By way of conclusion, this chapter seeks to provide an overall assessment of what draws the Court and the Commission together, and of the impact that their “special relationship” has produced. In pulling the threads together, it explains that the interaction between the two organs has turned out differently to that which was originally envisaged, and that the great weight accorded by each of them to the work of the other has challenged the exclusive basis of State consent for international law’s validity. In a legal system that remains heavily dependent on unwritten rules of customary international law that require authoritative determination, the ultimate result has been that the Court and the Commission together assume a public order role not foreseen for either of them by their founders.

This chapter provides a detailed account of the impact that the Commission’s work has had in shaping the Court’s case-law. In addition to surveying and classifying all those instances in which the Court has to date been ready to refer expressly to the Commission’s output, the chapter demonstrates that reliance on the Commission’s work has often been more implicit. The question is then posed as to the basis for such recourse and the advantage afforded by it.

This chapter sets the scene for an appreciation of the contemporary relationship between the Court and the Commission by tracing its roots in the broader ideal of the pacific settlement of disputes and the rule of law in international affairs. Taking stock of developments dating back to the nineteenth century, it illustrates that the long-standing movements for an international court and for an international code were not unrelated, and that a certain vision did exist for the way in which their present institutional manifestations were to interact. That original vision, which has been lost in time, has thus far attracted less attention from commentators than its importance requires.

This introductory chapter explains the scope and purpose of the present study; the methodology pursued; and the structure of argument presented in subsequent chapters.

This chapter addresses in detail those rare occasions in which the Court and the Commission have adopted differing positions on the legal questions before them. In exploring both the potential for such disagreements and how they have been handled, the chapter shows that these instances attest to the strength of the inter-institutional relationship rather than undermine it. It also points out, however, that harmony comes at a cost.

This chapter addresses the relationship between the Court and the Commission beyond the printed page. By focusing attention on the movement of members from one institution to the other, and to the customary exchanges in Geneva between the members of both the UN organs, it reveals the extent and contribution of the more subtle ties that bind the Court and the Commission.

This chapter examines the unparalleled influence that the Court’s decisions have had on the Commission’s codification and progressive development of areas of the law under its consideration. It illustrates not only the great extent to which many of the Commission’s propositions have borrowed their authority from the pronouncements of the Court, but also the significant impact of the latter on the Commission’s choices concerning terminology and programme of work. The chapter further demonstrates the Commission’s conscious efforts to support the Court’s cause more broadly, including by encouraging the expansion of the Court’s jurisdiction and by promoting the doctrine of the sources of international law enshrined in its Statute.