International Investment Protection and Constitutional Law: Between Conflict and Complementarity

The chapter introduces into how the interaction between international investment law and constitutional law has evolved and provides an overview over the contributions to the present volume. Looking at international investment arbitration and constitutional adjudication, the chapter argues that the relationship between investment law and constitutional law has moved from occasional encounters to structured interaction. So far, however, this interaction has been analyzed mostly in terms of normative tensions and conflicts, with both constitutional courts and investment arbitration forwarding their own claim for authority and supremacy. In engaging with the contributions to the present volume, the chapter explains the sources for, and operationalization of, these competing claims for supremacy and explores ways of overcoming and facilitating co-existence and complementarity between international investment law and constitutional law.