It is not surprising that works on aggression have abounded during the past several years. As the author of a recent noteworthy contribution to the subject has said: “The problem of aggression is … intimately connected with that of international security.” Our present-day society, which seeks above all to stabilize its precarious security, is therefore compelled to preoccupy itself with the problem of aggression. It may, perhaps, seem unprofitable to add to the numerous pages which have already been devoted to this problem. We propose to do so only because we believe that we have established the existence of serious gaps in the doctrine of the subject, and, what is of greater importance, in its practice. Everyone admits, more or less explicitly, that the problem of aggression is inseparable from that of the prevention of war. However, when it is a question of defining the relations of the two or of showing how the solution of the former influences the practical construction of the latter, we find either a complete silence or fragmentary and empirical solutions which lack even the merit of leading to satisfactory positive results.

The Treaty of Versailles came into force on January 10,1920. Many of the matters with which it dealt were not definitely settled but placed within transitional régimes to be liquidated by decisions of the Principal Allied and Associated Powers, by commissions, by plebiscites or by other procedures or events within periods of time stated with more or less definiteness. The maximum time specified for any of these transitional régimes was 15 years. That period applied to the Rhineland occupation and to the régimes of the Saar valley and Upper Silesia. In the first two of these instances the 15 years dated from the coming into force of the Treaty of Versailles. In fact the Rhineland occupation was voluntarily terminated long before 1935. The Saar plebiscite was held during 1935, resulting in the transfer of the territory to Germany.

The Convention of 1936 for the Suppression of the Illicit Traffic in Dangerous Drugs represents a further stage in the development of international criminal law.

There are estimated to be 2,077,000,000 people now alive at a given moment on the 51,104,000 square miles of the continents, subcontinents and islands which constitute the earth’s inhabited land surface. They make extensive use of the 144,478,000 square miles of the world’s water area. Within the past century the living generations have come to control the entire surface of the earth with substantial completeness through the mechanisms of society which they have created; but they do not even yet utilize its land areas fully.

If one were to fly along the Rio Grande downstream from the city of El Paso, Texas, one would see stretching ahead for almost one hundred miles the construction works of an artificial river channel designed to replace the tortuous and meandering course of the old river. The rectification of rivers for purposes of flood control and general stability is an interesting but not a novel application of hydraulic engineering. This particular rectification project, however, enjoys the distinction of involving an international stream. One need not suggest the number of complex questions which must inevitably arise between two States undertaking to modify in this way a common arcifinious frontier. The background and development of this international plan, together with the treaty formulated to provide for and regulate the execution of the project, constitute a most interesting and unique example of contemporary international cooperation.

It is apparent that an examination of the development of the Italo-Ethiopian dispute before the League of Nations which does not consciously take into consideration the political motives from which the conflict arose and by which its course was dictated must remain largely incomplete and to that extent misleading. In the present instance, however, the exclusion of such considerations is not only dictated by the necessity of compressing within reasonable limits an account which might otherwise unduly tax the patience of the reader, but is also suggested by the belief that an inquiry into the operation of the League before and during the crisis of that conflict might in and of itself prove desirable.1

The so-called “neutrality laws” of the United States are statutory provisions, a part of the penal law of the United States, and should be clearly distinguished from the obligations imposed upon the United States by interyt national law. They may be regarded as an instance of the enforcement of international law by municipal law in the United States, and originated in the endeavors of the administration of President Washington to discharge the duties owed by the American Government as a neutral nation during the war between England and France in 1793. They punish criminally the commission of acts forbidden by the law of nations. As was well said by the Joint State and Navy Neutrality Board in 1916, “The doer of the wrongful act is accountable only to the United States, while the United States is itself accountable to a foreign government for the commission of the act. In this respect the neutrality laws differ from ordinary penal statutes, because the prohibited acts affect the international relations of the United States in addition to any effect they may have upon domestic tranquillity and order.”

The protection of unhampered and free exercise of the diplomatic function was recognized as one of the fundamental purposes of the law of diplomatic immunity in the Havana Convention of 1928, and in the Draft Convention of the Harvard Research Committee, 1932. The idea is not a new one—it has long been considered necessary that the channels of intercourse between States be made secure. Even before the political institutions of man began to play an important role in the life of peoples, nations or tribes recognized that it was necessary to treat with each other and guarantee security to messengers in order to advance their mutual interests. The history of the juristic philosophy of diplomatic immunity indicates that there are three periods of development in which the protection of the diplomatic function was deemed to be the purpose of the law, viz., (a) in antiquity, particularly in the universal law of Greece and Rome; (b) in the philosophy of the law-of-nature school, from the twelfth century to the seventeenth; (c) in the precedents of the modern Statessystem and the views of positivist writers, especially since the seventeenth century

In view of the increased interest in the problem of finding a legal definition for “war” or the “state of war” it seems worth while to consider briefly the hitherto rather neglected contributions to the subject by American and English courts. The problem of defining war has been effectively treated from several other viewpoints, but these English and American cases are worth examination for the further light they may shed on the fundamental questions involved. The fact that these decisions were in part prompted by the necessity of interpreting the phrase “war” or “state of war” in domestic statutes and that in all cases it is merely the voice of a national court speaking, need not detract from the value of the survey. The basis upon which judgment was rendered in most cases was (or at least was asserted to be) that of the law of nations, and, in the words of Chief Justice Marshall, the decisions of national courts “show how the law of nations, in a given case, is understood in that country.”

Written agreements record much that has been accomplished toward setting up a specific law between states. If international law is still essentially a customary law, with the weaknesses characterizing any such law, it is also true that through a process of transmutation many customary rules have at length been given more or less precise form through their inclusion in conventions. The opinion has been expressed that only by such a process will this law escape from being “a junk heap of antiquated and perverted forms of justice that has been brought about by the supremacy of power.” It is of course possible to have treaty provisions which merely incorporate by reference, and perhaps emphasize without stating, the rules generally accepted by civilized states.

The reference may be to international law in terms, or to the established body of the law by plain implication. Even if an existing rule is referred to for the purpose of waiving rights under it as between the parties, there is ordinarily an implied recognition of what has become established through custom.

The term “judicial assistance,” as used in international law, involves some still unanswered questions. Should it be used to embrace all the elements germane to the expedition of the business of courts of law, including not only procedural matters, but the execution of judgments and extradition; or relate exclusively to judicial assistance in civil proceedings? To avoid creating confusion by the use of a term suggestive of several meanings, in the following examination of the Soviet practice in this regard, the expression “cooperation in legal matters” is resorted to as an all-inclusive term.