- Vienna Convention on the Law of Treaties — European Court of Human Rights (ECtHR) — International Court of Justice (ICJ)
The durability of a treaty requires its capacity to adapt and change in accordance with the evolution of the situation for which it was designed to apply. One of the means that allow such adaptability is evolutionary interpretation. This chapter underlines the twofold nature of this interpretative technique. According to a first approach, evolutionary interpretation may be considered as a way to identify the common will of the parties as it would have resulted if they had renegotiated the agreement taking into account the circumstances that have since evolved. In the silence of Article 31 of the Vienna Convention, the case law of the ICJ supports the view that such a dynamic interpretation is allowed only where it is possible to infer from the terms of the treaty that the text is open to considerations of factual or legal evolution after its conclusion. However, when a treaty establishes an organization designed to achieve a shared purpose, the international judge entrusted with task of interpreting that treaty is often prone to act as the depositary of the common finality. In such a case, evolutionary interpretation tends to a teleological one. It therefore leads to question how far such interpretation could be taken and may generate allegations of ‘judicial activism’.