The article traces the development and judicial practice on the “friendliness” or openness towards international law. From a rather sceptical note in ajudgment dealing with the “Concordats” of the Länder, the Federal Constitutional Court developed into a generic term for the obligation to comply with international law, including the orientation and guidance of international court decisions for domestic law. The values of Article 1 (2) and Articles 24-26 of the Fundamental Law generally lead to a duty to observe international law in the practice of the Federal Constitutional Court and the specialised courts. Exceptions can only be considered in the case of violations of the Basic Law itself or in the case of a deliberate decision by the legislature against the application of a treaty obligation. In that case, they lead however to a duty to adapt the corresponding obligation at the international level.
