This book engages in the vivid debate about the role of national parliaments in the future European democracy. These parliaments are widely regarded to be essential in reducing the EU’s democratic deficit, but it remains unclear how their function should be organised. Attempts to arrive at Union-wide regulation, for example in the constitutional treaty, have not resulted in a comprehensive regime based on a clear political philosophy. The purpose of this volume is to contribute to such a regime on the basis of a comparative analysis of scrutiny systems, as they exist today. In this respect, the book proposes a ‘bottom-up’ approach to European constitutionalism, which means that the political systems of the Member States are considered to be the prime source of inspiration, the main input, to the process of establishing supranational norms.