This chapter is intended to show how the RMT judgement of the European Court of Human Rights illustrates, six years after the leading case of Demir & Baykara, the remaining uncertainties and methodological blind spots of the ‘integrated approach’, according to which the Court is led to make use of ‘external sources’. Should such an approach be legally based on the ‘letter’ of article 31, §3, c of the Vienna Convention on the Law of Treaties or on the ‘evolutive and consensual’ interpretation of the ECHR? Should the use of ‘external sources’ as means for conventional interpretation remain ‘subsidiary’? Should the Court give more ‘weight’ to external sources resulting from a ‘concrete’ review of compatibility with fundamental rights? Could or should the integrated approach lead the Court, in the name of consistency and consensus, to a ‘levelling down’ of the conventional interpretation when the level of protection of the fundamental right at stake diminishes in the normative environment of the Convention? In the following discussion, these questions are addressed in the light of the recent Brussels’ Document on the Future of the Protection of Social Rights in Europe, laid down in the context of the Belgian Chairmanship of the Committee of Ministers of the Council of Europe. The proposed rewritten judgement, on its part, holds, contrary to the original ruling, that the United Kingdom has breached article 11 of the Convention.