This article examines the interpretation of rules as an essential part of their
meaning. It starts with some of the most foundational rules – pacta
sunt servanda, for instance – and points to their contested
nature. It looks at some of the causes of this inherent contestability and its
effects on the international system. It concludes by noting that appeals to rules
never settle a debate, but only begin the interpretative process that constitutes
the international system. While this interpretative licence does not lead to
complete anarchy, it does leave open a wide range of outcomes in rule-governed systems.
