The following is quoted from “Case Concerning Sovereignty over Pulau Ligitan and Pulau Sipadan
(Indonesia v. Malaysia) Application by the Philippines for Permission to Intervene Judgment of 23 October 2001” by the International Court of Justice at The Hague. It concerns the interjection made by the Philippines to be a party to the Pulau Ligitan / Sipadan dispute between Malaysia and Indonesia, on the basis of the historical claim of the Sulu Sultanate over Sabah.
Emphasis are my own.
13. The independence of North Borneo was brought about as the result of the expressed wish of the majority of the people of the territory in a 1963 election. The Secretary-General of the United Nations was entrusted under the Manila Accord of 31 July 1963 with the task of ascertaining the wishes of the people of North Borneo, and reported that the majority of the peoples of North Borneo had given serious and thoughtful consideration to their future and:
“[had] concluded that they wish to bring their dependent status to an end and to realize their independence through freely chosen association with other peoples in their region with whom they feel ties of ethnic association, heritage, language, religion, culture, economic relationship, and ideals and objectives.” (Quoted by the Representative of Malaysia to the General Assembly, 1219th meeting, 27 September 1963, Official Records of the General Assembly, 18th Session, UN Doc. No. A/PV.1219.)
14. In 1963, Britain filed its last report to the United Nations on North Borneo as an Article 73 (e) Non-Self-Governing Territory (Note by the Secretary-General, Political and Constitutional Information on Asian Territories under United Kingdom Administration, UN Doc. No. A/5402/Add.4 (4 April 1963)). Thereafter, the United Nations removed North Borneo from the list of colonial territories under its decolonization jurisdiction (see Yearbook of the United Nations, 1964, pp. 411-435, which omits North Borneo from the Committee’s list of territories), thereby accepting that the process of decolonization had been completed by a valid exercise of self-determination.
15. Accordingly, in light of the clear exercise by the people of North Borneo of their right to self-determination, it cannot matter whether this Court, in any interpretation it might give to any historic instrument or efficacy, sustains or not the Philippines claim to historic title. Modern international law does not recognize the survival of a right of sovereignty based solely on historic title; not, in any event, after an exercise of self-determination conducted in accordance with the requisites of international law, the bona fides of which has received international recognition by the political organs of the United Nations. Against this, historic claims and feudal pre-colonial titles are mere relics of another international legal era, one that ended with the setting of the sun on the age of colonial imperium.
16. The lands and people claimed by the Philippines formerly constituted most of an integral British dependency. In accordance with the law pertaining to decolonization, its population exercised their right of self-determination. What remains is no mere boundary dispute. It is an attempt to keep alive a right to reverse the free and fair decision taken almost 40 years ago by the people of North Borneo in the exercise of their legal right to self-determination. The Court cannot be a witting party to that.