Does arbitration permit a self-sufficient contract? To what extent can relevance be disregarded without affecting the validity and enforceability of an award? What power does the arbitral tribunal have?

The multi-faceted role of arbitrators is complex and protean. While there is consensus on the fact that the nature of the international arbitrator’s role entails according the arbitrator wide-ranging powers and that the arbitrator also undertakes a panoply of obligations, the scope of these powers and duties is not always well defined.Views about the nature and scope of these powers and duties might diverge depending on whether arbitrators are seen as service providers, justice purveyors, or both. Following a brief overview of this core question, the contribution proceeds to identify the sources of an arbitrator’s powers. Next, the most important duties of international arbitrators, including those pertaining to ethical obligations, the need to ensure due process, the necessity to apply the proper law, the duty to provide a reasoned award, and several others are explored. This contribution also highlights the most important rights of international arbitrators, such as the right to receive good faith cooperation from the parties, as well as the rights to remuneration and immunity, amongst others. Finally, we make some observations on ways in which the rights and duties entailed by the complex mandate of arbitrators can be reconciled in the event of conflict.

Lex arbitri (or ‘law of the arbitration’) is the law applicable to an international arbitration based upon the legal seat designated by the parties. The content of lex arbitri is dictated not by international law, but rather by the national law on international arbitration of the chosen jurisdiction. Typically, lex arbitri will address issues relating to the constitution of the arbitral tribunal and the conduct of the arbitration, including the extent to which local courts may be called upon to assist the arbitration process or may review and enforce any potential award, and the legal limits of arbitration in a jurisdiction.This chapter will consider the impact of lex arbitri on international commercial arbitration on the one hand and international investment treaty arbitration on the other.ICSID investment arbitrations are substantially ‘delocalized’ through the legal framework of the ICSID Convention, reducing their dependency on lex arbitri.By contrast, non-ICSID investment arbitrations are ‘localized’ in the seat of arbitration, and therefore are subject to lex arbitri.The direction of travel of international investment treaty proceedings, shown by complex bespoke procedural regimes in specific IIAs and negotiations for a Multilateral Investment Court, international investment disputes may ultimately ‘graduate’ out of dependence on lex arbitri.

Arbitration is a form of administration of justice that is distinguished from that administered by state courts fundamentally in that the basis of the arbitrators’ jurisdiction – at least in the case of voluntary arbitration – is the consent of the parties in dispute.