The term “governance” refers to interactive forms of political steering, characterized by the coordination of a wide spectrum of actors in pursuit of common goals (e.g., Rhodes, 1996; Pierre & Peters, 2000, 2005; Kooiman, 2003; Torfing, Peters, Pierre, & Sörensen, 2013; Ansell & Torfing 2016). Governance processes involve multiple actors and institutions into cooperative relationships and network structures. The corresponding steering mechanisms may range from hierarchical rule to mere persuasion. The governance perspective appeared particularly suited to analyze political steering in the European Union (EU). The Union is not sovereign; it therefore developed steering mechanisms that do not (or only partly) rely on formal competences and hierarchical rule. The evolving system of European governance constituted the EU as a multilevel polity, held together by interlocking relationships of policy coordination and cooperation (Marks et al., 1996; Hooghe & Marks, 2001; Piattoni, 2010). Scholarly reflection on EU governance evolved comparatively late during the 1990s (Hix, 1998); it proliferated after the turn of the century, when the European Union introduced the so-called Open Method of Coordination (OMC) (Kohler-Koch & Rittberger, 2006). Later, the perspective widened to the whole spectrum of governance modes and its innovative forms (e.g., Sabel & Zeitlin, 2008, 2010a; Tömmel & Verdun, 2009a, Héritier & Rhodes, 2011). Yet salient issues remained under-researched, particularly the power dimension of EU governance (Torfing et al., 2013, pp. 48–70).