By launching federal investigations into police departments in Minneapolis and Louisville, Attorney General Merrick Garland has sent a clear message to local law enforcement agencies that their relative impunity during the Trump administration is over.

Standing in front of an American flag, Garland framed his actions as the start of an effort to rebuild trust among marginalized communities and police. “We undertake this task with determination and urgency,” he said, “knowing that change cannot wait.”

But Garland also has set up a potential expectations gap with civil rights activists and liberal politicians who have warned the Biden administration that a mere return to Obama-era strategies to combat abusive policing is a recipe for failure and disappointment.

The mass social justice protests that swept through American cities last summer — following the police killing of George Floyd, a Black man, in Minneapolis — coalesced around a demand for a wholesale reimagining of law enforcement, including calls to dramatically defund police departments and significantly scale back the use of prison sentences for low-level offenders.

By those standards, Garland’s announcement that Justice Department lawyers will undertake sweeping “pattern or practice” investigations into the policies and culture of the Minneapolis and Louisville police is destined to fall well short, observers say, even if it does represent an extraordinary intervention of federal authority.

The Washington Post's Rick Noack goes inside a police training school in Oranienburg, Germany, to look at de-escalation training for officers there. (Alexa Juliana Ard, Rick Noack, Stefan Czimmek/The Washington Post)

Former Justice Department officials who oversaw such probes during the Obama administration cautioned that they are painstaking and time-consuming operations. It typically takes months to complete an investigation and years to carry out reforms under a court-approved “consent decree” settlement that usually includes an oversight monitor.

And although Garland aides have suggested that the investigations into Minneapolis and Louisville could produce a road map to guide other police departments to pursue reform on their own, those who have done such work sought to temper such conjecture.

“They absolutely need to manage expectations about what these federal investigations can achieve,” said Christy E. Lopez, who led more than a half-dozen Justice Department investigations into local police, including in Ferguson, Mo.; Chicago; New Orleans and Newark, amid public blowback over violent incidents akin to those last year in Minneapolis and Louisville.

Such efforts are valuable and can pay dividends, she said, but “it’s become very clear to me: I used to think federal investigations and consent decrees are all that’s needed and everything would be fine. The more I did work on it, the more I came to realize that consent decrees do not fix policing writ large and not entirely in any particular department.”

Ultimately, Lopez said, the Justice Department’s aim is to “address patterns of unlawful conduct. But there is a lot of really harmful policing that is perfectly legal under state, federal and local laws.”

The scale of the challenge is reflected in the numbers. There are an estimated 18,000 federal, state, county and local law enforcement agencies in the United States. During the eight years of the Obama administration, the Justice Department’s Civil Rights Division opened 25 investigations into local police and enforced 14 consent decrees.

Under President Donald Trump, the Justice Department effectively ended the practice. In 2018, then-Attorney General Jeff Sessions issued a memo that severely limited the ability of Justice Department lawyers to negotiate consent decrees, which he considered “dangerous” government overreach. The Trump administration dropped a settlement with Chicago that was negotiated after a White police officer fatally shot 17-year-old Laquan McDonald, who was Black, in 2014.

“I think the community is appropriately out of patience and does not need to be cautioned toward patience anymore,” said civil rights attorney S. Lee Merritt, who has represented families of Black people who died in police custody.

“The role of the federal government in officer-involved shootings and policing in general needs to take a leap forward. It’s not enough to do the policies of the past that have not worked,” said Merritt, who is running as a Democrat to unseat Texas’s Republican attorney general. “It’s great to see them do old things, but we want to see innovation coming out of DOJ.”

Experts said that most of the investigations have come in large, urban jurisdictions, where a greater percentage of police brutality and civil rights cases take place. But they said the Justice Department’s Special Litigation Section has limited resources to conduct the kind of expensive and exhaustive examinations that are required.

Officials said career lawyers from the Civil Rights Division already have been gathering information and meeting with community leaders and public officials in Minneapolis and Louisville. In both cities, the Justice Department is expected to hire a team of policy experts, including former police officials with experience in reform.

“If you’re trying to change the culture of policing, you’re going to affect Louisville and Minneapolis, but this can’t be your strategy for changing American policing,” said Chuck Wexler, executive director of the Police Executive Research Forum, which works with police leadership. “I’ve told the administration behind the scenes that it can’t simply be, ‘Let’s take the playbook from the Obama administration and apply it now.’ ”

Wexler’s group has chafed over the length of time federal monitors have spent overseeing reforms in some cities, which have lasted nearly a decade. The police departments in New Orleans, which negotiated a settlement with the Justice Department in 2013, and Seattle, which did so in 2012, are still under the oversight of court-appointed monitors.

In February, monitors in New Orleans, where the police department has adopted 200 new policies, released a report stating that the department “could and should have” made more progress in 2020. The monitors cited a pattern of unconstitutional searches starting in 2019, a finding that came after the department had been cited in 2018 for making major progress.

Also in February, District Court Judge James Robart in Seattle ruled that the department remains out of full compliance with the 2012 settlement. Robart ruled in 2019 that the department had reached compliance, but he reversed that decision after activists decried a new city contract with police that they said undercut many of the reforms.

Robart said the court is now reviewing tactics Seattle police used in response to demonstrators who took to city streets amid the social justice protests last summer.

“It is a tool that at best will produce marginal returns,” said Maurice Mitchell, the national director of the Working Families Party and a leader of the Movement for Black Lives coalition. “That’s not to say we do not use this tool, but we should not have any illusions that this tool is a panacea. I am concerned when there is news of investigations, or news of landing consent decrees, that we mark those up as successes. These are process points. We didn’t hit the streets because of processes. We want results.”

Justice Department leaders and Biden White House aides emphasized that they do not view the investigations as a strategy to use in isolation.

The Minneapolis Star Tribune reported last week that the department plans to ask a grand jury to indict former officer Derek Chauvin, who was found guilty on two murder charges and one for manslaughter in Floyd’s death, and three other former officers involved in the case on federal civil rights violations — a move that could signal a more aggressive federal approach to holding individual officers accountable. A Justice Department spokeswoman declined to comment on the matter.

Last week, in an address to a joint session of Congress, President Biden called on Senate Republicans to support the George Floyd Justice in Policing Act, which the House approved in March. The legislation would ban racial profiling, outlaw choke holds and no-knock warrants on the federal level, create a national police misconduct registry and make changes to qualified immunity, which has shielded officers from being held personally responsible for constitutional violations.

“The country supports this reform, and Congress should act,” Biden said. “With the plans outlined tonight, we have a real chance to root out systemic racism that plagues America and American lives in other ways.”

White House domestic policy adviser Susan Rice and senior adviser Cedric L. Richmond met Thursday with relatives of Floyd and several other Black men killed by police, in a discussion that grew emotional, according to Ben Crump, who represents the Floyd family.

Samuel Walker, an author who has studied policing and criminal justice, said criticism of consent decrees is misplaced, citing significant progress in some departments to reduce the use of force. He pointed to recent reports that no officer in the Newark police department fired a service weapon in all of 2020.

Walker said Justice officials in Democratic administrations have found ways to improve their investigations, based on past experiences, including working more closely with community leaders.

“Changing a police department and reducing the use of force and beginning to break down officer subculture — that’s an enormous task and takes a lot of time and a lot of effort,” Walker said. “The only way to deal with that is through a solid public education campaign to say: ‘Look, we just can’t snap our fingers and have this policy and that fixes things.’ That’s a fantasy.”