... 1960, in New York, via Resolution 1514 (XV), the U.N. General Assembly adopted the Declaration on the Granting of Independence to Colonial Countries and Peoples. It affirmed peoples' right to self-determination, and further stated:
The subjection of peoples to alien subjugation, domination and exploitation constitutes a denial of fundamental human rights, is contrary to the Charter of the United Nations and is an impediment to the promotion of world peace and co-operation.
The history of this instrument -- including the choice of a declaration rather than a treaty, and a General Assembly rather than a Security Council resolution, and judicial citations to the declaration -- may be found here.
(Prior December 14 posts are here, here, here, and here.)