The constitutional courts play a paramount role within the European judicial area and form a specific branch of the judicial network, including the Court of Justice of the European Union (CJEU) and the European Court of Human Rights. Within the European Union (EU) with its specific compound structure, in which national legal orders and Union law reciprocally influence, complement, determine and affect each other, national constitutional courts and the CJEU are not only assigned with the common task to enforce EU law, but also to preserve its limits, first and foremost the principle of conferral and the constitutional identities of the Member States. The respect for these limits is an essential prerequisite for the Member State’s participation in the EU and repeatedly enshrined in the Treaties. In order to be able to fulfil this common tasks all sides need to engage in sincere cooperation and a dialectic process, the potential of which must not be curtailed by hierarchical perceptions.Whereas the national (constitutional) courts are obliged to respect the CJEU’s authority to ultimately decide on the interpretation of EU law in principle, it is the CJEU’s obligation to take their referrals seriously and thoroughly adress concerns brought forward. The constitutional courts of the Member States are assigned with the constitutional responsibility to accompany the process of European integration in order to ensure that sovereign rights are only transferred in line with the respective provisions as well as that the excercise of competences respects the limits laid down in the Treaties and does not interfere with the constitutional identities of theMember States. It is of course again for the CJEU to review whether EU institutions, bodies, offices, and agencies act within their mandate in the first place including a quite large tolerance for different interpretations. To the extend the CJEU, however, fails to assume this responsibility, it is for the constitutional courts of the Member States to step in. The desirable success of the European integration largely depends on an orderly, sustainable and generally accepted process in the long run to which the network of constitutional courts can make a decisive contribution, provided it is designed and lived as a true cooperation among equals. In this regard it is not only necessary to intensify the joint efforts, but also to evaluate possibilities to enhance the involvement of the national courts, in particular the establishment of a reverse preliminary ruling procedure.