In nearly two decades with the Minneapolis Police Department, Derek Chauvin faced at least 17 misconduct complaints, none of which derailed his career.Over the years, civilian review boards came and went, and a federal review recommended that the troubled department improve its system for flagging problematic officers.All the while, Chauvin tussled with a man before firing two shots, critically wounding him. He was admonished for using derogatory language and a demeaning tone with the public. He was named in a brutality lawsuit. But he received no discipline other than two letters of reprimand.It was not until Chauvin, 44, was seen in a video with his left knee pinned to the neck of a black man, prone for nearly nine minutes and pleading for relief, that the officer, who is white, was suspended, fired and then, on Friday, charged with murder.His case is not unusual. Critics say the department, despite its long history of accusations of abuse, never fully put in place federal recommendations to overhaul the way in which it tracks complaints and punishes officers -- with just a handful over the years facing termination or severe punishment.Even as outrage has mounted over deaths at the hands of the police, it remains notoriously difficult in the United States to hold officers accountable, in part because of the political clout of police unions, the reluctance of investigators, prosecutors and juries to second-guess an officer's split-second decision and the wide latitude the law gives police officers to use force.Police departments themselves have often resisted civilian review or dragged their feet when it comes to overhauling officer disciplinary practices. And even change-oriented police chiefs in cities like Baltimore and Philadelphia -- which over the last few years have been the sites of high-profile deaths of black men by white officers -- have struggled to punish or remove bad actors.The challenge has played out against and reinforced racial divisions in America, with largely white police forces accused of bias and brutality in black, Latino and other minority communities. Floyd's death came just weeks after Ahmaud Arbery, a black man in southeast Georgia, was pursued by three white men and killed, and after Breonna Taylor, a black woman, was fatally shot by police in Kentucky.Their deaths have unleashed a wave of tremendous protests across the country, extending far beyond Minneapolis on Friday, with protesters destroying police vehicles in Atlanta and New York, and blocking major streets in San Jose, California, and Detroit -- all cities that have wrestled with accusations of police misconduct.In Minneapolis, authorities took quick action against Chauvin and three other officers involved in Floyd's death, firing them one day after a graphic video emerged of the encounter. But that does not mean the officers are gone for good. Public employees can appeal their dismissals -- and in scores of cases across the country, the officers often win.The St. Paul Pioneer Press analyzed five years' worth of such appeals and found that between 2014 and 2019, Minnesota arbitrators -- a group that hears a range of public service complaints -- ruled in favor of terminated law enforcement and correction officers 46% of the time, reinstating them.In three terminations involving law enforcement officers that were reviewed this year, two were overturned.Dave Bicking, a board member of Communities United Against Police Brutality, a Twin Cities advocacy group, said many disciplinary actions are overturned because they are compared to previous cases, making it hard for departments to reverse a history of leniency or respond to changing community expectations."Because the department has never disciplined anybody, for anything, when they try to do it now, it's considered arbitrary and capricious," he said.Bicking described a history of attempts to clean up the Minneapolis police force, which is overwhelmingly white and for decades has faced accusations of excessive force, especially by African American residents.In Minneapolis, a city heralded for its progressive politics, pretty parks and robust employment, the racial divide runs deep. From education to wages, African Americans are at a disadvantage, graduating at much lower rates and earning about one-third less than white residents.And while black residents account for about 20% of the city's population, police department data shows they are more likely to be pulled over, arrested and have force used against them than white residents. And black people accounted for more than 60% of the victims in Minneapolis police shootings from late 2009 through May 2019, data shows.When there was a civilian review board to field the complaints, it would recommend discipline, but the police chief at the time would often refuse to impose it, said Bicking, who served on the board.Across the country, civilian review boards -- generally composed of members of the public -- have been notoriously weak. They gather accounts, but cannot enforce any recommendations.In 2008, the Police Executive Research Forum issued a report on disciplinary procedures in Minneapolis, at the department's behest. It recommended resetting expectations with a new, matrix specifying violations and consequences. But Bicking said the department soon fell back to old ways.In 2012, the civilian board in Minneapolis was replaced by an agency called the Office of Police Conduct Review. Since then, more than 2,600 misconduct complaints have been filed by members of the public, but only 12 have resulted in an officer being disciplined, Bicking said. The most severe censure has been a 40-hour suspension, he said."When we say there's a failure of accountability and discipline in this city, it is extreme," he said, adding that the City Council had promised to review the board, but has yet to do so.Any member of the public may file a complaint, and experts say that the volume of complaints may reflect a host of issues other than actual misconduct, such