose more private spaces like Gracie Mansion or a Gramercy coffee shop for contract discussions.

Mr. Lynch earns about $175,000 a year, roughly $76,000 from his job as an officer and $98,000 from the union, according to its most recent tax filing.

For much of the Bloomberg years, Mr. Kelly kept Mr. Lynch from most official activities at Police Headquarters.

That changed under Mr. Bratton, who invited Mr. Lynch and other union leaders to sit on the dais at official ceremonies, gave them office space inside Police Headquarters and consulted Mr. Lynch on officer morale, learning from him at the start of the year that it was “awful.”

Instead, morale sank further, even as his chief complaint by the end of the Bloomberg administration, that officers had to fulfill quotas for stop-and-frisk activity, became moot. This year, recorded stops are at their lowest levels in a decade.

And Mr. Lynch’s megaphone appeared to grow only louder, despite his return to the department’s fold.

Officers, who said in interviews they felt the de Blasio administration did not have their back, now are haunted by the killings of Officers Wenjian Liu and Rafael Ramos, who were ambushed in their patrol car on Saturday afternoon in Bedford-Stuyvesant.

Mr. Lynch, nearly always dressed in a suit in public, wore his patrol uniform to visit the memorial in Brooklyn accompanied by one of his sons, also in uniform.

Like a politician, he adapts his language to his audience, at times using words, like describing arrested suspects as “mutts,” that working-class officers can relate to.

But Mr. Lynch’s comments attacking the mayor come from a place of personal feeling, Mr. O’Leary, his spokesman, said. His youngest son is set to graduate from the Police Academy in January.

“It was gun and shield day the other day,” said one longtime associate of Mr. Lynch, describing the moment when cadets are given their police hardware. “And he was there.”

http://www.nycpba.org/archive/nyt/14/nyt-141224-profile.html