A certain degree of judicial discretion with respect to procedural matters is fundamental to all dispute settlement. However, due process must be respected and protected at all times to maintain the legitimacy of the system. In the international context, while national norms may be considered, there is generally very limited guidance on what steps a tribunal should take to ensure that flexible procedure effectively protects due process and in fact, what process is actually due. The development of policy guidance around procedural mechanisms to protect due process for the international community to consider when reforming existing and establishing new international dispute settlement systems will provide needed support and practical options for the requirements of due process in the broader international context. This work seeks to derive such policy options based upon a comparative analysis of three specifically selected international dispute settlement mechanisms, the World Trade Organization, the International Centre for the Settlement of Investment Disputes and the UNCITRAL Rules. These three mechanisms were selected based upon their international legitimacy but also based upon the differing subject matter they address to demonstrate that due process protection is fundamental, rises above specific subject matter and cuts across all types of international dispute settlement.

This work focuses on issues surrounding the balancing of procedural judicial discretion and flexibility with the need to protect due process. This is done initially through an analysis of the history of judicial discretion, procedural flexibility and due process – where do they come from, how were they developed and why are they so important? With respect to each system’s approach to the protection of due process, the analysis seeks to identify strengths and also weaknesses within each system and then compares and contrasts the identified weaknesses across all three of the systems reviewed. This exercise is intended to identify areas for improvement within each of the three systems but also to consider whether specific weaknesses identified are unique to a particular system or alternatively are commonly found in the world of international dispute settlement. From this analysis and the weaknesses identified, policy options to protect due process are developed and then applied back to the three dispute settlement systems to determine whether weaknesses previously identified are addressed. The goal is to provide the international community with practical and effective guidance and options to consider. Based upon the analysis of how the three considered dispute settlement mechanisms address the protection of due process, the development of common rules relating to discovery in an effort to ensure that all evidence is made available to the decision maker is identified as the primary existing gap to be addressed. Additional policy options developed highlight the benefits of a clearly defined substantive appeals mechanism and also the practice of looking to past precedent in order to ground future decisions