as the level of trust the community has in its department.Maria Haberfeld, an expert on police training and discipline at the John Jay College of Criminal Justice in New York, said Chauvin's complaint tally averaged to less than one a year, not unusual for a street officer, and probably not high enough to trigger an early warning system.But the patchwork nature of the city's disciplinary tracking was clear in Chauvin's case. The city released an Internal Affairs summary with 17 complaints. The city's police conduct database listed only 12, some of which did not appear to be included in the summary, and Communities United Against Police Brutality, which also maintains a database, had yet more complaint numbers not included in the first two sources.The nature of the complaints was not disclosed.Chauvin was one of four officers who responded to a call on Memorial Day that a man had tried buying cigarettes with a fake $20 bill. The other officers, identified by authorities as Thomas Lane, Tou Thao and J. Alexander Kueng, also were fired and remain under investigation. The county attorney said he expected to bring charges, but offered no further details.Neither Lane nor Kueng had misconduct complaints filed against them, according to the department. But Thao faced six in his career and also was the subject of a lawsuit that claimed he and another officer punched, kicked and kneed an African American man, leaving the man with broken teeth and bruises.According to the lawsuit, the incident occurred in early October 2014, when the man, Lamar Ferguson, then 26, was walking home with his girlfriend. A police car approached and Ferguson's girlfriend kept walking.The lawsuit states that Thao asked Ferguson to put his hands on the roof of the car and then handcuffed him. The complaint said that the other officer then "falsely stated there was a warrant out" for Ferguson's arrest regarding an incident involving family members. Ferguson told the officers he had no information to tell them.During the encounter, "Officer Thao then threw" Ferguson, "handcuffed, to the ground and began hitting him."Patrick R. Burns, one of the lawyers who represented Ferguson, said in an interview Friday that the city settled the case for $25,000."What I learned from that case and several others I have handled against the department is that some of the officers think they don't have to abide by their own training and rules when dealing with the public," he said.The head of the police union, Lt. Bob Kroll, is himself the subject of at least 29 complaints. Three resulted in discipline, The Star Tribune reported in 2015. Kroll was accused of using excessive force and racial slurs, in a case that was dismissed, and was named in a racial discrimination lawsuit brought in 2007 by several officers, including the man who is now the police chief.Teresa Nelson, legal director for the ACLU of Minnesota, said attempts by the city's police leaders to reform the department's culture have been undermined by Kroll, who she said downplays complaints and works to reinstate officers who are fired, no matter the reason.She said that in a 2015 meeting after a fatal police shooting, Kroll told her that he views community complaints like fouls in basketball. "He told me, 'If you're not getting any fouls, you're not working hard enough,'" she said.Kroll did not return several messages seeking comment this week.Changing department policies and culture can take years, even when there is a will to do so.In 2009, the Minneapolis department instituted an Early Intervention System to track red flags such as misconduct allegations, vehicle pursuits, use of force and discharge of weapons. Such systems are supposed to identify "potential personnel problems" before they become threats to public trust or generate costly civil rights lawsuits.In a case similar to the death of Floyd, David Cornelius Smith, a black man with mental illness, died in 2010 after two officers trying to subdue him held him prone for nearly four minutes. The chief at the time defended the officers, and they were never disciplined, said Robert Bennett, a lawyer who represented Smith's family.In 2013, the police chief at the time, Janee Harteau, asked the Department of Justice to review the department's warning system. A federal report found that it had "systemic challenges" and questioned its ability to "create sustainable behavior change."Early warning systems are considered a key part of righting troubled departments, criminologists say. Most cities that have been found to have a pattern of civil rights violations and placed under a federal consent decree, or improvement plan, are required to have one.Harteau, who left the top post in the wake of a 2017 fatal police shooting, said she took many steps to reform the department, including training officers on implicit bias and mandating the use of body cameras. But the police union, she said, fought her at every turn.In 2016, the department updated its use of force policy to hold officers accountable for intervening if they see their fellow officers using excessive force, Nelson said.The new policy, made in the wake of previous fatal shootings, was part of an effort to reform police culture in the city."It's why you saw four officers fired," in Floyd's case, she said.It's not clear whether an improved early warning system would have flagged Chauvin, who also had been involved in at least three shootings in his career, or the other officers involved in Floyd's death. Departments choose from a number of bench marks, and from a range of responses when they are exceeded.Haberfeld, the training expert, said police departments will not change until they invest significantly more in recruitment and training, areas where the U.S. lags far behind other democracies.Otherwise, she said, "There is a scandal, there is a call for reform -- committees and commissions and nothing happens. Nothing."This article originally appeared in The New York Times.(C) 2020 The New York Times Company