Interplay between the WTO Treaty and Other International Legal Instruments and Tribunals: Evolution after 20 Years of WTO Jurisprudence

Positioning the WTO treaty in relation to other international legal instruments and tribunals is a complex, multi-faceted challenge on which reasoned opinions diverge. This contribution (i) describes how answering the question is, to some extent, an “interpretation choice”, (ii) summarizes the highlights of WTO jurisprudence to date, and (iv) identifies a number of trends and contradictions, and explains how the question itself, and the factors pushing in one or the other direction, have evolved over time. In its case law to date, the Appellate Body (AB) has solved some questions, and thereby made important interpretation choices. General international law, and its centralizing force, has played a key role. The impact of non-WTO treaties, including free trade agreements, and the de-centralizing pull they exert, remains less clear. The recent AB report on Peru – Agricultural Products provides useful clues and is surprisingly open to other international law. In other respects, it fails to convince and risks imposing an unrealistic straightjacket making it difficult for the WTO to adapt. Over time, the debate has shifted from non-trade to trade concerns and from other rules outside the WTO to instruments not part of WTO covered agreements but still concluded within the WTO. The pull toward other rules (broadly supported by the EU) shifted from a desire to legitimize the fledgling WTO dispute settlement system to an urge to find more recent expressions of membership voice. Regime independence and, later, an exaggerated focus on multilateralism have guided resistance against other rules (a trend generally supported by the US). Overall, the AB has preferred the avenue of treaty interpretation, and a pre-existing legal hook that can be found within the WTO treaty, to refer to other rules. Not always with legal support, the AB also tends to more easily accept other rules concluded inside rather than outside the WTO, and procedural deviations over substantive updating.