This articles analyses the consequences brought about by the introduction of the Budgetary Stability principles, which are in part of the Monetary Union established in the Maastricht Treaty, in the Spanish law system. The article is divided into three parts: (1) the economic discussion on curbing debt and limiting the deficit and its impact in the EU monetary union; (2) the construction of the economic constituion in the EU and what this entails for Member States; (3) Spain as a case study of the difficulties of transferring a deficit/debt limitation “culture” in a highly decentralized country, with virtually no experience in limiting deficit and the debt by using constitutional (or treaty) measures. Ultimately, the Spanish case shows the difficulties of applying this legal framework to a “four level federalism” (EU, Member States, regions and municipalities).