"European constitutional law" is a discipline newly formed starting from the so-called "common European constitutional law" deriving from the development of principles common to Member States and from the activities of various European institutions (including the Council of Europe and the Strasbourg Court). The common European constitutional law, together with its hermeneutic value, is also a community law source. The European constitutional law has a broader meaning, because it starts from an integrative methodological approach whereby the constitutional problems of the Union must be considered constitutional problems of each one of its Member States. Strictly speaking, the European constitutional law means the constitutional law of the European Union; while in a large sense it refers to the constitutional law of the different constitutional spaces that make up the Union, such as the European constitutional space, the national ones and the spaces of regional autonomies (as in the case of politically decentralized states like Spain, Germany, Italy). The tension and dynamism of the European constitutional law thus understood push towards the adoption of new methodological approaches that, without relying on a rigid separation between European Union constitutional system and national systems, take into account the recognition of a dialectical relationship between these systems.