The development of various aspects of the theory of modern international law sources has not only scientific, but also great practical importance. The identification of source patterns, as well as their interaction, provides the opportunity to understand the modern international law and evaluate its trends. It should be noted that the correct interpretation and understanding of the problem related to the sources of international law, can help receive the answers to such important practical and theoretical questions of general international law. These problems include the role, value and validity of resolutions, declarations and other instruments of international organizations; the role and importance of legislative decision-making organizations in the overall formulation of the norms of international law; the value of the contract in the process of creation of customs and universally recognized norms of international law etc. These and many other circumstances may explain the great interest which was shown to the aforementioned issue sources in the end of XIX century. In fact, this interest to the question of the indicated sources and their interaction is still growing.
Sources of international law are the forms of existence of international legal norms. The materials and processes out of which the rules and principles regulating the international community are developed apply to the similar characteristics of the sources of law in the general legal theory.
There are two main sources of international law, i.e. international treaties and international customs. Along with these primary sources there can be distinguished the acts of international organizations, conferences and meetings. However, these acts can be considered as the sources of international law only if they establish binding rules of conduct for the international organizations or other subjects of the international law. Besides, they must meet the requirements of norm-formation.
The 38-th article of the UN ‘Statute of the International Court of Justice’ states, ‘The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:
a. international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;
b. international custom, as evidence of a general practice accepted as law;
c. the general principles of law recognized by civilized nations;
d. subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.’ (United Nations 2012).
International conventions are agreement among the countries or other subjects of international law, which is provided in written form and contains the mutual rights and obligations, regardless of whether they are written in one or more instruments and whatever is its particular designation. One of the most significant international law conventions are the Vienna Conventions. The Vienna Convention of the Law of Treaties of 1969 contributes to the international law since it defines treaty as international agreement that is concluded between states that should be written and governed by international law (Murphy 2002). It is significant since affirms the right of every state to conclude treaties that it may have entered into. The Vienna Convention of 1986 extended the original definition of treaties: it included international agreements that involved international organizations as parties of the agreement. This convention was of great meaning and value because it emphasized the importance of a treaty being concluded by organizations that have appropriate authority to make treaties or by states. It also stressed the importance of the international law governing every treaty.
International custom is a source of international law as a result of prolonged repetitive usage, i.e. steady practice. It implies the traditional basis of custom recognition as a source of law. The formation of custom can be possible in the short time periods (D’Amato 1971).
The unilateral actions and acts of states are supposed to be the intermediate agents that determine the existence of the customs. They can act as a proof of acceptance of the rule of conduct as the custom. Such unilateral actions and acts include domestic legislative and other regulations. In order to confirm the existence of a customary rule, the international judicial bodies often resort to the references of the national legislation. The official statements made by the heads of states, governments and other representatives, including international bodies, as well as delegations to international conferences and joint declarations of states also serve a proof of existence of the customary rules and are ‘opinio juris.’
The formation of custom is not completed with the emergence of rules of conduct. Only the recognition of the rule as a law (‘opinio juris’) makes a particular rule of conduct the custom. Customary rules as a general rule have the same legal effect as the treaty ones.
The traditional elements that make up the international custom include:
- the duration of the existence of the rules of conduct and sustainability of practice compliance by several subjects of international law;
- tacit recognition of the rules of conduct as a mandatory standard.
However, the duration of practice to form a habit is not critical. Circumstances, affecting the formation of custom, may be so extreme that the custom may arise on the basis of a single precedent (Gaebler & Smolka-Day 2002).
According to the foundation documents (charters), the most of the recent inter-governmental organizations have the right to enter into international agreements as well as regulate international relations through the resolutions.
Acts of the international conferences include the agreements of the conferences, created specifically for the development of the international treaty, which was ratified and brought into effect. Acts of international organizations involve the acts of the General Assembly.
Currently, the provisions of the international treaties occupy the main place in the international law. It is caused by the following reasons:
1) the creation of common standards is the long process. Sometimes there are difficulties in establishing the precise content of the customary rules. The process of creating the conventional rule is not as long. Nevertheless, in this case the will of the subjects of international law is more pronounced;
2) the procedure for the contract conclusion and execution is developed and defined by the Conventions on the Law of Treaties of 1969 and 1986;
3) the contractual form provides more opportunities to match the will of subjects than any other form.
These and other factors are responsible for the increasing use of the contract creation process in the international legal norms. The agents of international law recognize the important role of treaties in international relations and recognize the increasing importance of treaties as the sources of international law and means of peaceful cooperation among nations.
In the XIX century, the works of outstanding scientists in the field of international law were often considered the sources of international law. Nowadays, importance of the doctrine of international law can not be underestimated since, in some cases, it helps explain certain international legal provisions, as well as the international legal position of states. However, it must be remembered that even the most outstanding work of the scientist can not be accepted by the International Court of Justice as a mandatory source.
The theory of international law determines three stages of the occurring of the international commitments:
1) the adoption of the text;
2) the establishment of authenticity of the text;
3) the consent to be bound.
Teachings of the most qualified experts in the field of law can serve only as aids to determine the exact content of the positions of international law agents in the application and interpretation of international law. The states and other subjects of international law while coordinating their will on the international rules of conduct can decide the form of implementation of this rule and also chose the source, in which these rules will be fixed. Thus, the states free to choose the form of consolidation of international legal norms (Murphy 2002).
Accordingly to the different levels of power, several types of international agreements and treaties are defined:
1) the international agreements (the highest level, concluded on behalf of the particular countries);
2) intergovernmental (concluded on behalf of the governments);
3) interagency agreements (concluded at the agency level).
By the number of the signing parties, there can be identified the bilateral and multilateral treaties. The bilateral agreements are signed by two subjects. The agreements can be considered bilateral if they are signed by single state from one side and a few states from the other side. The multilateral agreements imply the treaties among the variety of countries.
Contracts can be open or closed. Open treaties imply free entrance regardless of whether or not there is consent of the other of the participating states. The contracts are closed if the consent of the participants is the absolute condition of its accession. On the basis of the objects of control, the agreements can be divided into political, economic, scientific, technical, etc.
All of the above contracts are ones of the state as a whole, thus, it is responsible for implementation of their regulations. Therefore, in accordance with the international law, different types of contracts have the same legal force (International legal materials: current documents 1962).
The decisions of the International Court of Justice, as well as other international courts and arbitral bodies, refer to the judicial decisions like sources of international law.
In fact, the customary rules of international law are formed similarly to the conventional international legal norms in two steps:
1) the approval of the rules of conduct;
2) the acceptance of rules of conduct as international legal norms.
The recognition of the rules of conduct as the customary rules can be made both by the active and passive (abstaining from action) measures. The absence of protest against any act of international entities may also indicate the recognition of the legitimacy; consequently, these actions receive the force of the international legal norms.