I am a professor of international law at the Graduate Institute of International and Development Studies in Geneva, working on issues of international law, global governance and law beyond the state. At the same time, I am a fellow at the Hertie School of Governance, Berlin. Previously, I was ICREA research professor at the IBEI in Barcelona, a professor of international law at the Hertie School, a senior lecturer at the Law Department of the London School of Economics and Political Science, and a research fellow at Merton College (Oxford), New York University School of Law and the Max Planck Institute for Comparative Public Law and International Law in Heidelberg. I have also been a visiting professor of law at Harvard Law School. I hold a Ph.D. in law from the University of Heidelberg and a Diploma of European Law of the Academy of European Law in Florence, Italy. I am the author of Selbstverteidigung und kollektive Sicherheit (Self-defense and Collective Security, 2001) and of articles on the United Nations, hegemony in international law, and the legal order of global governance. My book, Beyond Constitutionalism: The Pluralist Structure of Postnational Law (2010), was awarded the 2012 Certificate of Merit of the American Society of International Law. In 2017, I received an advanced grant by the European Research Council for a project on “The Paths of International Law: Stability and Change in the International Legal Order”. In 2019, was awarded the inaugural Max Planck-Cambridge Prize in International Law. I am also a member of the Scientific Advisory Council of the European Journal of International Law, on the editorial board of the Journal of International Dispute Settlement and on the Council of the International Society for Public Law.