Although national courts of last instance are subject to a duty to refer under Article 267, paragraph 3, TFEU, the Court of Justice has significantly qualified that duty since Cilfit, thereby contributing to making failures to refer a widespread phenomenon. While reasserting a strict duty to refer is no realistic option in view of the workload of the Court, of the habits taken by national courts of last instance and also of the cooperative relationship that underpins the preliminary reference procedure, it was arguably imperative for the Court of Justice to alter its case-law in a way that would, at the same time, keep the flexibility offered by Cilfit, ensure that national courts of last instance do not unduly escape what formally remains of their duty to refer and devise suitable monitoring mechanisms and ultimately sanctions against unlawful failures to refer. The Court of Justice has recently embarked on that path by clarifying the scope of the still relative duty to refer and, above all, by coming up with an absolute duty for national courts of last instance to state reasons when deciding not to refer questions to the Court. While that duty raises new challenges for the preliminary reference procedure, this paper claims that it is a most suitable means to guarantee the effectiveness of the duty to refer. By modifying the place of the parties to the main processing within the preliminary reference procedure, the duty to state reasons does not only enhance the latter’s rights but it also heralds a new approach to the issue of the enforcement of the duty to refer.