Concluding Part I of the book, this chapter summarises the main findings and updates the theoretical explanation introduced in Chapter 2. The key objective of Part I was to answer the following question: What determines variation in the level of conflict in EU budgetary politics? Chapter 2 put forward the argument that the institutional design of the decision-making procedure is a decisive variable in influencing the level of conflict. The empirical chapters revealed the high explanatory value of this argument and the detailed propositions that followed from it.