Originally, the CJEU frames the preliminary ruling procedure as a dialogue between courts, aiming for uniform interpretation of EU law. However, it is an open secret that in addition to this dialogical function, the procedure is also used as an enforcement mechanism. Where national courts may lack the authority to effectively overrule Member State actors, they may invoke the authority of the CJEU via a preliminary reference to find the necessary support for their view. On the basis of 85 qualitative interviews and systematic case law analyses, this paper reveals the practical relevance of the preliminary ruling procedure’s enforcement function. It goes on to assess the effectiveness of this mechanism, and finds that the condition of relevance of preliminary questions and the varying specificity of the CJEU’s answers constitute significant limitations. In that light, it is assessed to what extent the CJEU may strengthen the enforcement function within the original dialogical framework.