The California legislature has passed a bill that prevents juveniles 15 or younger from being transferred into adult court for any crime, a dramatic turnaround in a state that used to give wide discretion to prosecutors in seeking adult time for youths.

“California has shown us what is possible if you invest in youth and families in their communities,” said Marcy Mistrett, CEO of the Campaign for Youth Justice, which supported the bill. “From ending direct file, to adding adolescent development considerations to judicial hearings, to sentencing reform and jail removal — California has dropped incarceration rapidly while keeping crime low.”

The bill, Senate Bill 1391, has to return to the California Senate for a procedural vote. Supporters of it say Gov. Jerry Brown (D) is expected to sign the bill into law.

Currently in California, teens aged 14 and older who are charged with certain serious offenses can be sent to adult court for adjudication at the behest of a judge through a transfer hearing. Young teens charged with murder and some sexual offenses are automatically transferred to adult court.

If SB 1391 becomes law, all 14- and 15-year-olds charged with a crime would be handled in the juvenile justice system. Under no circumstances would anyone younger than age 16 be tried in adult court, even for murder charges.

“Cognitive science has proven that children and youth who commit crimes are very capable of change,” said State Sen. Ricardo Lara (D), the bill’s author, in an interview this summer with The Imprint. “Sending youth to an adult prison does not help our youth and does not make our communities any safer.”

The vast majority of youth transferred to adult court are 16- and 17-year-olds. In California, any youth who is incarcerated following an adult conviction is placed in a juvenile facility until they are adults.

In recent years, the average number of 14- and 15-year-old transfers was around 70. The total plummeted to 32 in 2016 after Proposition 57 ended the practice of allowing prosecutors to directly file charges on teens in adult court. That action must now be approved by a judge in California.

Supporters of SB 1391 argue that keeping 14- and 15-year-old offenders in the juvenile justice system will reduce recidivism rates and better rehabilitate and prepare youth for successful, productive re-entry into society.

These benefits are credited, in part, to the availability — and mandatory nature — of services such as education and counseling. But the other side of the coin is that keeping youth in the juvenile system protects them from the behaviors and personalities in adult prison.

“These youth are very young, very moldable,” said Israel Villa, a policy coordinator with the nonprofit MILPA Collective (short for Motivating Individual Leadership for Public Advancement), in an interview with The Imprint this summer. “Do we want these kids in a level four prison with the most violent offenders where they can be molded, utilized, often abused? Or do we want them in a juvenile facility amongst their peers with access to all these things to rehabilitate them?”

Opponents of the bill include the California Police Chiefs’ Association, California District Attorneys Association, California State Sheriffs’ Association and the Los Angeles Police Protective League.

Another California bill that could potentially pass this year — Senate Bill 439 — would limit the scope of the state’s juvenile justice system. The bill would exclude most youths 12 and younger from exposure to juvenile court, putting California in company with Massachusetts as having the highest minimum age in the country. Most states do not have a minimum age threshold; 20 currently do ranging from age 6 to 12.

Sara Tiano contributed to this story.