The concept of the rule of law is invoked in a manifold set of circumstances which can be distinguished according to a horizontal and vertical dimension. On one hand, the rule of law assumes a central relevance in the context of disputes which involve disturbances of the equilibrium between the powers of different legal institutions. In this sense, it constitutes a violation of the principles enshrined by the concept of rule of law the passing of a piece of legislation which undermines the independence of the judiciary, excludes some administrative powers from the scrutiny of the latter.
On the other hand, in a vertical dimension, the rule of law is often referred to with respect to the legal constraints which inform the relations between legal subjects and the State. In this sense, the act of public officers which affects individuals fall outside of limits set by the rule of law any time that they illegitimately exceed the powers which are established in a foreseeable and contestable manner by positive law; or whereas an individual or a specific group is targeted by measures which violate the principle of legal equality before the law; or when those who are affected by legal power are not given the opportunity to challenge it through an effective legal remedy before a court of law. In this respect, the European Court of Human Rights has underlined that “one can scarcely conceive of the rule of law without there being a possibility of having access to the courts”.1