For its part, the Declaration states that accession “should be arranged in such a way as to
preserve the specific features of Union law,” and notes the existing “regular dialogue between” the CJEU and the European Court of Human Rights (ECtHR), which “could be
reinforced when the Union accedes to” the ECHR.
Though, these new Treaty provisions could not by themselves make the EU a contracting
party to the ECHR. To obtain that outcome, it was necessary for the EU to negotiate a
specific accession treaty with the Council of Europe. After a long negotiation process, this
accession treaty was agreed in principle in 2013. Opinion 2/13 concerned the
compatibility of that treaty with EU law.