Rahm Emanuel began his first inaugural address, that long ago cloudless day in May 2011, by talking about the need to improve the schools, then quickly shifted to the violence plaguing the children attending those schools.

“We must make our streets safer,” he said, citing a grim toll that “shames the living” and “should prod all of us” to find ways to stem the bloodshed. He offered, as hope to the city, his new police superintendent, Garry McCarthy.

“Our new police chief understands this,” Emanuel said. “He is the right man at the right time for the right job.”

Now, four years later, the city is transfixed by the specter of police, who work for that right man at the right time, not as the solution to the slaughter of the city’s children but as a cause of it.

On Tuesday, Jason Van Dyke, 37, became the first police officer in 34 years to be charged with first-degree murder for a killing committed during the execution of his duties. He was charged with firing 16 shots into 17-year-old Laquan McDonald in October 2014, an act captured on the dashboard camera, a “graphic…violent…chilling” video, in the words of Cook County State’s Attorney Anita Alvarez, bringing the charges just before the video is to be released. “This video will tear at the heart of all Chicagoans.”

Emanuel described the video as “hideous” without even seeing it, and tried to turn its release into a carnival of spin, hype and, ludicrously, hope, no doubt under his “let no crisis go wasted” philosophy. I couldn’t be the only viewer watching the mayor tap dance Tuesday evening and think: “Just shut up already and release the video.” Emanuel was trying to soften the blow, not to us, but to him. This makes him look bad or, rather, worse. Murders were up already — this September had 60 murders, making killings up 21 percent over the year before. Now, with the city reeling in horror, violence in Chicago is becoming the third leg in the tripod of Rahm’s failure as a mayor, growing into stark relief in his second and almost certainly final term: inability to solve the pension crisis, the broken and deteriorating schools, and bloodshed that not only shatters families here but stains the city’s reputation worldwide.

Will the video spark riots that further besmirch Rahm’s Chicago? Or just be an anti-climax after all that build-up? To say riots are coming could be the racism of low expectations. If African-American sections of Chicago rioted every time a cop did something wrong, it’s all they’d ever do. Nobody rioted after a judge waved police officer Dante Servin out of a courtroom last April, explaining that he couldn’t be found guilty of reckless conduct in shooting a 22-year-old unarmed woman, Rekia Boyd, in the back of the head, because he shot intentionally into the crowd where she was.

People tend to do what’s expected of them, and expecting unrest can be seen as a kind of permission, a loosening of standards. A number of community leaders sure sounded like they were already apologizing, already permitting. That’s the reason sports championships often unleash violent mob behavior. People should be rejoicing, yet some see the victory as a suspension of the usual rules, a chance to act out however they please. It isn’t just a poor black thing: after one Bulls championship, I watched a gang of white suburbanites turn over a cab on Rush Street. They did it a) because the cab was there and b) because the cops didn’t try to stop them.

Which brings up another factor possibly encouraging unrest. The charges being brought when they were is extraordinary timing, and it’s hard not to view it as Alvarez’s ham-handed attempt to quell trouble by throwing a cop under the bus. Though it might just as easily cause further violence. Because cops hate to see one of their brethren punished for anything, and typically respond with a collective sulk, pulling back and refusing to do their jobs out of the notion that nobody has their backs. “If every guy who makes a bad judgment call is charged with murder then why should we stick our necks out?” Small disturbances have a way of turning into big ones and if there is trouble, it won’t be surprising if sluggish police activity is also a contributing factor. Afterward, we’ll all pretend it was a surprise.