The modern international law science puts forward a number of topical theoretical problems on whose solution the effectiveness of international relations regulation depends. The definition of the term «source of international law», its classification and legal validity is a problem, within which scientists and practitioners are required to come to common understanding of the legal validity essence of decisions made by international judicial institutions. The study is carried out with the use of integrative methodology: the views of the formal approach representatives are studied in conjunction with the philosophical and legal ideas. I.e. the positivist tradition, according to which today the sources of international law are classified into basic and optional
(special) ones, is complemented by the natural and legal understanding of the source of international law. Jusnaturalism as a type of law understanding enables analyzing both the form of existence and axiological content of IL source. The purpose of this article is to analyze the decisions of the International Court of Justice on maritime territorial disputes. Judicial decisions are confronted in two different ways: they are either considered as subsidiary means for the determination of rules of law, an argument based on the ICJ Statute itself, or as having the potential to be elevated at the sphere of formal sources. This controversy is highly interconnected with and affected by both the force of precedent and the role of international judges as lawmakers.
It is claimed, on the one hand, that precedent does not exist in the international legal order, since judgments are binding only upon the parties to dispute; on the other hand, practice has shown that past cases are highly cited by both the Courts themselves and the international community, and they can have a multiple role to play. The article devoted to the validity of decisions of international judicial institutions. The author is analyzing the decisions of the International Court of Justice on maritime territorial disputes, she proves that the quantity of judgments makes the new quality, confirming the trend of formation of public international law by judicial precedents.

Keywords: maritime territorial disputes, judgments of the International Court of Justice, «jurisprudence constantе»