The separation of powers is seen as one of the hallmarks of a constitutional legal order. Each country rests on some form of division between the three branches of government. Traditionally, it is seen as a fundamentally national concept, with each state deciding for itself how to model the relationships between these branches, based on its own specific background. However, a recent evolution can be discerned, where the domestic separation of powers is directly influenced by international legal orders.
This paper addresses the impact that two international courts, the ECtHR and the ECJ, have on the domestic separation of powers and its checks and balances. It gives examples of what kind of separation-of-powers issues are brought before these courts and addresses what their impact is and how far-reaching it may be for the countries concerned. Finally, it asks the question if it is still tenable to perceive the separation of powers as an exclusively domestic doctrine.