Argument: It is impossible to determine that deterrence is not working
Frank Carrington (1978) - is there any way one can tell whether the death penalty deters murders from killing? There is no way one can tell whether the death penalty deters murderers from killing. The argument goes on that proponents of capital punishments should not have to bear the burden of proving deterrence by a reasonable doubt. Nor should the abolitionist have to prove deterrence by a reasonable doubt -neither side would be able to anyway.
Justice Stewart held in the Supreme Court in Gregg v. Georgia: - Although some of the studies suggest that the death penalty may not function as a significantly greater deterrent than lesser penalties, there is no convincing empirical evidence supporting or refuting this view.