Doctrinal Approaches to the Problem of the Influence of a Fundamental Change in Circumstances on the Operation of Treaties

The paper is devoted to the study of the views on the problem of the influence of a fundamental change in circumstances on the operation of treaties that existed in the science of international law before the adoption of the Vienna Convention on the Law of International Treaties of 1969. The author analyzes the following approaches, common in international legal science, to the problem of applying the rebus sic stantibus clause in interstate contractual practice: its unconditional support; her denial; recognition of the admissibility of using a clause in the presence of a number of conditions.Based on the study of special scientific literature, conclusions are drawn regarding the validity and acceptability of each of the approaches, which to a certain extent contributes to a proper understanding of the true meaning of the current conventional norm on the impact of a fundamental change in circumstances on international treaties. An analysis of the first approach, which assumes the right of any of the states party to the treaty to refuse to implement it in the event of such a change in circumstances that seriously affects the fundamental rights of this state, leads to the conclusion that in the absence of clear criteria for the use of a clause, it is almost impossible to reliably answer the question of whether after a change in circumstances, the implementation of the contract will threaten the fundamental rights of the state. The denial of the rebus sic stantibus clause was argued either by challenging its legal essence or by stating its inconsistency with the principle of pacta sunt servanda. The third approach, which is the most realistic, won approval at the UN Vienna Conference on the Law of Treaties and was normatively enshrined in the Vienna Convention of 1969, which ultimately made it possible to remove uncertainty regarding the impact of a fundamental change in circumstances on the operation of international treaties.