The old political adage, according to which the budget is ‘politics in the form of figures’, still accurately describes the critical importance of the state budget for the exercise of political power. Therefore, the actions brought before the German Federal Constitutional Court, have repeatedly focused on questions regarding the constitutional limits of public debt. This thematic focus is hardly surprising, given the fact that the debt burden, which has been approved in a past or contemporary budget law is likely to limit the financial and, thus, political scope for any decision-making of the legislator in the future. The problems that high public debts entail for the future of constitutional democracies are not unknown in the other Member States of the European Union. Questions of this kind have not yet been brought to the attention of the Court of Justice of the European Union. The reason for this lies in the historical evolution of the financial constitution of the European Union and, in particular, in the specific division of competences in budget matters.