“The requisite acquiescence on the part of individual states has not been reflected in formal or specific approval of every restriction which the acknowledged requirements of international justice have appeared, under the circumstances of the particular case, to dictate or imply. It has been rather a yielding to principle, and by implication, to logical applications thereof which have begotten deep-rooted and approved practices.”
[Page 9]
“It should be observed, however, that acquiescence in a proposal may be inferred from the failure of interested states to make appropriate objection to practical applications of it. Thus it is that changes in the law may be wrought gradually and imperceptibly, like those which by process of accretion alter the course of a river and change an old boundary. Without conventional arrangement, and by practices manifesting a common and sharp deviation from rules once accepted as the law, the community of states may in fact modify that which governs its members.”
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“States may through the medium of an international organization such as the League of Nations, itself the product of agreement, find it expedient to create and accept fresh restraints that ultimately win widest approval and acceptance as a part of the law of nations. The acts of the organization may thus in fact become sources of international law, at least in case the members thereof have by their general agreement clothed it with power to create and put into force fresh rules of restraint.”
“But international law is progressive. The period of growth generally coincides with the period of world upheavals. The pressure of necessity stimulates the impact of natural law and of moral ideas and converts them into rules of law deliberately and overtly recognized by the consensus of civilized mankind. The experience of two great world wars within a quarter of a century cannot fail to have deep repercussions on the senses of the peoples and their demand for an international law which reflects international justice. I am convinced that international law has progressed, as it is bound to progress if it is to be a living and operative force in these days of widening sense of humanity.”[568]
For the reasons stated by Lord Wright, this growth by accretion has been greatly accelerated since the First World War.[569] The IMT Charter, the IMT judgment, and C. C. Law 10 are merely “great new cases in the book of international law.” They constitute authoritative recognition of principles of individual penal responsibility in international affairs which, as we shall show, had been developing for many years. Surely C. C. Law 10, which was enacted by the authorized representatives of the four greatest Powers on earth, is entitled to judicial respect when it states, “Each of the following acts is recognized as a crime.” [Emphasis added.] Surely the requisite international approval and acquiescence is established when 23 states, including all of the great powers, have approved the London Agreement and the IMT Charter without dissent from any state. Surely the IMT Charter must be deemed declaratory of the principles of international law in view of its recognition as such by the General Assembly of the United Nations. We quote:
“The General Assembly recognizes the obligation laid upon it by article 13, paragraph 1 (a) of the Charter, to initiate studies and make recommendations for the purpose of encouraging the progressive development of international law and its codification;
“Takes note of the agreement for the establishment of an International Military Tribunal for the prosecution and punishment of the major war criminals of the European Axis, signed in London on 8 August 1945, and of the Charter annexed thereto and of the fact that similar principles have been adopted in the Charter of the International Military Tribunal for the trial of the major war criminals in the Far East, proclaimed at Tokyo on 19 January 1946;