The Vienna Convention on the Law of Treaties (VCLT) suggests that a look into the past of a treaty may be necessary when interpreting it. Articles 31 and 32 of the WCL refer to later customs and later agreements but also to preparatory work, respectively, known as travaux préparatoires (Article 32). The provisions thus refer to different points in time, either to what happened after the entry into force of the treaty or to what formally existed and was negotiated before the entry into force of the treaty.
The focus of the presentation was on questions dealing with the process of treaty interpretation in the past and today. Preparatory works are increasingly not being produced and it appears that they are losing relevance.
Both Art 31 and Art 32 WCC thus provide an "organised" set of rules for treaty interpretation. However, from a practical point of view, the real question is whether these references to a treaty's past can still be helpful in the interpretation process today.
The Institute of International Law and International Relations thanks Prof. Liesbeth Lijnzaad for her visit to Graz and for the interesting lecture. We would also like to thank all participants, both in person and online, for their exciting contributions to the discussion.
More information on the GILDS event series can be found here.