How did Ketanji Brown Jackson’s first Supreme Court dissent challenge a murder conviction?

Justice Ketanji Brown Jackson’s first Supreme Court dissent challenged the Court’s refusal to hear an appeal regarding a first-degree murder conviction. In this case, the prosecution had suppressed evidence that its key witness possessed an intellectual disability, which could have significantly impacted the witness's ability to perceive facts and testify accurately.1

Jackson argued that the Court of Appeals for the Sixth Circuit applied an incorrect legal standard when evaluating whether this suppressed evidence warranted a new trial. While the Sixth Circuit required the defendant to prove it was "more probable than not" that the outcome would have changed, Jackson contended that the proper standard was a "reasonable probability" of a different outcome.1

She emphasized that Supreme Court precedent establishes "reasonable probability" as a lower, distinct threshold. By conflating the two, the lower court failed to recognize the substantial likelihood that the jury’s verdict would have been different had they known of the witness's disability. Consequently, Jackson argued for a summary reversal to ensure the case was analyzed under the correct legal standard.1