摘要: In the previous chapter, it was shown that EU is a ‘multilevel system’, of which sub-national authorities are an integral part. The existence such ‘multilevel’ and ‘multidimensional’ requires development principles tools coordinating action different levels government. This explains why concepts as multilevel governance subsidiarity increasing in importance EU. Whilst most studies deal with this concept from political science or economic perspective, legal scholars use same notion descriptive formula illustrating role However, has never been studied concept, nor have its constitutional foundation, rationale consequences explored. For first time, chapter analyses EU, specifically perspective. It will be argued legal/constitutional principle stemming European ‘constitutional composite’. ‘procedural’ commands ‘method governance’ consisting involvement decision-making process implementation law/policy (Sect. B). way, contributes legitimacy to participation Member States activity C).