The International Court of Justice is the principal judicial organ of the United Nations; it hears disputes between nations. The Court is composed of 15 Judges. The Statute of the Court provides that if a nation appearing before it in a case does not have a Judge of its own nationality as a member of the Bench, then that nation may nominate a Judge ad hoc who will sit as a member of the Court for that case.
In the Certain Iranian Assets case, Judge Joan Donoghue of the United States has recused herself thus rendering the USA without someone of its nationality on the Bench. The United States proceeded in August to nominate Professor Caron as its Judge ad hoc.