»Every treaty in force is binding [...].« Article 26 of the Vienna Convention on the Law of Treaties hereby only mirrors a generally recognized rule of customary Public International Law: the fundamental principle of pacta sunt servanda. One of the sine qua nons of a democratic system is however the reversibility of political – and thus legal – processes. This tension between the stability of Public International Law and the flexibility of domestic legislature arose recently on the occasion of the ratification of the so-called Fiscal Treaty. The Federal Constitutional Court of Germany had to decide whether the principle of democracy (Art. 20 para. 1 of the German Constitution) imposes an option to suspend or terminate the treaty. The Karlsruhe Court stated that »at least« the provisions of »General Public International Law« allow a denunciation. It remained meanwhile unclear on which provision this conclusion may be based. The article examines in detail the possibilities to terminate or suspend the Fiscal Treaty in the context of the requirements stated by Public International Law, German Constitutional Law and the Law of the European Union. The provision of article 56 para. 1 lit. b of the Vienna Convention which allows to denunciate a treaty or to withdraw from it because of its »nature« will be focused as well as the articles 60, 61 and 62 of the Vienna Convention, which allow a termination of a treaty in cases of its fundamental breach and via the clausula rebus sic stantibus. Furthermore, the article sets out the procedural safeguards which intend to keep stability and flexibility in a fine balance.