Illinois Attorney General Lisa Madigan, flanked by Chicago Mayor Rahm Emanuel, left, and Police Superintendent Eddie Johnson, announces a suit seeking federal court oversight over the Chicago police. (Rich Hein/ Chicago Sun Times/AP)

The Illinois attorney general said Tuesday that she has filed a lawsuit to bring about a court-enforceable agreement for police reform in Chicago because the Trump administration proved itself unwilling to press the matter.

Attorney General Lisa Madigan (D) said she would effectively take the place of the Justice Department in trying to negotiate a consent decree — which would include an independent monitor and be subject to a federal judge’s supervision — to force the troubled Chicago Police Department to make changes.

The Justice Department in the Obama administration had investigated the Chicago police and found that officers routinely used excessive force and violated residents’ constitutional rights. But before department lawyers could negotiate a court-enforceable agreement for changes, President Trump and his attorney general, Jeff Sessions, took office and the usual process was interrupted, Madigan said.

“The new administration at the Department of Justice has made it clear it will no longer seek a consent decree in Chicago,” Madigan said at a news conference to announce the lawsuit. She later added, “We are essentially stepping into the shoes of the Department of Justice, shoes that the DOJ has abandoned at this point.”

The lawsuit relies largely on the Justice Department’s findings and asks a federal judge to intervene.

In a statement, Justice Department spokesman Ian Prior said policing was “first and foremost a matter of local responsibility” and offered a circumspect assessment of Madigan’s lawsuit.

“If the City and State can put in place policies and practices to ensure constitutional, proactive policing that actually serves to reduce Chicago’s rampant violent crime problems, that would be a positive step,” he said. “However, we have said repeatedly that we will not agree to or support any measure that will endanger the lives of Chicago’s residents or law enforcement by eroding the rule of law or by failing to properly address violent crime in Chicago. We will continue to work with the city to meet those goals.”

Chicago Mayor Rahm Emanuel (D), who appeared with Madigan at the news conference and indicated that he supported the lawsuit, said that he had been talking with the Trump administration about implementing changes outside of court but that the White House seemed to have abandoned that effort.

“It became clear that they are disinterested in reform, that the Trump administration wasn’t even willing to pursue the concept they proposed themselves,” Emanuel said.

The Obama administration had been aggressive in pursuing court-enforceable reform agreements with police departments across the country and, in its waning days, took steps to put Chicago on the path to one.

The city department’s troubles have been well publicized. On Monday, an officer was convicted of civil rights violations for an incident in which he was caught on video opening fire into a car full of teenagers. The Justice Department in January had issued a blistering 164-page report on the Chicago police as a whole, outlining how officers in a city struggling with gun violence lacked appropriate training and supervision, failed to adequately investigate misconduct and violated residents’ civil rights.

If the administration had not changed hands, the report would probably have put the Chicago department on the path toward a legal agreement that would have mandated reforms. But Sessions, a longtime critic of such agreements, ordered Justice Department officials to review the pacts with troubled police forces nationwide, saying it was necessary to ensure that the agreements did not work against the Trump administration’s goals of promoting officer safety and morale while fighting violent crime. The Justice Department tried to delay approval of an agreement in Baltimore, although a judge signed off on it anyway, calling the need for oversight “urgent.” The agreements can be costly and are not always welcomed by officers.

Chicago’s police chief said Tuesday that the department began implementing reforms on its own. The city also had been talking about a solution that would not necessitate court involvement.

But Emanuel said the Trump administration backed off from even that alternative. And Madigan said she felt that a court-enforceable agreement — which would probably come with deadlines, financial commitments and an independent monitor — was the “only way to achieve real and lasting reform.”

Vanita Gupta, now president and chief executive of the Leadership Conference on Civil and Human Rights and the head of the Justice Department’s Civil Rights Division during the Chicago investigation, said she welcomed Madigan’s suit.

“Everyone deserves a police department that will keep them safe, consistent with the protections our Constitution demands,” Gupta said in a statement. “Where Attorney General Sessions refuses to act, we hope that other state and local governments will follow Illinois’ example and step in to the breach.”

Earlier this month, the city of Chicago sued the Justice Department in a separate case over the Trump administration’s plan to withhold federal public-safety grants to jurisdictions with “sanctuary city” policies. The city has long drawn the president’s attention for its high levels of violence.