In 1951, Harry Truman fired Gen. Douglas MacArthur during the Korean War. The two never got along, but that wasn’t why Truman canned him. “I didn’t fire him because he was a dumb son of a bitch, although he was,” explained Truman after the fact. “I fired him because he wouldn’t respect the authority of the president.” You expect soldiers of all ranks to understand the need to respect the chain of command, regardless of personal feelings.

Soldiers—and cops, too.

Which is one big reason the display by members of the New York Police Department at the funeral of slain patrolman Rafael Ramos is particularly disturbing. At Ramos’s funeral service Saturday, NYPD rank-and-file—along with members of police forces attending from around the country—turned their backs when Mayor Bill de Blasio delivered his eulogy. This was a very public fuck you to a politician widely perceived by conservatives and law-and-order types as weak on crime and in the pocket of social-justice warriors. Yet the cops’ protest illustrates exactly what drives so much fear of the police: the worry that cops react emotionally and impulsively in situations that call for cool rationality and a reliance on training and strategic restraint. “It wasn’t planned,” said one of the protesters. “Everyone just started doing it.”

“I certainly don’t support that action,” said NYPD Commissioner Bill Bratton. “I think it was very inappropriate at that event.” Bratton—whom de Blasio appointed and who first served as commissioner under tough-guy Rudy Giuliani—is very much in the tradition of “Give ’em Hell” Harry Truman. Which is to say that he at times lets his emotions get the best of him, as when he spuriously implicated President Obama for strained relations between police and citizens, saying that cops feel as if they “are under attack from the federal government at the highest levels.”

But if de Blasio is in fact soft on crime, he made an exceedingly strange choice in tapping Bratton, credited with helping drive crime down in ’90s New York under Giuliani and in 21st-century Los Angeles, to lead the NYPD. As a cop’s cop, Bratton is in the best possible situation to restore respect for authority among New York’s finest.

The NYPD—and cops more generally—have a public relations problem in the wake of the Michael Brown, Eric Garner, and a long string of other cases. Acting like a bunch of high-school jocks protesting a ban on keg parties isn’t exactly going to win over many hearts and minds. It’s exactly the inability of the cops who killed Garner to restrain themselves that bothered so may of us who watched the video of the encounter. The same goes for the hysterical overreaction and escalation of force used against protesters in Ferguson over the summer.

Yes, cops are under stress and tension (though their jobs are far less dangerous than normally supposed). But they are trained to rise above mere emotional responses; that’s one of the reasons they are given a state-sanctioned monopoly on force. Yet even after the funeral protest, de Blasio was booed and heckled while addressing a new class of recruits as well.

That’s not the worst of it. In the wake of the murders of Ramos and Liu, the head of the Patrolmen’s Benevolent Association, Patrick Lynch, immediately issued a statement claiming that “there’s blood on many hands tonight” and “that blood on the hands starts at City Hall in the office of the mayor.” In fact, Ramos and Liu were killed by deranged gunman Ismaaiyl Brinsley, a career criminal who shot his girlfriend in Baltimore, drove to New York, and bragged about “putting wings on pigs.”

I’m no de Blasio partisan, but the mayor’s willingness to entertain the notion that Eric Garner needn’t have died in police custody has about as much to do with the murders of Ramos and Liu as Sarah Palin’s defense of the Second Amendment had to do with madman Jared Loughner’s shooting of Gabby Giffords. Which is to say: nothing.

The New York Post reports that an email circulating among the NYPD declares, “We have… become a ‘wartime’ Police Department… We will act accordingly.” The email further advised that “two units are to respond to EVERY call,” regardless of the severity of the situation or “the opinion of the patrol supervisor,” a tactic that, the Post notes, not only bucks the chain of command but would “effectively cut in half the NYPD’s patrol strength.”

Prior to the killing of Ramos and Liu, the last time an NYPD cop was ambushed in such a way was in 1988; their deaths were the first in the line of fire since 2011. Yet the email references the 1970s, “when police officers were ambushed and executed on a regular basis.” We normally associate such massive displays of overreaction with pearl-clutching undergraduates calling for “trigger warnings” when faced with reading The Great Gatsby.

Echoing Truman talking about MacArthur, Bratton has said that it was wrong for cops to disrespect de Blasio at the Ramos service because “he is the mayor of New York [and] he was there representing the citizens of New York to express their remorse and their regret at that death.” The police commissioner is sitting down with the unions representing the NYPD rank and file to work through issues that range “far beyond race relations in this city” and include contract disputes about pay, benefits, and more (these latter issues suggest that police outrage at city leaders may be as much a negotiating tactic as in-the-moment reactions).

Based on the responses so far by the Patrolmen’s Benevolent Association and the cops themselves, those won’t be pleasant conversations. But Bratton himself has granted that black people “of all classes” have told him they fear the police. Such attitudes join the growing discomfort with militarized police who always seem ready to escalate force and refuse to acknowledge any culpability when things go wrong.

As Bratton and the NYPD start talking among themselves, the commissioner will do well to paraphrase another Trumanism: “The buck stops here.” The police cannot ultimately control public opinion unilaterally. What they can do, though, is acknowledge that a change in their attitudes, behavior, policies, and willingness to engage in discussions about how people see them can help them win back the public trust.