The article discusses the increasing use by international courts and tribunals of domestic explanatory materials—such as various statements, reports, and explanatory memoranda that usually complement the domestic approval of treaties—in the process of treaty interpretation. After examining the types of materials that can be used as interpretative aids in accordance with the general rules on treaty interpretation (Articles 31–32 VCLT), the article scrutinizes the various ways in which domestic explanatory materials have informed the interpretation of treaty provisions in the practice of international adjudicatory bodies. The analysis focuses on the legal grounds on which such materials have been admitted in the interpretative process, the reasons for which resort has been made to them by the adjudicating body, as well as the circumstances in which such documents have been invoked by the litigating parties. The article then discusses certain advantages and disadvantages stemming from the use of domestic explanatory materials in the interpretative process.
