Change, Stability and Stability by Change in the Law of Treaties: Rebus Sic Stantibus

The principle of pacta sunt servanda, according to which every treaty in force is binding upon the parties to it and must be performed in good faith aims at maintaining stability in international legal order. However, in cases where important change of circumstances occurs with regard to those existing at the time of the conclusion of a treaty, the balance between the parties may be disturbed and the aim and the purpose of the treaty may become meaningless. Therefore, if the principle of pacta sunt servanda is interpreted as containing no exception, States would be reluctant to establish contractual relationships that could not be terminated even in very different conditions and circumstances. This would certainly cause instability in international relations. International law aims at establishing the balance between stability and change by the principle traditionally referred to as rebus sic stantibus which is based on the idea that treaties cannot be considered as being independent from the conditions that paved the way for their conclusion. According to this principle, in some cases where a fundamental change of circumstances which has occurred with regard to those existing at the time of the conclusion of a treaty, and which was not foreseen by the parties, these latter may terminate the treaty or withdraw from it. Although being a settled principle of positive international law, the meaning of rebus sic stantibus generates intensive debate among States and national and international judicial instances. Article 62 of the 1969 Vienna Convention on the Law of Treaties and the international jurisprudence interpret the principle objectively in light of the “shared expectations” of the parties to international treaties. Whereas States seem to invoke the principle based on their subjective “vital interests”. This article discusses how the principle needs to be interpreted to achieve its aim without being discretionary used by States.