Introduction

This chapter provides an introduction to the analysis of the substantive standards of treatment from a rule-of-law perspective. It shows that the rule of law has become a widely shared normative yardstick for assessing international investment law as a whole, including both investor-State dispute settlement and the substantive standards of treatment. The chapter provides an overview of the different conceptions of the rule of law (‘thin’ or ‘formal’ versus ‘thick’ or ‘substantive’) and introduces the contributions to the present volume against the background of two analytical angles. First, to assess to what extent the rule of law is reflected in the substantive standards of treatment contained in international investment treaties and how the rule of law can guide the standards’ interpretation. Second, to query what rule-of-law lacunae substantive standards of treatment leave, whether in respect of inconsistent interpretations, lack of coherence with competing rights and interests, disregard of domestic investors, or shortcomings in respect of investor obligations.