Succession to EU Membership - The Legal Challenges of Internal Enlargement

Nationalism seems to have gained momentum in some parts of our continent (Scotland, Catalonia, Flanders,…). Considering the current context, the emergence of breakaway regions as fully-fledged states is no longer a chimera but has become intellectually conceivable. The relationship between these potentially independent states and the European Union is one of the pivotal issues that this scenario raises. Automatic accession or ex novo admission? Would those new entities naturally succeed to EU membership? Two conflicting theses have emerged, and the debate rages between the Union, its member states and nationalist political parties. This article intends to clarify the situation. After summarizing the position of the various actors involved, it will then thoroughly scrutinize European and international law, reaching a legally-sound conclusion on the issue. Finally, given its findings, this article will identify lines that should guide the Union’s reaction, should this scenario become a reality.