DA Larry Krasner and Philly FOP have an early spat over … what?

It could be dubbed "the Great Semantics Dispute of Winter 2018."

Or perhaps The First Fight, the pilot episode in a TV series bound to record many more programs.

Maybe the only surprise about the war of words that erupted Thursday evening between the city's police union and the district attorney — their first public spat since Larry Krasner was sworn in as prosecutor earlier this year — was that it took two months to happen.

Well, that and the unusual source of the debate. Let's rewind.

On Thursday afternoon, a letter from John McNesby, president of Fraternal Order of Police Lodge 5, started circulating among cops and lawyers in town. It accused Krasner — who as a defense attorney regularly filed police misconduct lawsuits — of delivering misguided advice this week to recruits at the Police Academy in Holmesburg about how and when to use their service weapons.

"Unfortunately, you have been exposed to a ridiculous and dangerous presentation by the current district attorney of Philadelphia," McNesby's letter said. "He has intentionally sought to endanger your lives by his outrageous efforts to 'instruct' you on the use of your firearm. You are officially urged to completely disregard his dangerous and despicable remarks."

Meanwhile, Krasner's spokesman, Ben Waxman, tweeted a statement calling the letter's assertions a "total lie" and saying  Krasner had simply gone over scenarios in which prosecutors may or may not seek criminal charges over police firing shots. And, said Waxman, there was video to back him up.

On Friday morning, Waxman played the video for a reporter. Krasner can be seen discussing several scenarios, including one in which officers fatally shoot an unarmed and mentally ill man who had reached for another officer's gun and struggled with him over it.

The video shows Krasner referring to "some mistakes that were made" in that scenario, and saying the man could have survived had the officers not displayed "an eagerness to shoot center mass."

But, the video also shows him saying: "That does not mean those officers committed any crime. That does not mean there's any disciplinary violation. That means those officers acted with preliminary information, under a whole lot of time pressure with things developing quickly, [and] made an honest mistake. And this District Attorney's Office is not going to second-guess that."

He suggested training could help guide when officers choose to fire their weapons, and — in a line that likely riled police the most — whether every shot needs to be "center mass." Police and military members have for decades been trained to shoot for a suspect's chest or back, as opposed to arms or legs, to more effectively stop a threat.

Krasner added that he would leave training decisions to the Police Department, then said: "If you have come here with the notion that the District Attorney's Office is out there to screw you if you make an honest mistake, we're not."

McNesby said he didn't care what the video of Krasner's speech showed: "Video or no, he shouldn't be up there," McNesby said Friday. "He's not qualified. He's not an expert. He's not trained."

McNesby acknowledged Thursday that he had not witnessed Krasner's presentation, but said he had received several phone calls after it ended. He said Krasner had no business giving tactical advice to police — especially if that advice included aiming for anything other than "center mass," guidance that McNesby said could put officers' lives in danger.

"Our academy staff was aware," McNesby said. "They had to go back and readdress the class."

He added that the academy staff was still angry Friday about Krasner's comments and might block him from speaking to classes in the future.

Commissioner Richard Ross declined to comment Friday, except to say that he had a conversation with Krasner about the matter and is content to move on.

Meanwhile, Rochelle Bilal, president of the Guardian Civic League, a black officers' organization that invited Krasner to speak and had supported him during the campaign, said Thursday that McNesby knew she was there but did not reach out to her before issuing his letter, which she described as "half-cocked."

"He didn't ask me. He didn't call me," said Bilal. "He has my number. He should've asked me."

As the controversy swirled, 101 police recruits were sworn in Friday morning at Temple University.

The dustup had the qualities of a proxy war, given the philosophical disagreements between at least a portion of the police force — whose members are accustomed to arresting suspected criminals — and Krasner, whose major announcements so far have included reducing the use of cash bail and ending prosecution of certain marijuana crimes.

Things got so frosty between Krasner and McNesby last year that U.S. Rep. Robert Brady, chairman of the Democratic City Committee, had to set up a meeting to make peace.