Twenty years of the WTO Appellate Body’s “fragmentation jurisprudence”

The World Trade Organisation’s new dispute settlement machinery was one of a number of new international courts and tribunals established during the long decade between the end of the Cold War and the beginning of the new millennium. For international lawyers – long accustomed to life on the margins – the proliferation of new and vibrant specialised regimes of international law was both energising and anxiety producing. At the heart of the anxiety, as Koskenniemi and Leino have described,1 was a concern about the incoherence of international law, famously leading at the end of the 1990s to a debate amongst international lawyers about the dangers of the growing normative incoherence of the system. What would happened when two international tribunals sought to apply inconsistent rules to the same dispute? Could one tribunal legitimately consider rules of law which fell outside its specialised mandate, so as to reduce the chance of conflict? Given its position as one of the most significant, and certainly the most active, of this new generation of international tribunals, the WTO’s Appellate Body has been closely scrutinised for the approach it has taken in cases which appear to raise questions about the relationship between WTO law and so-called ‘non-WTO law’, and a range of views have emerged within WTO scholarship about what the appropriate role that the WTO should play in this respect. This contribution reflects on the first 20 years of the Appellate Body’s jurisprudence, specifically as it relates to questions of normative fragmentation. The first section provides an overview of some of the highlights of the WTO’s jurisprudence in this regard, focussing in particular on the often-discussed issue of the use which has been made of general public international law in the context of WTO dispute settlement. The second section then suggests that the primary driver of the Appellate Body’s approach so far has not been the institutional myopia and normative closure of which they are sometimes accused, but rather a judicial sensibility which valorises the virtues of modesty, caution and self-restraint. In the third section, I offer a related argument, having to do with the causes of fragmentation. It is typically said that the problem of fragmentation arises from the specialised mandates of many international legal regimes, and the lack of institutionalised coordination between them. I note, however, that in fact the mandates, boundaries and specialisms of these regimes are not fixed in advance, but are in part the product of ongoing boundary work – and that the ‘fragmentation’ jurisprudence of the Appellate Body has predictably involved boundary work of a particularly intense kind