Introduction: What is multilevel governance?

Over the last decades, the concept of multilevel governance (MLG) has stimulated fascinating research on the changing nature of political authority. Scholars have discovered the complexity, variety and dynamics of governance in multilevel settings within and beyond nation states, probed the merits of different explanations of these changes and, eventually, studied the consequences for politics, policymaking and democratic legitimacy. Thanks to this research, we have a good understanding of the underlying theoretical foundations of MLG, its historical evolution, its varieties and political dimensions. Yet the advancement of scientific research has come at a price. On the one hand, highly sophisticated and empirically rich research has revealed various patterns of MLG and many intricate details regarding their evolution, operation and consequences (Bache and Flinders 2015; Enderlein, Wälti and Zürn 2010; Piattoni 2010). On the other hand, the concept has lost its analytical clarity and tends to become a catch-all category (Stephenson 2013: 817–818). There is obviously need for a conceptual framework that does not conceal but explicates different aspects covered by the term. Such a framework is essential to guide comparative research that reflects varieties of MLG and contributes to advance theoretical reasoning on the causes, operation and consequences for politics and policymaking.