I wonder if the juries in death penalty cases are not automatically skewed? Surely jury selection will tend to eliminate those who oppose the death penalty, since there is an excellent chance they would nullify the verdict. The remaining death-penalty-approving jurors would then tend toward the hang-em-high, let god sort them out, looks guilty to me outlook...
Conversely a juror strongly opposed to the death penalty could get through selection and then refuse to convict a guilty perp.
Either way it does not seem good for justice.