Pandora oder Montesquieu?

The article analyses the PSPP Judgment of the German Constitutional Court in a broader international context. The first part focusses on the changing structure of International and European law due to the increase in international courts and treaty bodies and their decisions. It demonstrates that a process of vertical power delimitation between the international and national level is taking place and that national ultra-vires controls are an important part. The second part examines the question whether national ultra-vires controls are a risk for the international rule of law or whether they are an important instrument in order to control international courts and treaty bodies and to enhance their accountability. It shows that a national ultra-vires control is generally an important instrument to control the international judiciary provided that it is a rule of law based control and there is no misuse. The importance of this section is that the article defines further requirements for a manifest transgression of competences and lists indications for a misuse of this doctrine. The third paragraph examines the PSPP Judgement in detail and shows that the ultra-vires control performed by the German Constitutional Court meets the requirements for a rule of law based control. The article concludes that national ultra-vires controls are an important piece of puzzle in the current vertical power balancing process between the national and the international level.