European responses to the Eurozone crisis raise constitutional issues in both the European Union and its Member States. Furthermore, constitutional implications can be discussed at two levels, remembering the multi-layered nature of constitutions in general and the economic constitution in particular: in addition to explicit constitutional provisions and precedents, constitutions include a ‘sub-surface’ level of underlying principles, concepts and theories. In this chapter, we focus on doctrinal questions, related to ‘surface-level’ constitutional law and postpone ‘matters of principle’ to Chapter 6. Of course, these two levels neither can nor should be hermeneutically isolated from each other. The tougher doctrinal issues are, the more frequently legal argumentation must take recourse to the principles underlying individual provisions. Principles, in turn, can only be identified through the traces they have left in such ‘surface-level’ constitutional material as the Treaties or the case law of the ECJ, i.e. the constitutional court of the EU. It is perhaps more appropriate to speak of different emphases than two separate levels of discussion.

We shall argue that the Pringle judgment of the ECJ, together with the amendment to Art. 136 TFEU, which explicitly acknowledged Member States’ competence to establish a stability mechanism, have confirmed that significant changes in the macroeconomic constitution have occurred. We take these for granted, deferring to the weight the speech acts of the constitutional legislator and the constitutional court (ECJ) have in EU constitutional discourse. Yet, we feel free to criticise the argumentation in the Pringle ruling and the preceding view of AG Kokott, as well as in European Council Decision 2011/99 on the amendment to Art. 136 TFEU. Furthermore, we shall comment on the constitutionality of ECB action and thus enter a territory largely uncharted by constitutional scholarship. We shall also discuss the constitutional basis of reinforced economic governance, in particular the reach of Art. 136(1) TFEU in justifying specific Eurozone measures and the use of intergovernmental agreements to circumvent political obstacles blocking recourse to primary or secondary EU legislation.