Mutual Supportiveness as a Principle of Interpretation and Law-Making: A Watershed for the ‘WTO-and-Competing-Regimes’ Debate?

This article focuses on the principle of mutual supportiveness as a key legal tool to address tensions between competing regimes, with specific reference to the articulation of the WTO system with other subject areas protecting essential interests of the international community, such as in particular the right to health, cultural diversity, and environmental protection. It argues that the multiple references to mutual supportiveness found in recent treaties and other legal instruments should not be briskly dismissed as mere political statements devoid of any normative significance. On the contrary, while such reiterated references are important in terms of progressive consolidation of a general principle of international law, mutual supportiveness seems to be characterized by two remarkable legal dimensions. The first is its interpretative dimension, which serves the purpose of disqualifying solutions to tensions between competing regimes involving the application of conflict rules. The second is the law-making dimension of mutual supportiveness which comes into play when efforts at reconciling competing rules have unsuccessfully been exhausted. This dimension implies a duty to pursue good faith negotiations aimed at the conclusion of law-making instruments, including treaty amendments, which clarify the relationship between the competing regimes at hand. This duty is especially important for the ongoing WTO Doha negotiations which call into question non-trade regimes and values, for instance the fair and equitable use of biological resources under the 1992 Biodiversity Convention. Most importantly, either for its nature as a general principle or for its recognition as a standard internal to the WTO, mutual supportiveness under the guise of a duty to negotiate in good faith would also bind WTO Members which are not parties to the competing treaty regime which needs accommodation in WTO law.