Contemporary Southeastern Europe
The Good Neighbourliness Condition in EU Enlargement
Good neighbourliness is one of the most important principles relating to harmonious interstate relations. It primarily developed in international law around the idea of territorial sovereignty of states. The principle was further translated into an important accession condition in EU enlarge-ment policy. A violation of the good neighbourliness principle can lead to serious confrontations or military conflicts between states. Yet, the respect of the principle requires precise definition of its legal substance. As a paradox, the good neighbourliness principle has not been codified in international law. The lack of sufficient clarification of the essence of the principle potentially undermines the success of the Union’s engagement with it, threatening to lead to inconsistent interpretation and even to wrongful implementation of the good neighbourliness principle. The paper clarifies the legal basis of the principle in international law and traces the application of the corollary condition in EU enlargement policy where conditionality is deployed. It focuses on the application of the condition to settlements of bilateral disputes in the enlargement process. The paper concludes that the EU’s efforts to implement the good neighbourliness condition in ac-cordance with international law have failed so far.