The secession on a European Union Member State

The European Union has reached such a high degree of integration that a secession on any of its members states would cause very negatives consequences. In this case, should the European Institutions consider this problem as merely an internal problem of the member state, accordingly the international law? Or should take part and intervene, with appropriate mechanisms, in order to protect the European Union and its objectives? This is the dilemma that the author of this article faces.