Introduction

In the context of WTO jurisprudence, the term ‘municipal law’ is used interchangeably with the terms ‘national law’ and ‘domestic law’, in the same way that one finds these terms being used interchangeably elsewhere. WTO adjudicators have been confronted with a range of different issues relating to municipal law, one reason being that many of the measures challenged in WTO dispute settlement proceedings are municipal laws. The WTO agreements contain some specific provisions that speak to the relationship between those agreements and municipal law. For instance, Article XVI:4 of the WTO Agreement establishes that ‘[e]ach Member shall ensure the conformity of its laws, regulations and administrative procedures with its obligations as provided in the annexed Agreements’, and a small number of provisions in the covered agreements establish a ‘renvoi’ to each Member's national law to define certain terms. Otherwise, when confronted with questions relating to municipal law, WTO adjudicators have often fallen back on general international law concepts and principles of wider applicability. This chapter reviews WTO statements of wider applicability relating to: (i) the relevance of municipal law concepts and classifications to treaty interpretation; (ii) the invocation of municipal law as a justification for a failure to perform a treaty obligation; (iii) alleged violations of municipal law; (iv) the interpretation of municipal law by international tribunals; (v) the implementation of international obligations in municipal law; and (vi) representations made by a State regarding the operation of its municipal law.

Relevance of municipal law concepts and classifications to treaty interpretation

There are many examples of WTO adjudicators stating that a Member's municipal law concepts and classifications may be of limited relevance in the context of treaty interpretation. One of the stated reasons for this reluctance to rely on a Member's municipal law concepts and classifications is the concern that it would be inappropriate to characterize, for purposes of applying multilateral treaty provisions, the same thing differently depending on its legal categorization within the jurisdictions of different States.