SEATTLE (AP) — The Washington state Supreme Court on Thursday overturned the automatic life-without-parole sentences given to two men for murders committed when they were 19 and 20, saying judges must consider the youthfulness of such defendants in sentencing them.

The ruling appeared to make Washington the first state to ban mandatory life-without-parole terms for offenders who, while over 18 and legally considered adults, might remain in adolescence from a brain-development standpoint.

Lawmakers in a few states — including Illinois, Nebraska and Connecticut — are this year considering bills that would ban life-without-parole sentences for young adults, said Josh Rovner, a senior advocacy associate at The Sentencing Project, a Washington, D.C.-based nonprofit. Some others, including Florida and California, have already adopted laws that allow youthful adult offenders to be treated with leniency, but they exempt murder defendants.

“It's the right direction for courts and legislatures to go,” Rovner said. “Nothing happens on one's 18th birthday. People into their mid-20s have a lot more in common with 15-year-olds than was previously understood.”

Kurtis Monschke and Dwayne Bartholomew were convicted in separate cases decades ago of aggravated first-degree murder, which under state law has historically been punishable only by the death penalty or life without possibility of release. The court has since struck down capital punishment as unconstitutional, leaving an automatic sentence of life without release as the only punishment for adults convicted of the state's most serious offense.

The U.S. Supreme Court has already held that juveniles — those under 18 — cannot be given automatic life sentences for murder. But in a 5-4 decision Thursday, the majority of the Washington Supreme Court said the same rationale must apply to 18- to 20-year-olds.

Under the ruling, courts in Washington can still sentence such young adult offenders to life without parole, but only after first considering whether their youth weighs in favor of a lesser punishment, the majority said.

“Just as courts must exercise discretion before sentencing a 17-year-old to die in prison, so must they exercise the same discretion when sentencing an 18-, 19-, or 20-year-old,” Justice Sheryl Gordon McCloud wrote in the lead opinion.

It was not immediately clear how many convicted murderers might be entitled to new sentencings under the ruling, but Bartholomew's lawyer, Tim Ford, said it was at most 26. That's how many 18- to 20-year-olds have been convicted of aggravated murder in Washington since 1981, he said; some may since have died or had convictions overturned.

Bartholomew was convicted in the killing of Paul Turner II, a Tacoma laundromat attendant, in 1981 after telling his brother he was going to rob the business and leave no witnesses. He was 20 at the time, suffering from depression and other mental health problems, and requested the death penalty when he was arraigned.

Ford, who has represented him for nearly 40 years, said Bartholomew's case has gone up to the U.S. Supreme Court four times and the Washington Supreme Court six times.

“He's lived a long time without much hope,” Ford said. “Hopefully he'll have something to look forward to other than dying in prison.”

Monschke was 19 in March 2003 when he and two other members of a white supremacist group fatally beat Randall Townsend, a 42-year-old homeless man, also in Tacoma, to earn red shoelaces, a symbol that the wearer had assaulted a member of a minority group.

The dissent objected to exempting such young adults from the same automatic punishment that older convicts must receive. The Legislature has decided that 18-year-olds can form contracts, drop out of school, get married, work a hazardous job and serve in the military — and it's not unreasonable for the Legislature to also find that they should face the full consequences of their crimes, Justice Susan Owens wrote.

“Children are different, certainly. But Monschke and Bartholomew were not children when they brutally murdered their victims,” Owens wrote.

She noted that no other state court or legislature had extended such protections to 18- to 20-year-old killers.

Although 18-, 19- and 20-year-olds can still be sentenced to die in prison under the ruling, the dissent questioned whether that could realistically occur: How are judges to determine whether a crime represents a defendant’s “transient immaturity,” warranting a lesser sentence, as opposed to “irreparable corruption,” warranting life without parole?

The ruling vacates the sentences Bartholomew and Monschke received and sends their cases back to Pierce County Superior Court for new sentencing hearings.