Chapter 4 is dedicated to the concept of informality as a crucial legal concept for the understanding of trilogues. It begins from a twofold observation. First, the informal nature of trilogues is stated in black and white in a significant variety of legal instruments. Secondly, the role of legal scholarship is to make sense of that unequivocal characterization. Drawing on institutional theory, this chapter argues that informality is a full-blown concept of EU law, and it sets about defining its characteristics. To that end, it compares trilogues with two other informal bodies, namely the Euro Group and the Informal Council meetings. The core idea of this chapter is that the codification of informality translates into legal terms the intention of the institutions to protect certain spaces from an excessive penetration of legal normativity. This intention, in turn, is indicative of the desire to preserve those spaces for the emergence of powerful social frameworks where genuine exchanges among actors may occur; exchanges that should be conducive to compromise.

This chapter explores the role accorded to the principle of equality of Member States in the case law of the Court of Justice and national courts reviewing measures of financial assistance. At the same time, it investigates the extent to which the common interest, as the expression of the principle of solidarity, features as a consideration before those courts. The chapter opens with a brief description of financial assistance measures to gain a sense of how their versatile nature influenced judicial review. It then analyses judicial review of the European Stability Mechanism and the resulting Memoranda of Understanding at the national level in respect of access, remedies, and the interpretation of the principles of solidarity and equality. An analogous exercise is then conducted in respect of the EU courts. The chapter lastly reflects upon judicial interactions taking place between the EU and the national level and comments on the overall status of legal accountability in the EU judicial space.