It would be embarrassing for any police department, but for Chicago - which already withstood the humiliation once - it means much more. Especially now.
As bright as the media spotlight has shone on the department in the past, it will only get brighter because Chicago is the hometown of the next president of the United States and the city is vying for the 2016 Olympics.
It's unclear whether Anthony Abbate, the officer charged in the beating, will stand trial - it was supposed to begin Tuesday but has been delayed - or if the case will end with a plea bargain. A judge's gag order has prevented anyone from talking publicly about the case.
"I have to think it is important to get past (the case) not only from a PR standpoint, but Abbate has for the last two years defined what the department is," said Daniel P. Smith, author of "On the Job: Behind the Stars of the Chicago Police Department."
"So many officers do their job the right way but Abbate has defined who they are (and) I know for a fact many of them want it all erased."
Chicago officials already have set about to change the police department's image, starting 11 months ago, when they hired a new police superintendent, Jodi Weis, the former head of the FBI's Philadelphia office.
Police officers know that what they do is being watched like never before — starting on election night, when a quarter million people descended on Grant Park to be part of President-elect Barack Obama's historic victory.
"I talked to two sergeants who had their teams down there and one told his guys the eyes of the whole world are on (the park)," said Sgt. John Pallohusky, president of the police sergeants union.
It was the same message from the other sergeant. "He told his team, 'Do your part, show the world this is what we do,'" said Pallohusky.
Under the watchful eye of police, the scene at the park was peaceful. Department spokeswoman Monique Bond said that, despite the massive crowd, officers made fewer arrests than a typical Tuesday night.
That wasn't lost on observers, especially those who know the same park 40 years ago the world watched billy club-swinging police wading into crowds of protesters at the 1968 Democratic National Convention.
"It was a commercial for the city," said A.D. Frazier, the chief operating officer of the Olympic Games in Atlanta. "The fact that it went off flawlessly will stand out as a plus in everyone's mind who votes for an Olympic city."
Even so, Smith said, that scene will be hard-pressed to compete with the surveillance video from the night Abbate allegedly beat the bartender in February 2007 after she refused to serve him more drinks.
"All we see is the Abbate tape rolling over in our heads and we forget the absolute (great) job they did out there," he said.
It remains to be seen whether the Abbate case generates as much angst for the department as that of Jon Burge, the former commander of a unit that allegedly tortured black suspects decades ago.
Burge long has been a source of anger in Chicago, as politicians, community activists and others have complained that he remained free, living in retirement in Florida, while men they say were innocent and confessed only after being tortured remained in prison.
It was not until this year that Burge was charged by federal authorities with lying under oath when he denied participating in torture.
"Burge has haunted them for years," said Wesley Skogan, a Northwestern University political scientist who has studied the department extensively. "The Abbate case is difficult (and) because we've all seen the tape 10 times, it will linger longer in the public imagination."
Skogan said that how long Abbate casts a shadow on the department may depend on what attorneys are doing behind the scenes, and whether Abbate walks into court and pleads guilty or goes ahead with a trial.
"If there is a plea settlement as time gets really close, that might take the wind out of the sails," he said.
But, he added, even if that happens, "It could linger like O.J. (Simpson) or go away very quickly."
Bond, the police spokeswoman, would not specifically discuss the Abbate case. But Craig Futterman, a University of Chicago law professor who has studied the department, said it's clear why Weis publicly denounced Abbate and recommended firing him.
"By making an example of him they're saying this is a new day, we don't tolerate this stuff in Chicago," he said.
But he wonders if the firing was little more than a public relations ploy.
"My fear is that the underlying issues that allowed Abbate to do what he did ... haven't been addressed," he said. "As much as they want to say, 'this is a new day' ... is this really true?"