Poul F. Kjaer, Copenhagen Business School, has published Claim-Making and Parallel Universes: Legal Pluralism from Church and Empire to Statehood and the European Union. Here is the abstract.
When Neil MacCormick, in the wake of the launch of the Maastricht Treaty on European Union, went “beyond the Sovereign State” in 1993, he fundamentally challenged the heretofore dominant paradigm of legal ordering in the European context which considered law to be singular, unified and confined within sovereign nation states. The original insight of MacCormick might, however, be pushed even further, as a historical re-construction reveals that legal pluralism is not only a trademark of recent historical times, marked by the European integration process, but has also been at the very core of legal evolution in Europe throughout its modern history. The introduction of modern law in Europe can be traced back to the eleventh and twelfth century Investiture Conflict between the Church and the Emperor, a conflict which solidified the existence of two parallel universes of law, one Church-based and one empire-based, both of which rested, in principle, upon mutually exclusive claims to superiority, but which nonetheless became institutionally stabilized in a manner which allowed for mutual co-existence between them. The existence of such parallel universes of law has throughout, also in the “Westphalian world”, been a central characteristic of European law. It is suggested that the current constellation between the EU and its Member States should be viewed in this light.Download the article from SSRN at the link.