Second, this demand would simultaneously mean that numerous agreements already concluded by the EU are already now in contradiction to Art. 344 TFEU as they do not contain such exception provisions (see AG view para 117).
Third, in this case also EU Member States would find themselves under an obligation under Art. 351 (2) TFEU to amend a number of existing agreements. As soon as two or more EU Member States – as in the MOX Plant case – form parties to an agreement with a dispute settlement mechanism and provisions that overlap in substance with EU law, the monopoly of dispute settlement under Art. 344 TFEU would thus be endangered and the relevant agreement incompatible with the autonomy of EU law
Fourth, it remains questionable whether the autonomy of EU law must really be secured by imposing on non-Member States that they have to expressly guarantee the respect of the monopoly on dispute settlement of the CJEU within the EU in the provisions of an international agreement. The suggestion made by the Advocate General is more convincing in this regard. It should thus be sufficient to start infringement proceedings based on Art. 258 f. TFEU against EU Member States if they settle their disputes before other international instances (AG view, para 118). As an additional measure to ensure the practical effectiveness of Art. 344 TFEU EU Member States could be obliged before the accession of the EU to the ECHR to declare with binding force under international law that they will not engage proceedings under Art. 33 ECHR whose object of dispute falls within the material scope of EU law (AG view, para 120).