AFTER A Post investigation revealed that D.C. police had fatally shot more people per capita in the 1990s than officers in any other large municipal police department in the country, the U.S. Justice Department got involved, forging an agreement in 2001 that required the District to undertake certain reforms. Across the border in neighboring Maryland, the Prince George’s County Police Department was subject to federal court decrees after investigations revealed excessive police force and abuses in the use of police dogs. The result, both departments agree, was better training, modernized equipment and improved policies that have helped build community trust. Crime didn’t go up; it decreased.

We bring up the experiences of these two departments in light of the plans announced by Attorney General Jeff Sessions to review agreements reached by the Obama administration with a dozen or so troubled police departments as part of its mission “to ensure public safety.” Embedded in this unprecedented review is the notion that trying to correct patterns of police misconduct is somehow at odds with public safety. There is nothing incompatible between good policing and respecting people’s civil rights, nor between respecting people’s civil rights and respecting the difficult work good police officers do. It is troubling that the Trump administration seems willing — even eager — to abandon the government’s role in ensuring that all interests are protected.

A March 31 memorandum from Mr. Sessions made public Monday directs his top staff to review reform agreements reached with police departments that were found to have routinely violated the civil rights of individuals. Minorities, notably African Americans, are most often singled out for unfair and abusive treatment, ranging from frivolous stops and arrests to use of excessive and deadly force. While it may be hard for the Justice Department to undo agreements authorized by courts and with independent monitors in place, reforms are at risk in cities where a judge has yet to approve a decree (Baltimore) or where negotiations are still underway (Chicago).

Encouragingly, officials in both Baltimore and Chicago said they want to move forward with plans for police reforms no matter what the federal government does. Absence of a court decree might make it more difficult to receive the funding needed for timely reform. Baltimore Police Commissioner Kevin Davis called the request by Justice officials for a 90-day delay in court proceedings over the agreement “a punch in the gut” and said, “We have to continue to stress the necessity of constitutional policing in Baltimore and break the culture of zero-tolerance policing brought to the city many years ago.” Mr. Davis knows firsthand the benefits of police reforms enacted under court decrees from his time on the police force in Prince George’s.

It is that kind of informed experience — rather than vacuous “tough on crime” slogans — that should guide the country’s highest law enforcement officer. In signaling the Trump administration’s lack of interest in investigating local police departments and helping them improve, Mr. Sessions sends a message that will end up hurting both police and the communities they protect.