The Law Enforcement Leaders to Reduce Crime & Incarceration sent a letter to Sessions and Trump on Wednesday urging them not to return the “lock ‘em up” crime-fighting policies of the 1980s and 1990s and not to waste resources on low-level drug offenders.

The law enforcement leaders stated in the letter crime had been steadily declining across America for a quarter-century, and added the decline is a result of smarter policing and more careful prosecution.

“The measure isn’t how many people we put in jail,” Ronal Serpas, former superintendent of the New Orleans police and the founder of the Law Enforcement Leaders group said. “The measure is whether the right people are put in jail. And that’s the people we’re afraid of, not the people we’re mad at.”

Several police chiefs from Houston, San Francisco, Detroit and the District of Columbia joined Serpas in the support of a recent criminal justice reform bill that would reduce mandatory minimum sentences for low-level drug offenders, eliminate “three-strike” provisions and give judges greater sentencing discretion for certain low-level crimes. However, Sessions opposed the bill.

Manhattan district attorney Cyrus Vance was in support of the bill and said the message to the president is very clear.

“When arresting or prosecuting a case, authorities must ask two questions: Does it make us safer, and is it fair?”

The letter also asked for increased resources for mental health and drug treatment, noting “Republican governors have made treatment programs a centerpiece of their public safety efforts,” and calls for prioritizing federal resources on violent crime.

In addition, the letter aims to change the landscape in criminal justice. According to Richard Stanek, sheriff of Hennepin County, Minn., local courts need to be more involved and police and sheriffs need to be operating and arresting 24 hours a day.

“Forty hours a week isn’t good enough,” Stanek said. “When residents are subject to arrest 24/7.”

Houston Police Chief Art Acevedo said it was also time to revive a conversation around gun control. “If we’re really interested in impacting violent crime,” he said. “Let’s have some gun sense.”

As crime steadily declined nationwide, Acevedo said the current strategies have worked so far, but according to Serpas, it is also time to make changes as society evolves and people get smarter.