During the process of the budgetary review the CAP faces its greatest challenge of its history: not only the (common) financing of the CAP, but the future of the CAP itself is at stake. It is obvious that the reform steps implemented so far – even though they have several forward-looking elements – do not result in a CAP sustainable on the long run. Further changes are inevitable. Basing our analysis on the theories of fiscal federalism and other political economy approaches, we try to answer the following questions. Is common financing of a reformed CAP justified? Can national co-financing be extended? Is it justified to keep the system of commonly financed direct payments?