The highest courts of those Member States which ratified protocol n° 16 could also ask the ECtHR for advisory opinions falling within the scope of EU fundamental rights. Therefore, a mechanism is needed in the eyes of the Court to regulate the relationship between these two mechanisms and to ensure the autonomy and effectiveness of the preliminary ruling procedure (paras 196 ff.).
Indeed it cannot be excluded that the entry into force of protocol n° 16 may effectively have negative effects on the role of the CJEU. Nonetheless, it must be taken into account that the opinions handed down by the ECtHR are non-binding. Furthermore, as also the Advocate General found (AG view para 140), such negative effects would not be an effect of the accession of the EU to the ECHR. Even without such an accession EU Member States who ratified the protocol can ask advisory opinions from the ECtHR.
Contrary to the Court’s view, this problem already finds its solution in the Treaties. Based on Art. 267 (3) TFEU the courts of last instance of the Member States are obliged to submit EU law questions in the framework of a preliminary ruling procedure to the CJEU. This obligation enjoys clearly primacy over the obligations of Member States as parties to the ECHR as they could result from protocol n° 16 (see also AG view para 141). Should a Member States‘ court of last instance nonetheless submit a question within the scope of EU law to the ECtHR without being entitled to do so under the acte-clair-doctrine, proceedings for infringement of the Treaties could be engaged against that Member State based on Art. 258 f. TFEU.