Towards unity? The concepts of necessity and proportionality in exception clauses across international law

Thesis

Exception clauses in treaties and their analogues in subfields of customary international law (such as the law on state responsibility) allow states to unilaterally 'derogate' from otherwise binding rules of international law, typically under the condition that the derogating action is necessary and proportionate. While necessity and proportionality thus undoubtedly play a central role in exception clauses, they have been curiously understudied and remain startlingly unclear; international courts have struggled to interpret necessity/proportionality. In addition, despite the wide-spread inclusion of necessity/proportionality in exception clauses across international law, comparative studies across contexts are exceedingly rare.

This thesis studies the concepts of necessity and proportionality enshrined in exception clauses across a variety of treaties and subfields of international law – specifically, the law on state responsibility, the law on self-defence, and the general exception clauses in WTO law -, and in particular how they are applied and reviewed by international courts. The thesis explores the concepts of necessity and proportionality in general, clarifies how they are applied in the context of the surveyed rules, and reveals the degree to which necessity/proportionality overlap across the different contexts, demonstrating the existence of a unified core. It argues further that this unified core can be utilised to facilitate cross-interpretation between different contexts, which offers an original strategy to overcome some hitherto unresolved difficulties with respect to the interpretation of necessity/proportionality in exception clauses.

The thesis is divided into two parts. Part I (chapters I-III) analyses and compares the concepts of necessity/proportionality as well as how compliance therewith is reviewed by international courts across the surveyed rules. Part II (chapter IV) explores cross-interpretation of necessity/proportionality across contexts with reference to its unified core content.

Authors: Lieflaender, T

• DOI: 10.5287/ora-yrpzmxxkb
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford