In what circumstances will a penalty be set aside if defense counsel fails to provide mitigating evidence in the penalty phase?

In People v. Deere, supra, 41 Cal.3d 353, 222 Cal.Rptr. 13, 710 P.2d 925, we held that the failure of defense counsel to present any mitigating evidence in the penalty phase of a capital trial at the request of the defendant required that the penalty be set aside. We discussed the state's interest in the reliability of the penalty determination and observed that "[t]o allow a capital defendant to prevent the introduction of mitigating evidence on his behalf withholds from the trier of fact potentially crucial information bearing on the penalty decision no less than if the defendant was himself prevented from introducing such evidence by statute or judicial ruling." ( Id. at p. 364, 222 Cal.Rptr. 13, 710 P.2d 925.) Defendant's penalty jury was equally deprived of information which would have assisted it in determining the appropriate penalty. ⁸ "[N]ot only did defendant not have a fair penalty trial--in effect he had no penalty trial at all." ( Id. at p. 368, 222 Cal.Rptr. 13, 710 P.2d 925.)