Introduction

In this chapter, I consider the legal basis for WTO Tribunals to use the three types of principles identified in the previous chapter in WTO disputes, taking into account the limited jurisdiction of WTO Tribunals and the DSU provisions restricting their powers and functions. Broadly, WTO Tribunals could use these principles in one of two ways: either in an interpretative manner, to understand the meaning of a particular WTO rule; or in a non-interpretative manner, as an independent substantive rule or a rule of procedure or evidence. These two ways of using principles overlap to some extent, and WTO Tribunals do not always make clear whether or how they are using such principles. This lack of clarity makes it difficult to assess the legality of WTO Tribunals' use of principles. It is also exacerbated by the fact that a principle may sometimes be used in either an interpretative or a non-interpretative manner to achieve the same result. For example, in Turkey – Textiles, the Panel had to decide whether certain challenged measures were attributable to Turkey or the European Communities–Turkey customs union. The Panel resolved this question by applying customary international law rules regarding state responsibility. However, Bartels argues that the Panel could have used these rules in interpreting the word ‘Member’ in GATT 1994 to achieve the same result.