International norms on execution of the insane and the mentally retarded

Victor Hugo considered the death penalty to be the hallmark of barbarity. 104 International human rights law clearly contemplates abolition of the death penalty. To some extent, it has succeeded in promoting universal and imperative norms, as in the case of the prohibitions on torture and slavery. 105 With respect to the death penalty, results have been more gradual and the effort has met with more opposition. Although international norms now exist prohibiting the death penalty, 106 they are not yet widely ratified. This is why international organizations dedicated to the promotion of human rights have insisted upon strict limitation of the death penalty, including its total exclusion for certain categories, such as juveniles, pregnant women, the elderly, and the insane.
No treaty provision exists to exclude the insane from the death penalty. The conclusion that this prohibition represents a customary norm is an important one, with consequences not only in international law but also in domestic law since many states consider customary international law to be a part of their domestic law. Wherever a court concludes that in the absence of any domestic statutory provision to the contrary, customary international human rights law prohibits execution of an insane prisoner, a small step will be taken away from the barbarism lamented by Hugo.