The principle of pacta sunt servanda has a long history in international treaty law. Its unwavering position as the fundamental principle governing contracts is undeniable. However, in the ever-changing world of international relations change should be regarded as an important part of treaty relations. This thesis will examine the relationship between treaty stability and change. It will examine the dichotomy these two notions have in international treaty law.
The Vienna Convention on the Law of Treaties is the most important instrument governing treaties. This thesis will concentrate on two specific Articles of set Convention, Articles 61 and 62. These Articles contain rules on ‘supervening impossibility of performance’ and ‘fundamental change of circumstances’ which is also known by its Latin phrasing of rebus sic stantibus. These Articles will be discussed thoroughly in order to gain a deeper understanding on what they are and how they work. This thesis will introduce the notion of these two Articles as being an integral part of international treaty law, and the necessity for them to be accepted as legitimate grounds for terminating a treaty. The dichotomy of stability and change will be reflected upon the discussion of pacta sunt servanda and Articles 61 and 62 of the Vienna Convention on the Law of Treaties.
The principle of rebus sic stantibus continues to have a troublesome character in international treaty law. It is considered to be the ‘terrible child’ of international law. Its essence and application are debated in judicial writings and international tribunals. This thesis will demonstrate the necessity of this principle in international treaty law. Because Articles 61 and 62 overlap and are so called ‘siblings’, it is important to examine them together.
Small island States in the Pacific will serve as a concrete example of the need to accept these Articles as grounds for terminating a treaty. These microstates may find themselves in difficult situations because of climate change and the subsequent rise of sea levels. Because they are submerging into the ocean, they may confront situations that cause their treaty obligations to become unfair or impossible to oblige to. These situations could call for the application of Articles 61 and 62 of the Vienna Convention on the Law of Treaties. There needs to be a way to understand these Articles as completing the principle of pacta sunt servanda and evolving the law of treaties in a way that accommodates to change.
