In the case of Jill L. Brown, Warden v. William Charles Payton in 2004, the U.S. Supreme Court ruled on a habeas corpus petition from a death row inmate in California who had been convicted of murder and rape. The Ninth Circuit court had previously granted relief to Payton based on his claim that during the penalty phase of his trial, there was an unconstitutional restriction on mitigating evidence regarding his post-crime religious conversion. However, this decision was reversed by the Supreme Court which held that no such constitutional violation occurred because "the sentencer" (i.e., judge or jury) is not precluded from considering any relevant mitigating evidence about a defendant's character or record when deciding whether to impose death sentence under California law.

In the dissenting opinion for the case of Jill L. Brown, Warden v. William Charles Payton, Justice Scalia disagreed with the majority's decision to uphold a lower court ruling that had overturned Payton's death sentence due to improper jury instructions regarding mitigating evidence. He argued that there was no reasonable likelihood that jurors would have interpreted these instructions in a way detrimental to Payton and thus they did not violate his constitutional rights as claimed by the defense. Furthermore, he contended that even if there were errors in instruction, they were harmless beyond a reasonable doubt given substantial aggravating factors present in this case including rape and murder convictions. Therefore, according to Scalia’s perspective, it was inappropriate for federal courts to intervene on state decisions unless clear violations of constitutional rights could be demonstrated.