The chapter analyses the fate of the constitutional principles of the European Macroeconomic Constitution after the recurring crises. The measures by the ECB stretched the principles to the limits and beyond. The objectives of internal market and price stability fared relatively well, but the principle of open market economy less so. However, the institutional choices and safeguards were all seriously altered, where the prohibition of central bank financing and Member States responsibility for sound fiscal policy were among the key principles that were the most fundamentally transformed. This, apart from the concerns about the constitutionality of individual measures, raises fundamental questions about the European Macroeconomic Constitution. The accountability and even legitimacy of the ECB relied on its unique position as a central bank of an economic constitution. It empowered it, gave it independence, but also constrained and controlled it. The chapter argues that the preconditions for an independent expert role of the ECB have been challenged by its measures and the inability of the judicial review to sustain sufficient boundaries. Consequently, the accountability and legitimacy of the ECB have been compromised, and with that also the rule of law with regard to the EMU is under threat.