The rapidly growing number of investors' disputes with states and the approach of arbitral tribunals, perceived by some, whether rightly or not, as being too investor-friendly, underlie a contentious debate about the need to strike a more effective balance between investors' rights under international investment agreements (IIAs) and the right of states to pursue legitimate regulation in the public interest. In this regard the European Union, with the exclusive external competence in foreign direct investment vested in it under the Lisbon Treaty, is emerging as the leader and driving force...