More than a hundred of the nation's top police chiefs and prosecutors are joining forces today to launch a new effort to cut the number of people in prison. The new coalition of 120 heavyweights, called Law Enforcement Leaders to Reduce Crime and Incarceration, is based on one big idea: Putting too many people behind bars doesn't keep the public safe.

"Our experience has been, and in some ways it's counterintuitive, that you really can reduce crime and incarceration at the same time," said Ronal Serpas, co-chair of the group.

Serpas spent about 35 years in law enforcement, in jobs that took him from New Orleans to Washington state to Nashville. He told NPR he's come to believe that the justice system should conserve resources to handle the most serious and violent offenders. In too many cases, Serpas said, that doesn't happen now.

"Our officers are losing all day long on arrest reports and at lockups dropping off prisoners — it's for low-level offenders who pose no threat to the community, are posing very little to no threat for recidivism, and overwhelmingly are just folks who have mental health or drug addiction problems that there's no place else for them to go," he said.

Serpas said he and other members of the group will be speaking out and trying to change state and federal laws. Their goals include cutting tough mandatory minimum prison terms, opening up more alternatives to incarceration like mental health and sobriety centers, and fostering better relationships with communities of color.

Experts in criminal justice policy said the new group marks a big turnaround from the lock 'em up practices of 20 years ago.

"We have been seeing now an incredible shift in the politics of crime and punishment," said Inimai Chettiar, who directs the justice program at the Brennan Center for Justice.

Chettiar said over the past few years, police and presidential candidates from both political parties have embraced calls for change. Members of the new group are getting support from the White House, too. They're scheduled to meet there to discuss their ideas Thursday.

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