The ECB's secondary mandate requires it to support broader economic policies by and in the EU. How should the ECB deal with its many, potentially conflicting, objectives? To answer that question, this article combines normative and legal analysis with new archival sources, as well as analysis of ECB speeches and documents. A more important role for its secondary mandate fits well with the new, more political role of the ECB. However, the requirements that the legal text imposes on the ECB are paradoxical. While strictly binding, the secondary mandate is also highly indeterminate, and the ECB lacks the democratic legitimacy and legal competence to develop its own policies for pursuing the secondary objectives. To resolve this paradoxical situation, we propose that the specification of the ECB's secondary objectives should take place via high-level coordination with the political institutions of the EU.