Who Pays the Piper calls the Tune? The implementation of the Union budget in the Institutional Framework of the European Union

The EU budget is an important tool for the attainment of the Union’s political and constitutional priorities. Despite its political significance, EU primary law sets only high-level principles as to the responsibilities for executing and implementing the Union budget. Against this background, this article provides a thorough analysis of the legal-constitutional principles guiding the budget implementation as set by the EU Treaties. Specifically, the article considers the European Commission’s responsibility under the current legal framework for implementing the Union budget. It, furthermore, distinguishes this responsibility from the respective role of the European Parliament and the Council as budgetary and legislative authority, and it legally qualifies typical practical cases of budget implementation. While the legislator enjoys certain leeway when defining what constitutes budget implementation in the context of a concrete legislative (basic) act, the article shows that there is a hard core of budget implementation which should remain reserved to the Commission. By combining the analysis of the legal framework with its practical implementation, this article contributes to establishing a clearer understanding of the role of the respective institutions in the implementation of the Union budget as well as of the primary law requirements for budget implementation.