A new report on prisons and the criminal justice system in the U.S. found that mass incarceration is no longer as effective in reducing crime and rehabilitating inmates as supporters of tough-on-crime policies had hoped. The Congressional Research Service, a nonpartisan legislative agency of the U.S. Congress, said mass incarceration has “reached the point of diminishing returns.”

With approximately 1.5 million inmates locked up in state and federal prisons around the country in 2013, the CRS said new approaches are needed to reduce the imprisoned population. The policies should include new ways for officials to divert low-risk offenders from prisons, the agency said. “Because courts and correctional officials make decisions about who can safely be diverted from incarceration or granted early release, they may benefit from tools that can help in this process,” according to the report released last week.

In a 22-page report, the CRS said it found a dramatic increase in the number of people imprisoned “over the past three decades.” The tough-on-crime policies enacted by Congress in the 1990’s under President Bill Clinton’s administration saw non-violent drug offenders incarcerated at staggering rates, experts have said.  

“The incarceration rate increased from 179 per 100,000 people in 1983 to 478 per 100,000 in 2013," the report states. That increase has generated concerns among lawmakers and civil rights groups about the economic and social impacts of the nation's criminal justice system.

Reform of the criminal justice system has been part of local and national lawmakers’ political platform for more than a decade. New York City Mayor Bill de Blasio and members of his administration this month proposed a policy that increases the age that young offenders are sent to adult prisons in the city and in the state. New York officials recently agreed to reform a city jail, after the U.S. Department of Justice found a pattern and practice of abuse among jail guards and inmates against young offenders at Rikers Island Correctional Facility.

Democratic presidential candidate Hillary Clinton in April pivoted from stricter positions on criminal justice that she held as a U.S. senator, calling for an end to policies promoting mass incarceration that saw men of color disproportionately locked up for crimes committed by all races.