CONCURRING OPINION OF JUDGES KOSKELO AND EICKE

1 . While we agree with the operative part and most of the reasoning of the present judgment we do have some reservations about paragraph 4 8 . In particular, we are unable to subscribe to the final sentence in that paragraph, declaring that the Czech Constitutional Court “could have decided the case in line with the Court ’ s case-law and on the basis of its own jurisprudence, even in the a bsence of legislative changes”.

2 . Even if this may strike some as quite a small reason for a separate opinion, it is important to us, as a matter of principle, to put on record our disagreement with the language adopted by the majority. In our view, the passage cited above raises a rather fundamental matter of principle, in that it implies a criticism by this Court of the domestic constitutional court ’ s application of domestic constitutional law. In this regard, we consider that the majority has unduly stepped outside the Court ’ s proper role.

3 . Under the Convention (Articles 19 and 32), the mandate of this Court is to ensure the observance of the Convention (including the Protocols thereto) by the High Contracting Parties, and its jurisdiction extends to all matters concerning the interpretation and application of the Convention and its Protocols. By contrast, it is not, in principle, the Court ’ s role to pronounce itself on whether the domestic constitutional organs have properly interpreted and applied domestic constitutional law, including whether the constitutional court has erred, as a matter of domestic constitutional law, in adopting a particular position in the impugned judgment. The Contracting States are required to ensure compliance with the Convention in accordance with their domestic constitutional order and the division of competences laid down therein. Whether one or other domestic organ was, in terms of the domestic constitutional order, under a duty to, and as a matter of domestic constitutional law able to ensure compliance with obligations arising from the Convention in a given context is not a matter to be determined by this Court.

4 . It is, after all, clear from this Court ’ s settled case-law that it is primarily for the national authorities to resolve problems in the interpretation of domestic legislation. The Court ’ s role is limited to verifying whether the effects of such interpretation are compatible with the Convention. That being so, save in the event of evident arbitrariness, it is not for the Court to question the interpretation of the domestic law by the competent national courts (see, inter alia , Károly Nagy v. Hungary [GC], no. 56665/09, § 62, 14 September 2017).

5 . The principle of subsidiarity, which emphasises the responsibility of the domestic authorities to ensure compliance with the requirements of the Convention and which is indeed of vital importance, does not in our view detract from but in fact underpins the above mentioned fundamentals of the Court ’ s role within the Convention system. The Court is competent for supervising whether the High Contracting parties (acting through their various domestic authorities) have lived up to the requirements and standards imposed by the Convention, but that task does not, nor should it, entail an authority (or ability) to supervise whether the respective constitutional organs have properly observed their functions and responsibilities within the domestic legal order. The issue of compliance with the Convention at the domestic level is distinct from the issue of the domestic division of competences and responsibilities in this regard, such as that between the legislative and the judicial branches. The latter, in principle, remains outside the Court ’ s remit of supervision.

6 . Furthermore, it is to be noted that the case of Habulinec and Filipović v. Croatia , cited by the majority in paragraph 4 8 , does not support any contrary view. After all, the relevant passage in that case was concerned with the issue of whether the applicants had complied with the admissibility requirement of exhaustion of domestic remedies. In such a context the Court, for obvious reasons, may have to examine quite closely and concretely the available system of remedies under the domestic legal order. The context in the present case, however, is entirely different, as this is a judgment on the merits of the case, thus dealing with the issue of whether the Czech Republic has complied with the requirements of Article 8 of the Convention. The internal attribution or distribution of responsibilities under the domestic legal order is not the object or focus of that determination. In so far as the judgment in Topčić-Rosenberg v. Croatia , also cited in the present judgment, may be read as supporting the approach adopted by the majority, we are not inclined, and certainly not bound, to follow the approach adopted by the Court in that judgment.

7 . Our reluctance to subscribe to what the majority state at the end of paragraph 4 8 is, furthermore, not only dictated by reasons of principle. Unlike a national judge well versed in the domestic legal order, this approach is also dictated by the limits of our own expertise. While some elements of domestic law may be sufficiently clear even for outsiders to understand without major difficulty, for instance where they consist of unequivocal statutory provisions, or correspond to generally recognised tenets of common legal principles, or where they consist of directly applicable EU law which is uniform in the whole of the Union, many areas of domestic law, including constitutional law and its interaction with the rest of the domestic legal order, are often complex and subtle, and it is therefore both difficult and inappropriate for outsiders such as ourselves to form or even less express an opinion thereon. While the statement at the end of paragraph 4 8 may or may not be correct as a matter of Czech constitutional law, as it is neither our task as members of this Court nor within our expertise to enter into those matters, we should not be expected to join in this kind of a statement, and therefore respectfully decline to do so.