Mayor Rahm Emanuel on Thursday reversed his opposition to a possible U.S. Justice Department review of the Chicago Police Department's practices, the type of investigation that has led to federal court oversight and sweeping reforms in other troubled, big-city police departments throughout the country.

The about-face, coming a day after he called such an idea "misguided," allowed Emanuel to try to save face politically, as his new position put him in line with Illinois Attorney General Lisa Madigan and Democratic presidential front-runner Hillary Clinton, both of whom already had called for the Justice Department to act. Illinois' senior U.S. Sen. Dick Durbin and Cook County State's Attorney Anita Alvarez quickly followed suit Thursday, and the White House and Justice Department declined to comment on the prospects of a probe.

Chicago Mayor Rahm Emanuel backpedaled Wednesday on his opposition to a possible justice department review of the city's police department. Dec. 3, 2015. (WGN-TV) Chicago Mayor Rahm Emanuel backpedaled Wednesday on his opposition to a possible justice department review of the city's police department. Dec. 3, 2015. (WGN-TV) SEE MORE VIDEOS

Emanuel's decision to "welcome the engagement of the Justice Department" comes with a set of political pros and cons for the mayor, however.

On one hand, ending up with federal investigators and a judge driving change in the department would partially insulate Emanuel from rankling the city's 10,000 police officers, some of whom might be resistant to changes and all of whom live in the city, belong to an influential union and vote. On the other hand, sitting at the helm of a City Hall where a federal eye is needed to ensure proper conduct from cops could leave Emanuel looking like an ineffectual leader unable to deliver changes in a police department with a long history of excessive force and corruption.

Still, even if the Justice Department launches a probe, it could take months to reach conclusions and years if it finds changes are warranted. And there's the added wrinkle of the ongoing criminal investigation that the Chicago U.S. attorney and FBI office are conducting.

The calls for Washington intervention have come amid the fallout of Emanuel releasing a police dashboard camera video of the October 2014 Laquan McDonald shooting, which shows the African-American teenager getting shot repeatedly as he walked away from a white police officer.

A Cook County judge ruled Emanuel had violated state open records laws by not publicly releasing the video and ordered him to do so. Hours before Emanuel released the video last week — 13 months after the shooting — Alvarez charged Officer Jason Van Dyke with murder in the case, alleging he shot McDonald 16 times, many of the bullets striking the teen as he lay in the middle of a stretch of South Pulaski Road.

The police department said McDonald was shot after continuing to approach officers, while a police union spokesman said McDonald lunged at officers with a knife. The video later showed that not to be the case, which has contributed to widespread accusations of a cover-up.

A civil rights investigation by the U.S. Justice Department would not be limited to the McDonald case and would represent a much broader and deeper review of the Police Department's practices in the use of deadly and excessive force and how those cases are reported and investigated.

In many cases, such investigations result in a federal consent decree, where the Justice Department and the municipality reach an accord on how to right the Police Department's wrongs and a federal judge oversees the implementation of those changes and appoints a monitor to handle the day-to-day aspects.

The more deeply rooted a police department's dysfunction, the more likely it is to take the power of a consent decree to fix it, said Merrick Bobb, a police practices expert who serves as a federal monitor in Seattle's consent decree and has consulted in Chicago over police stops.

"When they are experiencing deep troubles and it's an issue of culture and generations being trained in a certain way," Bobb said, "the more deeply ingrained that culture is (and) the harder it is to reform without the hammer of the consent decree."

Political backpedal

While Alvarez has charged Van Dyke with murder in the McDonald shooting, the federal investigation into the shooting and circumstances surrounding remains ongoing, officials have confirmed.

Within a month of the shooting, Alvarez notified federal authorities, and a joint state and federal investigation was launched.

Witnesses have been brought before a federal grand jury, including the district manager of a Burger King restaurant who recently told the Tribune he testified that several police officers demanded to see the establishment's password-protected surveillance video immediately after the shooting. When they left almost two hours later, the video had an 86-minute gap that included when McDonald was shot, the manager said.

Alvarez and former police Superintendent Garry McCarthy, who Emanuel fired Tuesday, have said they found no evidence the video was tampered with.

Federal officials previously have prosecuted Chicago police for allegations they covered up fellow officers' behavior. The first time it happened was in 2003, when Edgar Placencio and Ruben Oliveras were convicted on criminal civil rights charges for covering up that corrupt fellow officers had stolen cocaine and then planted some of the drugs on an innocent man.

Talk of a separate Justice Department review in Chicago publicly surfaced Tuesday when Madigan wrote a letter to her federal counterpart, U.S. Attorney General Loretta Lynch, requesting a civil rights investigation into the Police Department's use of deadly force and the adequacy of its reviews of such cases.

On Wednesday morning, Emanuel said a wider probe would be "misguided" and suggested the focus remain on the ongoing criminal investigation into the McDonald shooting by U.S. Attorney Zachary Fardon and the FBI. But later Wednesday, Clinton sided with Madigan, with a spokesman saying the presidential candidate was "deeply troubled" by the McDonald shooting, adding that "given the gravity of this tragic situation, she supports a full review by the Department of Justice."

By Thursday morning, a full 24 hours after Emanuel resisted a Justice Department review, the mayor changed his tune and released a statement.

"I want to be clear that the city welcomes engagement by the Department of Justice when it comes to looking at the systemic issues embedded in CPD," said Emanuel, who made similar comments to reporters later as Google opened its new West Loop office. "As it relates to a longer-term review of our police department and efforts to improve police accountability, I am open to anything that will help give us answers and restore the trust that is critical to our public safety efforts."