This paper sets the scene for a series of analyses of the reform of the EU public procurement process. It does so by introducing the EU legislative process, its institutions and output from a theoretical perspective. It touches in particular on the role of the CJEU in this process and its influence on the actual outcomes of the legislative process, discussing the Court's discretion as well as its - constitutional and political - limits. The paper first briefly introduces the CJEU’s key role in EU polity-construction (1.) before focusing on the discussion of its role in the context of EU policy-making (2.), namely facilitating compliance with (2.1) but also shaping EU law (2.2), as well as the limits of CJEU discretion (2.3).