again there is both the moral issue of death penalty v the legal issue (especially as it pertains to the US)
one might for the death penalty morally in certain circumstances - it might be (mass) murder/rape/ etc etc - each person's line might be different or one might be in the camp that no matter what an eye for an eye just leaves the world blind...
then there is the legal issue of the death penalty and how it is applied
personally from my understanding the death penalty as a legal issue especially in the US is discrimination in practice not in theory but morally speaking I have nothing against the death penalty (in certain circumstances)