Until Monday, Oregon was the only state that allowed nonunanimous jury convictions.
The U.S. Supreme Court ended that in a decision involving a murder conviction in Louisiana which, until 2019, had also allowed nonunanimous jury convictions.
The Oregon District Attorneys Association said it is reviewing the opinion for its immediate impact on pending and closed criminal cases.
State Attorney General Ellen Rosenblum had warned the U.S. Supreme Court that the criminal justice system would be "overwhelmed" if it ruled that nonunanimous jury verdicts are unconstitutional. She wrote in a brief to the court last August that the ruling could invalidate hundreds or even thousands of convictions.
In 1934, voters decided to amend the state constitution to allow split-jury verdicts — a decision fueled by white supremacy and anti-minority sentiment. One newspaper said immigrants from southern and eastern Europe had made the requirement for unanimous verdicts "unwieldy and unsatisfactory."
Rosenblum had supported a move to repeal the amendment, noting the jury rule's links to racism and anti-Semitism. But she said such a change should be for cases "going forward," not retroactively.
Rosenblum did not immediately respond for a request for comment Monday.
In 2019, several lawmakers sponsored a resolution calling for a ballot measure to repeal the constitutional amendment. The resolution unanimously passed the House but died in the Senate.
The District Attorneys Association had supported the ballot initiative, saying it "would have allowed Oregon voters to decide this issue, without the uncertainty of retroactivity."
"ODAA acknowledges that a change to unanimous verdicts could make criminal convictions more difficult. However, it is a hallmark of our justice system that it should be difficult to take someone's liberty," the association said.
The Supreme Court ruled in a 6-3 vote Monday that juries in state criminal trials must be unanimous to convict a defendant.
Justice Neil Gorsuch wrote that the practice is inconsistent with the Constitution's right to a jury trial and that it should be discarded as a vestige of Jim Crow laws in Louisiana and racial, ethnic and religious bigotry that led to its adoption in Oregon in the 1930s.
The decision "has finally ended an unjust rule with a shameful past in Oregon," said professor Aliza Kaplan, director of the Criminal Justice Reform Clinic at Lewis & Clark Law School in Portland, Oregon.
"Now Oregon will be able to join the rest of the country and require unanimous juries in all criminal cases ensuring a more fair trial for all those accused of crimes and ensuring that all jurors' voices are heard and part of the decision making process as they should be," Kaplan said.
The clinic is available to assist those with non-unanimous jury convictions who remain in custody along with those no longer incarcerated who wish to revisit their convictions, she said.
The justices overturned the conviction of Evangelisto Ramos. He is serving a life sentence in Louisiana for killing a woman after a jury voted 10-2 to convict him in 2016. In 2018, Louisiana voters changed the law for crimes committed beginning in 2019.
