President Barack Obama has vowed to push for criminal justice reform in his final months in office. But analysts say his Justice Department has already made a legacy-defining imprint on policing.Relying on a sweeping federal law drafted 22 years ago by then-Sen. Joe Biden, the Obama administration has pursued about two dozen civil rights inquiries into local police such as the one focused on the Baltimore Police Department to be released on Wednesday."This is the one tool that the Department of Justice has been able to use to advance comprehensive police reform in some of our most troubled communities," said Kanya A. Bennett of the American Civil Liberties Union. "This is the one resource that does not rely on bipartisan agreement to get something accomplished."The long-awaited Justice Department report on Baltimore, which comes more than a year after the death of Freddie Gray from spinal injuries suffered in police custody set off riots in the city, concludes that officers routinely violated constitutional rights — an impact that fell disproportionately on black residents.Despite high-profile cases of African-Americans dying in interactions with police in Ferguson, Mo., New York and Chicago — and now deadly attacks on officers in Dallas and Baton Rouge — there has been little movement to advance criminal justice legislation in Congress. The issue has become further politicized by a presidential election in which Democrat Hillary Clinton and Republican Donald Trump are at odds over policing.That has left the administration with few options with which to deal with troubling questions about race and inequality that have grown more pronounced during Obama's second term.A White House task force on policing last year recommended better reporting of police-involved shootings, de-escalation training for officers and stronger relationships with communities, but those recommendations are not binding and do not address problems in individual police departments.It is not that the Obama administration has opened significantly more of the civil rights investigations — the number is roughly equivalent to those launched under the previous administration, according to a list of cases provided by the Justice Department — but rather how those inquiries are being closed.Under President George W. Bush, the Justice Department was more likely to rely on informal agreements to try to address systemic problems. Under Obama, the government is more likely to seek court intervention or monitoring by a third party.The stepped-up effort began with Labor Secretary Thomas E. Perez, who oversaw the Justice Department's civil rights division during Obama's first term. And it continues with the current head of the division, Vanita Gupta."There's no question that at this moment in time, police-community trust is one of the top not only civil rights issues, but domestic issues confronting the country right now, and communities all over the country," Gupta said in an interview.Authority for the federal investigations relies heavily on a 1994 law passed in the wake of the riots in Los Angeles after the police beating of black motorist Rodney King. Other provisions of the law, which was signed by President Bill Clinton, have been criticized by some for accelerating incarceration rates.Just how effective the effort has been remains open to debate. A half-dozen criminal justice analysts interviewed by The Baltimore Sun said that, on balance, the investigations and subsequent agreements likely have had an impact. That might be in part because their very creation is politically embarrassing for police and city officials."In general it's been successful with deeply troubled police departments — defined as departments that just seem to be unable to reform themselves," said Samuel Walker, a professor emeritus of criminal justice at the University of Nebraska, Omaha who has written several books on police accountability."It's not perfect. There's been some backsliding in some of those departments at a higher level in terms of understanding the basic requirements of professional and constitutional policing," he said.Others have been more openly critical of the investigations and the results. Heather Mac Donald, a fellow at the Manhattan Institute, has argued that court-ordered reforms are onerous and costly for police departments, and that the training — and specifically training intended to address racial biases — has little positive impact."It takes officers off the street," Mac Donald said. "It's a real tragedy for law enforcement."Criminal justice analysts often point to Cincinnati as a model for how federal investigations and pressure from outside groups can leave a lasting mark on a police department.Federal officials opened their inquiry there after the police shooting of 19-year-old Timothy Thomas, an unarmed black man, in 2001 sparked days of riots.The city and the federal government signed an agreement a year later that set up a formal process for citizen complaints and created a Citizen Complaint Authority that, with the City Council's approval, has power to subpoena police. A separate agreement with the ACLU required police to adopt a strategy to engage with the community before crime occurred.Citizen complaints about police in Cincinnati fell nearly 42 percent from 2005 to 2014, and the number of use-of-force incidents fell more than 69 percent from a peak in 2000, according to a report by the University of Cincinnati Institute of Crime Science.While the declines seem to indicate success, several criminal justice analysts caution that many factors beyond federal pressure can influence those numbers."This is an area that really is almost impervious to formal data analysis," said Robert Weisberg, co-director of the Stanford Criminal Justice Center. "It seems clear that it's been successful in cajoling settlements."Prince George's County was the subject of two civil rights investigations opened during the Clinton administration, including one that focused on excessive force and that resulted in a years-long monitoring of police practices.Several people involved with the effort said it ultimately changed the culture of the department. But many credited local rather than federal officials with the transformation."It was our vision at the time that cops could do this better than lawyers," said Joe Wolfinger, a former FBI agent and consultant who was brought in to monitor the progress in Prince George's County. "You can't make changes in a police department unless you have the cooperation of the department."June White Dillard, an attorney who led the Prince George's County chapter of the NAACP at the time, said she believed the impact of the Justice Department investigation was significant but acknowledged that it did not fix all the problems."We continually have to work on ways to make sure the bad apples don't have a big impact in the community," she said.Even more difficult to assess is whether the investigations have a deterrent effect on departments not directly under scrutiny.Gupta said agreements can show other police departments how to get ahead of problems before they become national news."Our agreements over the span of many years, I think, really do serve as blueprints for communities around the country that are confronting a lot of concerns around excessive use of force, discriminatory policing, kind of across a span of issues," Gupta said. "This is a body of work that is speaking to the moment in time that we're finding ourselves in."Baltimore Sun reporter Kevin Rector contributed to this article.john.fritze@baltsun.comtwitter.com/jfritze