In affirming the court of appeals' denial of the habeas petition, the Supreme Court differentiated the constitutional treatment accorded the two aspects of a capital sentencing procedure. According to the Court, first, in the eligibility phase, the jury narrows the class of defendants eligible for the death penalty, often through the consideration of aggravating circumstances. At this point the Court stressed the need for channeling and limiting the jury's discretion. 522 U.S. at 275-76, 118 S. Ct. at 761-62, 139 L. Ed. 2d at 709-10. In contrast, during the selection phase, the jury determines whether to impose a death sentence on an eligible defendant. Here the Court emphasized the need for a broad inquiry into all relevant mitigating evidence in order to allow an individualized determination. Id. Under this view of the capital sentencing process, the Buchanan Court concluded that a mandatory instruction on mitigation was not constitutionally required. In Rhines, the United States Supreme Court addressed the constitutionality of a state statute requiring judges to instruct juries about the Governor's authority to commute a sentence. The Court held there to be no constitutional barrier to the state legislature's decision to impose such an instruction on juries. It opined that such an instruction did not preclude individualized sentencing determinations or consideration of mitigating factors, nor did it inject an impermissibly speculative element for the jury's determination. Notably, the majority opinion concluded with the remark that its decision was not intended to override the contrary judgment of states that capital sentencing juries should not be permitted to consider the gubernatorial power to commute a sentence. Id. at 1013, 103 S. Ct. at 3460, 77 L. Ed. 2d at 1188. In essence, finding no constitutional infirmity, the Court deferred to the decision of the California state legislature.