Sources of Evidence of International Law


This paper explains to the to the Chief justice of Germany, who has been appointed to sit on the Bench of the International Court of Justice as an ad hoc judge in the case X, the sources and evidence of international law needed to deal with the mass of diverse materials submitted as part of the written readings.

Sources and evidence of international law

The most important source of international law for centuries was customary law, evolving from the practice of states. In recent times attempts were made to codify international law and the conclusion of many multilateral treaties. But Customary Law has still retained it’s predominance over treaty law or other sources in many areas, such as for example, state immunity, or state responsibility[1]. The State of the International Court of justice has manifested some of these tendencies in a codes:

Art. 38 states that when settling disputes, the court shall apply: international conventions, international customs, general recognized principles of law, and other judicial decisions and teachings. In order for the court to apply any asserted rule, it must be shown that the rule is the product of one or more of 1 to 3. All of the first three are of equal authority, thus the possibility of conflict exists.

I. American Journal of International Law

Most important role of legal documents and commentaries is collecting data necessary to establish and explicate rules drawn from international conventions, customs, and general principles of law. The distinguished American Journal of International Law[2] has been published quarterly since 1907. It features articles and editorials, notes and comment by preeminent scholars on developments in international law and international relations. The Journal contains summaries of decisions by national and international courts and arbitral or other tribunals, and of contemporary U.S. practice in international law. Each issue lists recent publications in English and other languages, many of which are reviewed in depth.
The Journal is indispensable for all professionals working in international law, economics, trade and foreign affairs. Therefore the Chief Justice of Germany can use the American Journal of International as a reference to obtain different stances in literature and previous decisions made by the organisations of international law.

II. Report of the International Law Commission

The International Law Commission (ILC), established in 1947 by the United Nations[3]. It’s a body of thirty-four (originally 15) international lawyers elected by the United Nations General Assembly for a five year term. The members of the ILC, who serve in their individual capacity, are supposed to represent the world’s general legal systems. The ILC is not only entrusted with the codification of international law, but also with the progressive development (that is, the drafting of rules on topics where customary law is non-existent or insufficiently developed); in practice the distinction between codification and progressive development is often blurred. Special rapportuers are assigned to propose work programmes and draft articles chosen by the Commission itself or referred to it by the General Assembly. Sometimes the Commission seeks to codify the law, not by preparing a draft convention, which may be later incorporated into a later binding multilateral agreement, but simply by summarizing the law in a report to the General Assembly. Such reports are not binding in the same ways as treaties, but they do constitute valuable evidence to customary law. The commission members base their work on extensive research and on an attempt to ascertain and reconcile the views of the member states of the United Nations (for example, by circulating questionnaires and by inviting states to comment on their draft reports – the same procedure is followed during the preliminary work on draft conventions). The effectiveness of the work of the ILC has more recently been called into question by some of it’s own distinguished members[4], and with the regard to the new topic under consideration its working methods may require adjustment to meet acceptance of drafts it produces by the majority of states. However, it is notable that the ILC managed to respond to the request of the General Assembly and complete its draft on the Statute for an International Criminal Court within the short period of 1992 to 1994. In any case, a report of the International Law Commission is definitely a reliable source for the Chief Justice to get some background on the issue discussed. Notable is that the Report should be regarded are not binding, and therefore should be used as a general consultation to the case.

III. Treaty between the two parties

A treaty, or convention as called by the International Court of Justice[5], is a deliberate act that creates international law, and reveals what states are willing to do. Treaties can be the result of compromise, bargain (rights traded for rights), or may be peace treaties made under the compulsion of war. Law making treaties may codify, define, interpret, or abolish existing customary or conventional rules of international law or create new rules. Nations exercise their sovereign rights when they enter into treaties. They also derogate from their sovereignty when they do so. There are Four Major Rules of Interpretation First, intentions of the parties are of paramount. Secondly, specific prevails over general. Thirdly the practices of states should not derogate from treaties. Fourthly, bilateral treaties are like contracts because they create legal obligations that prevail over general international law.

