The United Nations Convention on Jurisdictional Immunities of States and Their Property: A Commentary

The law of state immunity has always rested on the dictates of municipal law and the judgments rendered by national courts. Its sources are particularly important for they reveal that although the subject matter of immunity is quintessentially international – from the point of view that it regulates the relations of states inter se – it has always developed by means other than a comprehensive multilateral treaty. And if custom is anything to go by, this has always been derived largely from the practice of domestic institutions, namely, immunity statutes, and local judgments. Of course, this is hardly surprising given that the first port of call as to the existence or absence of immunities in a particular case would have to be those courts charged with determining the issue at hand, unless of course the executive were to intervene, deeming the issue as not falling within the judicial remit.