This article describes the basic components of the operating and normative systems as a conceptual framework for analyzing and understanding international law. There are many theoretical questions that follow from the framework that embodies a normative and operating system. We briefly outline one of those in this article, namely how the operating system changes. In doing so, we seek to address the puzzle of why operating system changes do not always respond to alterations in the normative sphere. A general theoretical argument focuses on four conditions. We argue that the operating system only responds to normative changes when response is “necessary” (stemming from incompatibility, ineffectiveness, or insufficiency) for giving the norm effect, and when the change is roughly coterminous with a dramatic change in the political environment (that is, “political shock”). We also argue, however, that opposition from leading states and domestic political factors might serve to block or limit such operating system change. These arguments are illustrated by reference to three areas of the operating system as they concern the norm against genocide.