The European Union faces the challenge of expansion, deepening, and democratization. Coupled with the necessity to assert itself in an increasingly complex international environment, this triple challenge presents an opportunity for our continent to leverage the diverse political cultures and regional identities that have developed into a significant leap in integration policy. In modern Europe, where multi-ethnic, multi-cultural, and multi-religious states are the norm, the federal order is best suited to tackle this unification task—with the long-term goal of a European Federation. In their contributions, the authors analyze the possibilities and limitations of the specifically European, supranational manifestation of the federal design principle, against the backdrop of two centuries of American federal state experiences.