Dan Koffler questions those who claim to be principally opposed to the death penalty "with exceptions":

...shouldn't it be obvious that opposition to the death penalty is only meaningful in precisely the sorts of purported-to-be-exceptional cases that offend societal moral intuitions the most deeply? Who is arguing for the death penalty in cases of mundane, everyday felonies? [There is somebody, I'm sure--ed.] I'm against capital punishment in all cases because I think that a realm of autonomy manifestly inclusive of one's own physical existence is intrinsic to the very notion of citizenship, and that no citizen, therefore, no matter how bestial a criminal, is property of the state such that he can be executed by state fiat. And since the government really is a social compact, I'm revolted by the fact that every application of the death penalty makes me a party to a premeditated killing. Now, I recognize that any practicable moral system includes an escape hatch for "emergency" scenarios, such that, e.g., killing in self-defense is morally justified. The death penalty, and the notion of "exceptions" to the rule against state-sanctioned killing, is plainly not such an emergency case. Prisoners in shackles do not create the immediate overriding imperative for lethal action that's necessary for an emergency to obtain. The upshot of that is that opposition to the death penalty not only can't admit of exceptions, but is a rare example of a moral legislation that is both absolute and practicable.