Similar to theoretical accounts of the rule of law, also in the case law, the rule of law is a layered concept with a core content. Also, in both contexts the quality requirements of legality and the existence of judicial safeguards form the core contents of the rule of law. In addition, procedural rights can be seen as part of the core of the rule of law. The core contents of the rule of law in the case law of the the European Court of Human Rights (ECtHR) is comparable to theoretical considerations on the rule of law as they are both formal and yet form a meaningfull restraint of arbitrary governmental power. However, a difference between legality in the case law compared to theory on legality is that the quality requirements set to national laws allow the ECtHR to achieve a balance between deference for national law and effective review. The rule of law is thus a tool of the ECtHR to balance subsidiarity and unity. Even though substantive human rights are not part of the core of the rule of law as a concept of the case law, the value of the rule of law ultimately lies in the protection of the Convention rights. It is the ability of the Convention system to protect individuals against arbitrary power which sets an authoritative example for the development of the rule of law in international law.