The Vienna Convention codifies the rules of treaties, and only deals with treaties. Article 2(1)(a) treaty means an international agreement concluded between States in written form, and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation. Article 6 states that every state has the capacity to conclude treaties. Article 7 states that only a person who has full powers could sign a treaty on behalf of the state. Heads of state, heads of governments and Ministers of Foreign Affairs are all considered to have full powers.

Next to Customary law, treaties will be one of the most important sources of international law, that he can refer to, when pre-judging the case. You should note, that both are treated equally Since treaties are binding, and most States don’t break them in their own interest, they can be used as a solid piece of evidence. The treaty will give the Chief Justice a good base on what the two parties have agreed on before. Then he will see why the two countries are in dispute over part of the treaty, or any other legal issues. The different stances from the Law Officers will surely give him the two sides to the story.

IV. UN General Assembly resolution

The idea of the United Nations was to get the major allies to act immediately in the face of aggression. Three functions of UN are collective security, maintain peace, and economic cooperation. Resolutions are brought upon through the General Assembly (Art. 19 – 22). All member states have a seat and 1 vote. Most of the work is done in committees. Most votes (Art. 18) require simple majority, some require 2/3. Most Resolutions made by the General Assembly are to discuss and recommend and not to bind, but this point is highly debated[6]. The General Assembly, the SC and other organ can request an opinion from the ICJ under Chapter 9 of the charter. But although General Assembly resolutions are not binding they can have important legal effect. They may be evidence of customary law, or of correct interpretation of the United Nation Charter. A resolution condemning a state for breaking international law is a useful means of putting pressure on a state to reconsider its position. There is also often a conflict over whether the UN organization or the non UN organization has jurisdiction over a matter. Until recently, the major activities of the UN had little to do with peace and security. Basically this doesn’t matter in our case, since the Resolutions are not binding, and are to give the Chief Justice an overview of the subject, and even a recommendation on how to judge. Since the General Assembly is one of the largest Institutions the importance of their work is significant. In combination with the report of the International Law Commission and the opinions of the two law officers, are of the highest importance to the Chief Justice of Germany.

V: Decision of the Supreme Court

Decisions of the Supreme Court of one of the countries (in Germany it’s the Bundesverfassungsgericht) are entitled to make judicial decisions, although there is no stare decisis. Domestic judges in common law jurisdictions don’t make pronouncements that are legally binding to the municipal system. Then again, many judgements of the different Supreme Courts will influence the decisions of the International Court of Justice. But in the end it does not have affect like other sources (e.g. common law). Therefore the Chief Justice might want to have a look at the decisions of the Supreme Courts, but should save his energy for the more important sources explained in this paper.

VI. Opinion of the law officer

A law officer of one of the two parties is an important source, since it makes clear what each party actually wants. The law officer reviews, and evaluates the case for his client in the bounds of the laws, sources, and pieces of evidence. He then gives an opinion on the subject, and prepares it for the hearing in front of the International Court of Justice. Once submitted the Chief Justice, and other members on the Bench of the International Court of Justice, can refer to it to get a better understanding of the case. If it wasn’t for this source, then the case could neither be prepared or heard, since none of the participants would be able to judge it on the various legal aspects of the case. Therefore this is one of the important basic sources, especially for an ad hoc judge.

VII. Preceding decision of the ICJ

The ICJ and its predecessor the ‘Permanent International Court of Justice’ are often referred to together as ‘the World Court’. The IJC, seated at the Peace Palace in The Hague, is one of six principle organs of the United Nations, but it has a special position as an independent court and is not integrated into the hierarchical structure of the other five organs[7]. Its Statute, which resembles the Statute of the PJIC, is annexed in the United Nations Charter, so that all members of the United Nations are automatically parties of the Statute. The Court has a double function: first, to settle legal disputes submitted to it by states in accordance with international law, and secondly, to give advisory opinion on legal questions referred to it by international organs and agencies duly authorized to do so.

