Harry Blackmun

“ Twenty-four states permit imposition of the death penalty based on a finding that the murder was, in some ill-defined way, worse than other murders. The states use a variety of terms to denote this aggravating circumstance, with most statutes containing, either alone or in some combination, the terms 'especially heinous, atrocious, or cruel,' 'depravity of mind,' or 'outrageously vile wanton or inhuman.' These aggravating circumstances . . . have generated more controversy than any other aggravating circumstance. ”

“ Nor did the Gretzler court narrow the discretion of future sentencers simply by grouping its prior decisions into categories. The use of categories could serve to guide the sentencer if (a) the categories themselves are narrow enough that a significant number of homicides will not fall within any of them, and (b) the court indicates that a murder is covered by the aggravating circumstance only if it falls within one of the enumerated categories. ”

“ A cogent argument could also be made that the killing of a 21- or 55-year-old victim is especially blameworthy. But while none of these choices would be unreasonable, the State, with a statute of this kind, must choose. If the state court invoked first one argument and then the other, and ultimately found in virtually every case that the age of the victim made the murder "especially heinous . ”

“ The statutory aggravating circumstances do perform the state-law function of determining who will be sentenced to death. But the aggravating factors also perform the distinct function of determining which murderers are eligible for the death penalty as a matter of federal law. ”