One man was gunned down on New Year’s Eve. Another was shot three times in the back as he ran away.

Both men were unarmed. Both were men of color. And both were killed, just seven months apart, by rookie Oakland Police Officer Hector Jimenez.

Jimenez was fired after the second shooting, one that the city paid $650,000 to settle a wrongful death lawsuit.

Yet just three years later, in 2011, Jimenez was back in uniform, reinstated with full back pay and benefits. He’d challenged his termination, appealing the decision to an independent arbitrator who would have final say over his fate at the department.

The arbitrator found that Jimenez had not violated department policy and concluded that the city should not have fired him. The dead man’s family was dismayed, civil rights activists outraged. Three years later, after an arbitrator reinstated another Oakland officer who was fired for having heaved a tear gas grenade into a crowd of protesters1 tending to an injured demonstrator, a federal judge cited both cases2 when he ordered an investigation3 into why Oakland police officers kept seeming to escape discipline and accountability, raising broad questions about the city’s management of arbitration cases.

"There are a lot of city attorneys and county  attorneys who deal with all sorts of stuff—landuse, contracts—and don't know squat about police disciplinary matters." Arnold Zack, Former President of the National Academy of Arbitrators and a Lecturer at Harvard Law School

From 2010 to 2015, arbitrators in Oakland had upheld just seven of 26 disciplinary actions, the inquiry found. And that city wasn’t alone. In another investigation in Philadelphia, arbitrators were found to have reinstated 19 of 26 officers fired between 2008 and 2014.

Arbitration is a common clause in union contracts—both for the nation’s 18,000 some-odd police departments and for organized labor at large. It’s a speedier and less costly alternative to lawsuits, and the system is generally seen by both unions and management as an effective way to resolve disputes.

Yet as fatal shootings by police have inflamed a nationwide debate about race, bias, police, and accountability, some civil rights activists and commentators have said the arbitration system has failed by too often allowing bad officers back on the force.

“In theory, due process before a neutral arbiter could even protect blue whistleblowers from wrongful termination. But in practice, too many cops who needlessly kill people, use excessive force, or otherwise abuse their authority are getting reprieves from termination,” said a report in The Atlantic4 in the wake of the 2014 protests in Ferguson, Missouri, its headline declaring “How Police Unions and Arbitrators Keep Abusive Cops on the Street.”

Arbitrators in the U.S. have eased or reversed discipline in favor of police officers in about 60 percent of cases since the 1980s, according to an informal tally by attorney Will Aitchison, who represents police unions and is director of the Labor Relations Information System, which offers training sessions and seminars and monitors labor trends.

However, he and others emphasize, the picture is far more complicated than that number suggests.

In most police departments with union contracts that permit arbitration, the union—not the officer—decides whether to appeal a reprimand, a suspension, or any other kind of discipline to an arbitrator. One notable exception is California, where individual employees, not their unions, make the call. As a result, arbitration—which is less expensive than a lawsuit but still not cheap—is exceedingly rare. A single arbitration can cost anywhere from $12,000 to $30,000, and that’s without expert witnesses or complicated allegations.

“Police unions are not careless in their decision-making. They want a case where there’s a reasonable chance of prevailing,” Aitchison says.

In 34 years of working with the Portland Police Association, which represented about 950 members in Oregon, for example, Aitchison handled just seven arbitrations out of an estimated 3,000 disciplinary actions handed down by lieutenants, captains, and chiefs.

But what’s the explanation for the most egregious cases, when truly “bad cops”—those who lie or are reckless or merely incompetent are handed back their guns and badges? The investigation in Oakland blamed not the arbitrators, but the city and the police department.

The department’s policies were “vague or inconsistent,” and the agency’s leadership “did not make it a priority to fix the system,” despite repeated criticism by arbitrators, the report found. Internal investigations were often “inadequate.” And the city attorney’s office, responsible for arguing to uphold the discipline in question, regularly “demonstrated neglect and indifference” by blowing crucial deadlines and “waiting until the last minute” to prepare or assign cases to attorneys. Those factors caused the city to lose arbitrations “time and again,” the cases undermined by flimsy arguments and evidence submitted too late to be allowed at all.

“Arbitrators follow due process as closely as the judicial standard,” says arbitrator Arnold Zack, former president of the National Academy of Arbitrators and a lecturer at Harvard Law School. “It is more important to have the process operating properly, even at the price of an inequity in a particular case. That overrides the bad apples.”

Unions, however, have helped make the process more complicated, lobbying for state bills that have established special labor protections for law enforcement that effectively set traps for city attorneys who not only may not specialize in labor law but haven’t pored over the sometimes Byzantine rules for police officers.

"Police unions are not careless in their decision-making. They want a case where there’s a reasonable chance of prevailing." Will Aitchison, Attorney Representing Police Unions and Director of the Labor Relations Information System

In California, for example, the Public Safety Officers Procedural Bill of Rights Act bars police supervisors from questioning any officer suspected of misconduct without first telling that officer he’s being investigated. That may sound straightforward, but imagine there’s been an altercation involving an officer, and a man is in handcuffs. When a sergeant gets to the scene, the sergeant can ask the officer, “What happened?” But if the sergeant were to get to the scene, and the person in custody began yelling that the officer beat him after he was handcuffed, the sergeant may no longer be allowed to ask the officer simply, “What happened?” Instead, the sergeant has to realize—amid the yelling and anything else happening—that the question may now have to be phrased another way to tell the officer upfront there’s been an accusation. “This guy says you beat him. Want to tell me what happened?”

“There are a lot of city attorneys and county attorneys who deal with all sorts of stuff—land-use, contracts—and don’t know squat about police disciplinary matters because that’s not what they deal with on a regular basis,” says attorney Martin Mayer who specializes in advising law enforcement as a partner at Jones & Mayer, a public sector law firm in California. “And on the other side are guys like Rocky Lucia, who know this stuff cold because that’s what they do.” He was referring to one of the best-known police union attorneys in the country, a partner at Rains Lucia Stern, which itself is one of the largest law firms in the nation to represent police officers.

Lucia notes that the rigid, paramilitary work environment in which police work takes place grants great authority to superiors and that arbitration protects individual officers from retribution or capricious discipline. It’s a process he insists is objective: both sides are presented with a list of five or seven arbitrators, and they take turns striking one at a time, working their way until there’s one left.

“It isn’t slanted in favor of anybody,” Lucia says. “In some places the cops get disciplined and fired without much due process, and that’s what arbitration is: due process.”

In one study of public-sector arbitration in Minnesota, arbitrators sided with employers in more than half of the 2,055 cases from 1982 to 2005. But even with every regulation upheld and each deadline met, some outcomes may still seem inexplicable, whether in arbitration or in court.

“Just picking up a newspaper and looking at the results, you would say, ʻHow did that happen?’” Aitchison says. “You will find aberrations with any system of justice.”