In a recent decision involving treaty law, the Netherlands Supreme Court accepted "compartmentalization" and ruled that the new (1980) Netherlands-United Kingdom treaty has "partially maintaining force" instead of "excluding force". This article discusses the Supreme Court's decision and the doctrine of "transitional law" in the Netherlands and briefly describes Dutch case law on compartmentalization under national law. The article also considers the corresponding decisions at the treaty level and concludes that this decision is unique. The article examines whether a justification for the decision in this stand-alone case can be found in relevant international principles - in this case those in the Vienna Convention on the Law of Treaties. The article concludes that the answer to this question is no.