Justice Ketanji Brown Jackson on Monday issued her first opinion since joining the Supreme Court, writing a dissent over the court’s refusal to hear an appeal from a death row inmate.

Jackson, the nation’s first Black female justice and the court’s only former public defender, expressed her view in a brief, two-page dissent that was joined by fellow liberal Justice Sonia Sotomayor.

Arguing that inmate Davel Chinn’s case should have been returned to a lower appeals court for further proceedings, Jackson said a lower court applied the wrong legal standard when weighing the extent to which evidence that Chinn claims was improperly withheld might have helped him at trial.

“Because Chinn’s life is on the line, and given the substantial likelihood that the suppressed records would have changed the outcome at trial based on the Ohio courts’ own representations … I would summarily reverse to ensure that the Sixth Circuit conducts its materiality analysis under the proper standard,” Jackson wrote.

The court’s refusal to take up Chinn’s appeal means fewer than four justices voted to hear it. In keeping with common practice, the justices’ vote count was not made public.

Chinn was convicted and sentenced to death for an aggravated murder he committed in 1989. He maintains that prosecutors failed to inform him that their key witness had a serious intellectual disability, which he claims would have undermined the jury’s confidence in the witness’s credibility.

“Justices Jackson and Sotomayor recognized the injustice in upholding Davel Chinn’s conviction and death sentence when the State suppressed exculpatory evidence that, based on the Ohio Courts’ own representations, was likely to result in an acquittal,” said Rachel Troutman, an attorney for Chinn. “Ohio must not exacerbate the mistakes of the past by pursuing Mr. Chinn’s execution.”  

Officials with the Ohio attorney general’s office did not immediately respond to a request for comment.

Jackson was sworn in as the Supreme Court’s newest member in June.

Updated at 11:55 a.m.