Art. 92 gives Legitimation the International Court of Justice. Through Art. 94 the decisions of the Court are binding[8], and are enforced. The court functions according to its own Statue, which is annexed to the Charter. The International Court of Justice is composed of 15 judges, and the five permanent members also receive a judge. Judges are selected to ensure that there is geographical representation Judges are elected by General Assembly, and serve for nine years, the bench changes every three years. If a state appearing before the Court does not have a judge of its own nationality at the Court, it may appoint an ad hoc judge like in this case. The institution on an ad hoc judge is a survival of the traditional method of appointing arbitrators, and may be necessary to reassure litigants that the Court will not ignore their views; but it is hard to reconcile with the principle that judges are impartial and independent, and are not representative of their national governments. In General judgements of the Court are binding (as are the judgements of all international courts and arbitral tribunals). Article 94 of the United Nations Charter authorizes the Security Council (SC) to ‘make recommendations or decide on upon measure to be taken to effect on the judgement’. In addition to its power to decide disputes between states (contentious jurisdiction) the Court also has a power to give advisory opinions (advisory jurisdiction) Preceding Decisions of the International Court of Justice of the are not binding, but the Court relies heavily on judicial precedent cases, and follow the doctrine known an jurisprudence constante, rendering decisions that are sequentially consistent. This is an important piece of evidence to the Chief of Justice from Germany, since he can refer to past cases, maybe even read further details in the American Journal of Law, and therefore base his decision on the doctrine of jurisprudence constante. Interesting for him to know is, that the decision, that he makes will bind one of the parties. The enforcement can be achieved by laying embargos on a state, or is severe cases even use force to obtain that the decision is actually followed.


Concluding is to be said that all of the sources and evidence described above, are quite important to get a general picture of a case. They are like parts of puzzle, and when put together, give the Chief Justice a solid base to judge on. Of course not every piece of evidence weighs in importance, than the other. Treaties and customary law are in fact the most important sources of international law. But what would they be without the interpretation through the International Law Commission? How could international law be taught and have a chance to live from it’s diverse opinions, if it wasn’t for the American Journal of International Law? How could a solid judgement on the issue be made, if there weren’t the decisions of different supreme courts or the ICJ itself. Wouldn’t a judge be thankful for an resolution by the UN’s General Assembly giving him advice, or even the opinion of a Law Officer, who has looked into the legal issue of the Case?

As we look at the international sources of law, it becomes evident, that they are connected to each other. I would think as the international law being a tree, and the different sources being it’s branches. International Law lives from it’s sources, and depends on them like no other field of law, that I have studied. Over the years we should expect international law to become even more codified as it already is, therefore making it’s interpretation much easier.

Especially in the last years international law has become more and more of an issue to not only the broad society of law, but also the public. The media has addressed has finally made the citizens of this world, that Current Events like Golf War Crisis, The War of the Serbs on Croatia and Albania, are far more than a news story told on the news, and are not only subjects concerning the Middle East or Eastern Europe. Those are first of all Interstate related problems, that affect the peace of the world. But even more, as the media is finally understanding, they are subjects of international law. One might now argue, that the UN resolutions in both Wars were not effective enough, and the responsible persons involved in the wars haven’t been convicted by the International Court of Justice, but doesn’t this exactly expose what international is all about. It’s a legal body bound to laws, and will only react in the rules it has been set. Those sources of law are the legal grounds that have been yielded.

Last but not least the whole field of international law has realized it’s objective for the future. First of all, the sources of international law have to be more codified. Second of all, the laws must be applied to a legal matter right away, especially if there is a need for it (this is codified, and should be used). Thirdly, all sanctions against a state should be upheld until the potential threat is over, and the ICJ should seek to convict any person, who has broke international law.

The reward will be, that the states of this world will respect the treaties and laws even more, and international law will become an even more important field of law to keep the justice in the world we live in


[1] Malanczuk p. 35


[3] Vallat p. 1208-16

[4] Sucharitkul p. 15-42

[5] Malanczuk p. 36

[6] Malanczuk p. 377

[7] Malanczuk p. 281

[8] Malanczuk p. 288