In denying the Philippines' motion to intervene, the Court ruled that,
"... historic title, no matter how persuasively claimed on the basis of old legal instruments and exercises of authority, cannot - except in the most extraordinary circumstances - prevail in law over the rights of non-self-governing people to claim independence and establish their sovereignty through the exercise of bona fide self-determination.That bona fide exercise of self-determination already occurred in 1963, the Court further ruled, noting that the certification of this was done by no less than the United Nations:
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.I think the salient point is simply this: Self-determination trumps any historical title, no matter how persuasive or even valid!
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.