What is the test for a jury trial waiver in a death penalty case?

The crux of the waiver decision is whether to submit the life-or-death penalty decision to a judge for his or her sole determination or to 12 lay jurors of differing backgrounds who must unanimously agree on a death sentence before it may be imposed. The importance of jury unanimity in the normative determination of the appropriate penalty has a character distinct from the importance of jury unanimity in the factual adjudication of guilt. Other courts have recognized as much. In Commonwealth v. O'Donnell (1999) 559 Pa. 320, 740 A.2d 198, the trial court had made clear during its penalty phase waiver colloquy that the defendants were "entitled to a jury trial in the death penalty phase" and that they had the right to present evidence "in mitigation of the application of the death penalty." (Id . at p. 212.) The Pennsylvania high court nonetheless found the defendants' jury trial waiver constitutionally inadequate, principally because the trial court had not explained that a sentencing jury must be unanimous in its verdict: "Given the

[3 Cal.5th 213]