Professor Markus Wagner was invited to act as commentator on the work of Professor Ernst-Ulrich Petersmann, Professor Emeritus at the European University Institute in Florence, Italy. During the panel at the law faculty of the Universidad Autonoma de Madrid in Madrid, Spain, Petersmann presented his work "Constituting, Limiting, Regulating and Justifying Multilevel Governance of Interdependent Public Goods: From Constitutional Nationalism to Multilevel Constitutionalism and Cosmopolitan Constitutionalism?" Petersmann's book attempts to lay out a blueprint for how to incorporate popular input into the decision-making process in international institutions. Professor Wagner's comments focused on Ernst-Ulrich Petersmann's core thesis, highlighting the need for institutionalized mechanisms while pointing out the existing possibilities within those mechanisms to better incorporate people's concerns. Professor Wagner teaches and writes in the fields of international law, international economic law and comparative law.