The model of legal systems with ultimate power within their jurisdiction is challenged by the emergence of a plurality of legal systems, which all claim authority on their own and apply to the same legal cases, for example, national constitutional systems, the European Union, and the system of the European Convention on Human Rights. This development threatens the idea that law could resolve conflicts in a normatively justified way and not by mere political power. The issue, hence, is how the emergence of legal pluralism can be accommodated in a normative theory of law, normative in the sense that law constitutes a justified system of norms.