Material Breach of a Treaty on the Example of the Arbitration Agreement Between Croatia and Slovenia

Sa？etak This paper determines the existence of a material breach of the Arbitration Agreement between Croatia and Slovenia within the meaning of Article 60 of the Vienna Convention on the Law of Treaties of 1969, and thus the validity of Croatia's request to terminate the Arbitration Agreement. To be more specific, Article 60 of the Vienna Convention provides for the right to unilaterally terminate a treaty in the case of its material breach. Given that the existence of a material breach is a key condition for acquiring the right to unilaterally terminate a treaty, the notion of material breach is considered, with a particular emphasis on the criteria for material breach laid down in Article 60 of the Vienna Convention. On that basis, the paper analyzes whether Slovenia's actions, i.e. ex parte communication in the arbitration between Croatia and Slovenia represents a repudiation of a treaty or a violation of a provision of the Arbitration Agreement essential to the accomplishment of its object and purpose. Finally, the paper argues that Slovenia has materially breached the Arbitration Agreement within the meaning of Article 60 of the Vienna Convention