It is true of course, that we have no judicial precedent for the Charter. But international law is more than a scholarly collection of abstract and immutable principles. It is an outgrowth of treaties and agreements between nations and of accepted customs. Yet every custom has its origin in some single act, and every agreement has to be initiated by the action of some state. Unless we are prepared to abandon every principle of growth for international law, we cannot deny that our own day has the right to institute customs and to conclude agreements that will themselves become sources of a newer and strengthened international law. International law is not capable of development by the normal processes of legislation, for there is no continuing international legislative authority. Innovations and revisions in international law are brought about by the action of governments such as those I have cited, designed to meet a change in circumstances. It grows, as did the common law, through decisions reached from time to time in adapting settled principles to new situations. The fact is that when the law evolves by the case method, as did the common law and as international law must do if it is to advance at all, it advances at the expense of those who wrongly guessed the law and learned too late their error. The law, so far as international law can be decreed, had been clearly pronounced when these acts took place. Hence, I am not disturbed by the lack of judicial precedent for the inquiry it is proposed to conduct.
The events I have earlier recited clearly fall within the standards of crimes, set out in the Charter, whose perpetrators this Tribunal is convened to judge and punish fittingly. The standards for War Crimes and Crimes against Humanity are too familiar to need comment. There are, however, certain novel problems in applying other precepts of the Charter which I should call to your attention.
The Crime against Peace:
A basic provision of the Charter is that to plan, prepare, initiate, or wage a war of aggression, or a war in violation of international treaties, agreements, and assurances, or to conspire or participate in a common plan to do so, is a crime.
It is perhaps a weakness in this Charter that it fails itself to define a war of aggression. Abstractly, the subject is full of difficulty and all kinds of troublesome hypothetical cases can be conjured up. It is a subject which, if the defense should be permitted to go afield beyond the very narrow charge in the Indictment, would prolong the Trial and involve the Tribunal in insoluble political issues. But so far as the question can properly be involved in this case, the issue is one of no novelty and is one on which legal opinion has well crystallized.
One of the most authoritative sources of international law on this subject is the Convention for the Definition of Aggression signed at London on July 3, 1933 by Romania, Estonia, Latvia, Poland, Turkey, the Soviet Union, Persia, and Afghanistan. The subject has also been considered by international committees and by commentators whose views are entitled to the greatest respect. It had been little discussed prior to the first World War but has received much attention as international law has evolved its outlawry of aggressive war. In the light of these materials of international law, and so far as relevant to the evidence in this case, I suggest that an “aggressor” is generally held to be that state which is the first to commit any of the following actions:
(1) Declaration of war upon another state;
(2) Invasion by its armed forces, with or without a declaration of war, of the territory of another state;
(3) Attack by its land, naval, or air forces, with or without a declaration of war, on the territory, vessels or aircraft of another state; and
(4) Provision of support to armed bands formed in the territory of another state, or refusal, notwithstanding the request of the invaded state, to take in its own territory, all the measures in its power to deprive those bands of all assistance or protection.