Normally, treaties contain express provision on duration and termination. These can take a variety of forms, including indefinite duration with a right to terminate, or a conditional right to terminate. Various types of clauses are examined, together with the situation where a treaty contains no provision for termination or withdrawal. A treaty may also be terminated by consent or by conclusion of a later treaty. The chapter examines the relationship between treaty provisions and countermeasures, and analyses the right of one or more parties to terminate or suspend a treaty for material breach. It also examines other grounds for termination, including supervening impossibility of performance and fundamental change of circumstances (rebus sic stantibus), the procedure for termination, and special circumstances such as the severance of diplomatic relations or outbreak of hostilities.

Treaties rely on the assumption that certain circumstances, essential to the conclusion of the treaty, will remain unchanged. It is on the basis of those circumstances that parties reach an agreement and pacta sunt servanda aims to safeguard those shared expectations. Still, States can be freed from their contractual obligations through peaceful means, when circumstances leading to the conclusion of a treaty change and obligations under a treaty become unduly burdensome. An unforeseen fundamental change of circumstances can be invoked as grounds for terminating a treaty if it affects the essential basis of the treaty and radically transforms obligations still to be performed. These conditions can all be met when coastlines or ecological circumstances undergo fundamental changes, affecting the essential basis of maritime delimitation agreements or related agreements concerning resource management. However, treaties establishing boundaries are immune from termination or revision on these grounds. Still, such agreements can be reinterpreted as a result of fundamental, environmental changes and this exception arguably, only excludes maritime boundaries of the territorial kind.

Jessup’s Transnational Law challenges the state as the sole maker of international law. Nevertheless, the doctrine of transnational law advocated for the disrobing of the newly gained sovereignty in Asia and Africa. American corporate lawyers used transnational law to expand their international commercial arbitration practice. Next, in disputes arising from the expropriations by new states of property acquired from concession contracts investors found transnational law profitable. Effectively, Transnational Law, restoring a colonial status quo, facilitated the post-war internationalization of contracts to develop the law of economic protection of aliens. It wantonly focused far too much on “contracts” forgetting conveniently its “concessional” nature. The doctrine of transnational law grew from the McNair-Lauterpacht School of thought that “exploited ungrudgingly and to the full” the “rules” of “private law for the purpose of the development of international law”. The Suez crisis inaugurated the American lawyer's putting of transnational law into practice.