Structural equilibrium is the European Union’s functional, but for obvious reasons not nominal, equivalent of a federal equilibrium in federal regimes. It stands for rules and principles that govern the relationship between the constituent entities of the integration—Member States and the European Union as a supranational level—so that the integration can achieve its selected objectives efficiently while simultaneously preserving the Member States’ prerogatives. While the Treaty of Lisbon strikes a delicate balance between the Member States and the European Union, the post-Lisbon structural equilibrium might come as a disappointment for many. It neither lives up to the equilibrium of a constitutionalized federal state, nor does it meet the equilibrium of a confederacy. The Treaty of Lisbon in structural terms contains too little for a federation and too much for a confederacy. However, this is not a cause for regret, but rather another incentive to move European legal and political theory out of the federal-confederal box. Consequently, this Article argues that the Treaty of Lisbon puts up a structural equilibrium of its own kind, which places European integration in the middle of a federal-confederal continuum. This Article qualifies European integration as a Union (Bund), a non-state, non-federal, and nonconstitutional pluralist entity, which preserves the essential autonomy of its Member States and the supranational level, the European Union stricto sensu, within a viable common whole in a manner achieved by neither federations nor confederacies in the traditional sense.