Erika de Wet

• Underpinning a legal system with certain values and helping to resolve norm conflicts is in domestic legal systems usually achieved through hierarchical superiority of certain norms of a constitutional nature. The present paper examines the question whether jus cogens can discharge this function within the traditionally horizontal and decentralized international legal order. In so doing, it commences with an overview of the historical origins of peremptory norms in legal scholarship, followed by its endorsement by positive law and courts and tribunals. This analysis illustrates that there are lingering uncertainties pertaining to the process of identification of peremptory norms. Even so, the concept has been invoked in State executive practice (although infrequently) and has been endorsed by various courts. However, such invocation thus far has had a limited impact from a legal perspective. It was mainly confined to a strengthened moral appeal and did in particular not facilitate the resolution of norm conflicts. The contributionUnderpinning a legal system with certain values and helping to resolve norm conflicts is in domestic legal systems usually achieved through hierarchical superiority of certain norms of a constitutional nature. The present paper examines the question whether jus cogens can discharge this function within the traditionally horizontal and decentralized international legal order. In so doing, it commences with an overview of the historical origins of peremptory norms in legal scholarship, followed by its endorsement by positive law and courts and tribunals. This analysis illustrates that there are lingering uncertainties pertaining to the process of identification of peremptory norms. Even so, the concept has been invoked in State executive practice (although infrequently) and has been endorsed by various courts. However, such invocation thus far has had a limited impact from a legal perspective. It was mainly confined to a strengthened moral appeal and did in particular not facilitate the resolution of norm conflicts. The contribution further suggests that this limited impact results from the fact that the content of peremptory obligations is either very narrow or very vague. This, in turn, implies a lack of consensus amongst States regarding the content (scope) of jus cogens, including the values underlying these norms. As a result, it is questionable whether the construct of jus cogens is able to provide meaningful legal protection against the erosion of legal norms. It is too rudimentary in character to entrench and stabilize core human rights values as the moral foundation of the international legal order.…