How the Commission fills in the blanks of the European Semester

Since the onset of the crisis the EU has introduced new instruments of economic governance, at the heart of which is the European Semester. Scholars largely disagree on which institutional actor has come out as the winner from these reforms. This article attempts to contribute to this debate by examining how the European Semester has been enforced by the Commission since 2011. The main argument is that although the decision-making process during the crisis has been broadly dominated by member states, the Commission enjoys considerable discretion over the enforcement of the European Semester. This is explained by the incomplete nature of the contracts of delegation between member states and the Commission. As a case study, the article focusses on the Commission’s discretion in enforcing the Macroeconomic Imbalance Procedure and the reinforced Stability and Growth Pact, as well as in shaping the procedures of the Semester itself. At the same time, it is shown that the Commission uses its discretion very carefully, alternating between flexibility and rigidity.