Police unions have helped shield officers from accountability. Now they’re facing unprecedented backlash

A demonstrator holds her hands up while she kneels in front of the Police at the Anaheim City Hall on June 1, 2020 in Anaheim, California, during a peaceful protest over the death of George Floyd. - Major US cities -- convulsed by protests, clashes with police and looting since the death in Minneapolis police custody of George Floyd a week ago -- braced Monday for another night of unrest. More than 40 cities have imposed curfews after consecutive nights of tension that included looting and the trashing of parked cars. (Photo by Apu GOMES / AFP) (Photo by APU GOMES/AFP via Getty Images)
A demonstrator holds her hands up while she kneels in front of the Police at the Anaheim City Hall on June 1, 2020 in Anaheim, California, during a peaceful protest over the death of George Floyd. - Major US cities -- convulsed by protests, clashes with police and looting since the death in Minneapolis police custody of George Floyd a week ago -- braced Monday for another night of unrest. More than 40 cities have imposed curfews after consecutive nights of tension that included looting and the trashing of parked cars. (Photo by Apu GOMES / AFP) (Photo by APU GOMES/AFP via Getty Images) (APU GOMES/AFP via Getty Images)

(CNN) –  One San Antonio police officer repeatedly used the n-word as he arrested a Black man for trespassing at a mall. Another told a man he could go free if he beat the officer in a fistfight. A third allegedly tried to give a homeless man a sandwich filled with dog feces.

All of them were fired by the police chief. And all of them were rehired after an arbitrator overturned their dismissals -- in a process laid out in the contract between the city and the powerful police union.

In more than four out of 10 of the cases in which arbitrators ruled on officer terminations over the last decade, those firings were overturned, according to data provided by the San Antonio police department.

"We've seen too many cases where the arbitrator has overturned the chief's decision when it's as clear as day that that officer accused of misconduct should no longer be on the force," Ron Nirenberg, the city's mayor, told CNN. "It's egregious."

San Antonio is hardly an exception: Around the country, police unions have played a decisive role in shaping department policies and shielding bad cops from accountability, experts say.

Now, as protests over the police killing of George Floyd have refocused national attention on police misconduct, unions representing officers are facing a wave of new scrutiny and an unprecedented political backlash.

More than 85% of police contracts in major cities around the country include language limiting oversight or discipline of officers, according to an analysis by Campaign Zero, a criminal justice reform advocacy group.

Often negotiated behind closed doors, contracts in some cases are approved by local politicians whose campaigns have been bankrolled by the same unions they're dealing with.