Agnes RydbergPhD StudentEmail: a.rydberg@qmul.ac.uk ProfileProfileThesis Title The Obligation not to Defeat the raison d’être of a Treaty Prior to its Entry into Force under the 1969 Vienna Convention on the Law of Treaties: A Law-making Treaty Perspective Supervisors Professor Malgosia Fitzmaurice Dr Paul Gragl Summary of research This thesis examines the nature, scope and content of Article 18 of the Vienna Convention on the Law of Treaties (VCLT), and how this provision fits within the realm of law-making treaties as compared to contractual treaties. Article 18 VCLT imposes an obligation on States not to defeat the object and purpose of a treaty prior its entry into force when: (a) it has signed the treaty or; (b) it has expressed its consent to be bound by the treaty, pending the entry into force of the treaty and provided that such entry into force is not unduly delayed. The provision expresses a rule of generality and abstraction, and has proven to be a rich source for complexities and uncertainties, both concerning the nature of the obligation and its precise scope and content. In addition, there is valid concern that Article 18 VCLT is less prone to create a well-defined interim obligation in relation to law-making treaties since the drafters were inspired by and based their work upon contractual thinking. There is accordingly a need to examine if a certain type of treaty, first and foremost law-making treaties, may call for an ‘adjusted’ application of Article 18 in order for the provision to preserve its effet utile. In order to answer these questions, the thesis brings together two forms of methodologies; a doctrinal method and an empirical method. The empirical element examines what understanding States have of Article 18 VCLT. The implications of the thesis might be that Article 18 VCLT, whilst being a legal obligation, inevitably is construed so as to render the interim obligation ineffective and fragile. In order for the provision to maintain a certain degree of utility, a different approach is needed when applied to law-making treaties.Research