THE MICHIGAN HALL of Justice, home to the Michigan Supreme Court, in Lansing, Mich. (AP Photo/Carlos Osorio, file)

DETROIT (AP) — The Michigan Supreme Court made an extraordinary change to the state’s sentencing law Thursday, striking down automatic, no-parole prison terms for 19-year-olds and 20-year-olds convicted of murder.

As a result, hundreds of people will be eligible to return to local courts to ask for a shorter sentence and an opportunity for freedom. At the same time, anguished friends and relatives of murder victims will have to revisit the cases, too.

The Supreme Court, in a 5-2 opinion, said mandatory life sentences for people who were 19 and 20 at the time of the crime violate a ban against “cruel or unusual punishment” in the Michigan Constitution. The court made a similar decision for 18-year-olds in 2022.

A mandatory life sentence “that does not allow for consideration of the mitigating factors of youth or the potential for rehabilitation is a grossly disproportionate punishment,” Justice Elizabeth Welch wrote.

Michigan was among only 16 U.S. states that impose mandatory life terms on anyone convicted of first-degree murder who was over 18, according to the MacArthur Justice Center.

A life sentence in Michigan still can be possible for someone 19 or 20, though it will be rare. The burden will be on prosecutors to show that someone convicted of murder should never get a chance at parole. Judges will hear evidence about family life, mental health, education and other factors, the same process followed for people 18 or under.

Welch said the court’s decision was rooted in scientific research about brain development and a young person’s ability to fully grasp the consequences of their actions.

“As late adolescents mature into fully developed adults, they become less prone to reckless decision-making, more likely to consider and appreciate consequences, and less susceptible to peer pressure,” Welch said.

In a dissent, Chief Justice Elizabeth Clement said lawmakers, not the court, should decide whether to change the law.

“Courts should not reshape the law with every shift in scientific consensus, especially when it is the Michigan Constitution that is the subject of reshaping,” said Clement, who was joined by Justice Brian Zahra.

During arguments in January, Flint-area assistant prosecutor Katie Jory urged the court to think about the impact on victims’ families if nearly 600 sentences are reopened.

They will be “forced to reopen these old wounds, stop where they are in their grieving process, go in front of a court again and bare publicly their soul regarding the hurt that they have experienced based on the murder of their loved one,” Jory said.

The Supreme Court heard appeals on behalf of Montario Taylor, who was 20 when he repeatedly shot a man in the victim’s home in 2016, and Andrew Czarnecki, who was 19 when he was involved in the fatal beating of a man with a Christmas tree stand in 2013.

Since 2021, courts or lawmakers in Washington state, Illinois and Massachusetts have prohibited life sentences for people under 21 or made parole opportunities available.