This article analyses the new challenges the ECB faces in implementing its monetary policy and asks to what extent judicial review can help address these.The ECB mandate provides no clear guidance for many of the ECB’s recent challenges, which include a sovereign bond market panic, technical limits to the efficacy of its tools, and questions concerning the environmental impact of its operations. For this reason, the ECB’s decisions suffer from democratic authorization gaps; it makes choices with far-reaching consequences for which there is no clear basis in the mandate. In this context, courts can either opt to accept choices made by the ECB, as the ECJ has mostly done, or, as the Bundesverfassungsgericht decided to do, itself weigh in on monetary policy. Neither approach, we argue, can improve the tenuous democratic legitimacy of the ECB in the absence of proper democratic guidance. There are, however, ample ways the Member States and the EU’s political institutions can provide the ECB with guidance on how to deal with its new choices.