This thesis examines the purpose of the preliminary ruling mechanism in the context of the rule of law case law. The preliminary ruling is an instrument of judicial cooperation used by the national judge to seek assistance from the Court of Justice of the European Union on the interpretation of EU law that has concrete relevance and necessity for the resolution of the pending case. After the Portuguese Judges, the rule of law case law often developed contrary to the purpose and spirit of the preliminary ruling procedure. That is because Article 19 TEU methodology oftentimes uses jurisdiction or the ruling on the substance as the basis for admissibility. This process has two implications. Firstly, when there is no substantial or procedural connection between the interpreted EU provision and ruling on the case, such interpretation loses the quality of a dialogue and elevates to the abstract constitutional revision of the laws of a Member State. Secondly, that process has a further implication that it often unduly burdens the procedural economy of the parties, as the resolution of their legal situations are often being delayed for months and years only for the preliminary ruling to take real effect on the national judicial architecture and not the legal position of the parties. The judgement in Miasto Łowicz explicitly and implicitly acknowledges the problematic aspects of the post Portuguese Judges case law and reinforces the purpose and spirit of the preliminary ruling mechanism. However, case law following the Miasto Łowicz judgement is not consistent. In the currently pending case of Hann Invest, the Court has a chance to take a bold standing on the matter and contribute the coherence and legal certainty on the matter. In light of the found implications, I consider how in its assessment of admissibility, the Court should reinforce it as a tool of cooperation rather than as a tool for revision.