International Court of Justice — Advisory jurisdiction — Requests by specialized agencies of the United Nations — Jurisdictional requirements — Requirement that agency be duly authorized — Requirement that question posed be a legal question — Definition of legal question — Political aspects do not necessarily preclude characterization of question as legal in nature — Political motives and implications irrelevant — Requirement that question arise within the scope of activities of the requesting agency — Role of the Court in considering request for an advisory opinion — Interpretation of question — Article 65 of the Statute of the International Court of Justice — Article 96(2) of the United Nations Charter — Agreement between United Nations and the World Health Organization (“WHO”) — WHO Constitution

International organizations — Specialized agencies of the United Nations — WHO — Competence to request advisory opinion regarding legality of using nuclear weapons — Whether question arising within the scope of the activities of WHO — Constitution of WHO — Interpretation — Approach to interpretation of constituent treaties — Nature of specialized agency — United Nations and specialized agencies as a coherent system — Position of WHO within the United Nations system — Principle of speciality

Treaties — Interpretation — Constitution of international organization — Approach to interpretation — Emphasis upon object and purpose of treaty — Subsequent practice

War and armed conflict — Nuclear weapons — Whether use of nuclear weapons prohibited by international humanitarian law — Protection of health and the environment in war and armed conflict