Time-Travelling Rules of Interpretation: Of ‘Time-Will’ and ‘Time-Bubbles’

Abstract

International courts and tribunals are fond of paying lips service to the fact that Articles 31-33 of the Vienna Convention on the Law of Treaties (VCLT) reflect customary international law. This allows them to draw inspiration from the text of the VCLT even in cases where a treaty that is being interpreted was concluded either before 1980 (the date of entry into force of the VCLT), or between parties that are not parties to the VCLT. This fiction may be useful for relatively recent treaties but the question is whether it can hold water in situations where the treaties being interpreted are from the early 20th, 19th century or even earlier. The present Chapter examines, whether the customary rules of interpretation can indeed be considered to have remained relatively unchanged through the ages, as was briefly suggested in Kasikili/Sedudu, or whether they are subject to change as any rule of international law and, thus, international courts and tribunals sometimes when interpreting old treaties apply the wrong rules of interpretation in clear contravention of the non-retroactivity principle.