After a year-long investigation into the Chicago Police Department, the U.S. Department of Justice today released a 164-page report detailing its findings.

What is the most important takeaway from this report?

The detailed nature of the report is unprecedented. It describes dozens of cringe-worthy incidents in which police in Chicago abused their power, even killing civilians, without being disciplined—sometimes with the complicity of an investigator. It details how officers feel unsupported by the department and often lack access to counseling, even when they seek it out. It shows how disrespect, especially against young people of color, has created a culture of mistrust that makes both officers and civilians less safe.

But more important, the report ties all these individual incidents together and shows how the problems are caused by the police department and the city as a whole, through inadequate training and support, lack of oversight and transparency, and a culture of impunity. Though it praises the majority of the department's officers and acknowledges the major challenges officers face on the job, the report nonetheless says it's essential to make structural changes in order to improve public safety in Chicago.

In short, the Justice Department found that "Chicago must undergo broad, fundamental reform to restore trust [between civilians and officers]," which federal officials said would both improve the department's ability to solve and prevent violent crime, as well as improve officer morale.

Is Chicago required to do anything after this report?

No. But Attorney General Loretta Lynch, who heads the Justice Department, said this morning that the city signed an "agreement in principle" to work with federal officials on a consent decree, a legally binding document that would require certain reforms with the oversight of a federal judge. Consent decrees that follow Justice Department investigations can take months, if not years, to finalize and cost millions of dollars to enforce.

How will the incoming Trump administration affect this whole thing?

There's the rub. If the new administration doesn't want to work with Chicago on a consent decree, the "agreement in principle" could mean nothing. At this morning's announcement, Emanuel declined to speculate about the incoming administration's treatment of the report.

President-elect Donald Trump's nominee for attorney general, Senator Jeff Sessions, has previously stated that he doesn't believe the Justice Department should be investigating entire police departments. Earlier this month, Sessions told Senator Dick Durbin that he was "not prepared to commit" to following through on the Justice Department's recommendations, according to according to Politico.

Why was the Justice Department investigating Chicago police?

In November 2015, the city was forced to release a video showing police officer Jason Van Dyke shooting and killing 17-year-old Laquan McDonald. The dashcam video, which showed that McDonald was walking away from officers when he was killed, set off weeks of protests and nationwide outrage, leading to the resignation of Chicago's police superintendent. Shortly thereafter, the U.S. Department of Justice announced it would investigate whether the "patterns and practices" of the Chicago Police Department violated people's civil rights.

What's changed since that other damning report about Chicago Police last spring?

Since the mayor's Police Accountability Task Force released its own report in April, there has been some movement on reform. First, City Council passed an ordinance creating a new police oversight group, the Civilian Office of Police Accountability, as well as a city watchdog position to watch over it. The city has promised more transparency in relation to officer misconduct investigations, and committed to outfitting all officers with body-worn cameras by the end of the year. There have been changes in officer training, revised rules for when police can use force against civilians, and efforts to increase the force's diversity.

What went into compiling this report?

The Justice Department was granted access to all of Chicago's official police documents, including its misconduct complaint database and use of force reports in the last five years. Federal officials interviewed almost 400 city employees, including members of the police department and the Independent Police Review Authority, and conducted 60 ride-alongs with officers.

Federal officials also reached out to Chicago citizens, including over 90 community groups, family members of people killed by police officers, local researchers and lawyers, and more. They received nearly 600 contacts from residents and hosted several forums around the city requesting public feedback.

How much did it cost?

Crain's reports that the city of Chicago spent $3.8 million on consultants and lawyers to represent the city during the probe. That doesn't include how much it cost the federal government (Lynch says her department assembled the largest team ever for a civil rights probe), nor the time and efforts of police and city officials who participated in the process.

What were the main points?

The report focuses on seven areas:

• Use of Force: "CPD officers engage in a pattern or practice of using force, including deadly force, that is unreasonable. [These practices] unnecessarily endanger themselves and others and result in unnecessary and avoidable shootings and other uses of force." The report says that Chicago police use force that is both contradictory to Constitutional law as well as the department's own guidelines.
• Accountability: "The City does not investigate the majority of [police misconduct] cases it is required by law to investigate." The report says that "there is no meaningful, systemic accountability for officers … creat[ing] a culture in which officers expect to use force and not to be questioned about the need for or propriety of that use." Misconduct investigations are "frustrated by police officers' code of silence," and officers who lie or cover up misconduct and are not punished for doing so.
• Training and Supervision: "CPD's pattern of unlawful conduct is due in part to deficiencies in CPD's training and supervision," the report found, both in the police academy and in post-academy training. "Only one in six recruits came close to properly articulating the legal standard for use of force." It also found inadequate training for dealing with mental health situations, domestic violence, and young people. Plus: "CPD does not sufficiently encourage or facilitate supervisors to provide meaningful supervision to officers."
• Officer Wellness and Safety: Considering the high levels of stress and trauma of the job, "CPD needs to transform its officer support system so that officer wellness is an integral part of the Department's operations," the report says. The current employee-assistance program is much smaller than other police departments, and investigators found that internal culture/stigma often keeps officers from seeking help.
• Data Collection and Transparency: "Data that is collected and publicly reported by the City is incomplete, and at times, inaccurate," the report says. The department's data collection systems are fundamentally flawed, which makes it difficult for CPD to identify unlawful practices and contributes to the distrust between CPD and the public.
• Promotions: Despite several lawsuits and a recent high-profile cheating scandal, CPD's promotions system remains flawed. "CPD does not effectively communicate the details of its promotions process to the rank-and-file, and does not provide sufficient transparency following promotional decisional to allay officer concerns," the report says.
• Community/race RELATIONS: It's no surprise that community relations are incredibly tense, and Chicago's community policing program is woefully understaffed and underfunded. The report, more shockingly, found extreme abuse of power by police against communities of color: "CPD will take a young person to a rival gang neighborhood, and either leave the person there, or display the youth to rival members, immediately putting the life of that young person in jeopardy." The report substantiated accusations that activists and people of color have made for years, including that officers will illegally arrest or detain individuals in order to obtain information about gang activity or other crimes.