Based on a transatlantic dialogue between scholars, this work addresses the complex and changing relationship between levels of governance within the United States and the European Union. It examines modes of governance on both sides, analyzing the ramifications of the legitimacy crisis in our multi-layered democracies and moving beyond the current policy debates over devolution and subsidiarity. Its authors believe that in spite of the fundamental differences between them, both the EU and the US are in the process of re-defining a federal vision for the twenty-first century.