A comparison of the Pennsylvania and Georgia death penalty statutes notes that Georgia gives the sentencer unlimited discretion to return a life sentence whereas Pennsylvania's law circumscribes sentencer discretion both in terms of the kind of evidence that may be heard and the manner in which it is to be evaluated. Several State courts have upheld the constitutionality of mandatory death penalty statutes, suggesting that they do not consider the difference between mandatory and permissive statutes as a significant issue. However, an analysis of Furman v. Georgia and Gregg v. Georgia demonstrates the conflict between nonarbitrariness and reliability and suggests that Chief Justice Burger's use of the concept of relevant mitigating evidence in Lockett v. Ohio attempted to reconcile these principles. This effort was not successful, as the entire structure of that opinion demonstrates that its starting point and major ground is reliability -- the assurance that death is the appropriate punishment. Because the concept of relevant mitigating circumstances is so flawed, Pennsylvania's mandatory scheme fails to satisfy the Supreme Court's insistence on a reliable death penalty sentencing system. Specifically, the statute does not permit the sentencer to consider attacks on the death penalty itself; it defines relevant mitigating evidence without regard for the community's desire for retribution, and requires reasons for sentencing decisions. The paper includes 276 footnotes.