A principled approach

The use of principles in WTO dispute settlement as proposed in this book would not mark a radical break with the tradition of WTO Tribunals. However, it would involve a clearer articulation of the legal basis and justification for using principles, and a more precise investigation of the nature and scope of principles used. In this book I have identified three types of principles that are capable of reasonably clear definition, have a recognised basis in international law, and are suitable for examination in the specific context of the WTO, namely: principles of WTO law; principles of customary international law; and general principles of law. In many cases, these types of principles can and should be used by WTO Tribunals to interpret WTO provisions. In a narrower set of circumstances, WTO Tribunals should be prepared to use certain principles in non-interpretative ways, for example to resolve procedural issues.

The need for principles in interpreting the WTO agreements is inevitable, given the inherent uncertainty of language and gaps in treaties. Moreover, an important objective of the WTO dispute settlement system is certainty: in particular, the ‘security and predictability to the multilateral trading system’. As Lord Mansfield stated in Vallejo v. Wheeler: