International Customary Law

Subject: Law
Type: Analytical Essay
Pages: 8
Word count: 2120
Topics: Injustice, Justice, Social Issues


Just like other concepts of the international law, the customary law lacks agreeable definition. However, many scholars define customary international law based on Article 38 of the Statute of the ICJ (International Court of Justice). ICJ defines international customary law as the “international custom, which is an evidence of the general practice of law.” The universality of this definition is because all members of the United Nations (UN) accept it. Notably, the ICJ is set under Article 59 of the international customary law and is the principal organ that is mandated with creating legal binding precedents about this law.

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On the other hand, the space law is defined as the body of law that governs the space-related activities. Space law, just like the international laws and treaties, comprises of various agreements, convections, and the UN General Assembly resolutions. Five international treaties associate with the law of space, and they include the outer space treaty, rescue agreement, liability convention, convention registration, and the moon agreement. In general, the law of space focuses on various matters that are of interest to humanity such as preservation of earth environment and space, liability for the destruction caused by space objects, space-related technologies, and international cooperation. 

Notably, there exists a relationship between the customary international law and the law of space. The emergence of the customary international law in relation to the space law is to offer the required state of practice and opinio juris by amending or invalidating specific provisions of the said five treaties under the space law. Besides, the customary law also contributes towards the revised interpretation of the legal obligations under the said treaties. This paper will explain the relationship between the customary law and space.

Principles of International Customary Law

The main sources of the customary international law are the general principles, which are recognized by all the member states. There are three main principles of customary international law that include law, treaties, and customs. In this case, the focus will be on the first principle, which is the law concerning the space law. The state practice and opinio juris form the foundation of the customary law (Andreas Wagner, 2012). Concerning the practice of states, the principle examines whether the member states are engaging in a normal practice. For instance, under the space law, the UN expects all the nations to protect the moon and other Celestial bodies for the importance of the humanity (Customary International Law, 9-70). Therefore, the practice must have the overall good of the humanity. Nonetheless, it should be emphasized that the principle of practice does not need to be universally followed so that it can be regarded as customary law, although the practice must have widespread acceptance.

Another principle that makes the customary international laws bind states is opinio juris. In this case, it is paramount to determine whether the practice of the member states is because of the legal obligation or due to a sense of courtesy or moral obligation. Another important key principle that is covered in this topic is that of jus cogens norms, which are peremptory norms in which derogation are not allowed. Jus cogen is regarded as a super-norm in the customary law and is limited to specific practices such as slavery and torture. In case of the space law, the norm can be extended to include the use of weapons of mass destruction in the outer space and other Celestial bodies. In conclusion, the norms or the principles of the customary law have been applied in various courts. An example in which the customary international law norms have been involved is the case of paramilitary activities against Nicaragua (Nicar vs. the U.S.A).  

Is an international customary law considered a primary source of Space law?

Various sources of the space law exist in which the international customary law is one of them. As noted earlier, customary law is an implicit agreement (treaty) between various states and is relevant to the Outer Space Treaty and other treaties. For instance, the Moon Treaty or the Moon Agreement is an example of the space laws, and it governs the activities of states while on the moon and other Celestial bodies.

Indeed, the Moon Agreement can be used to demonstrate that the international customary law is a primary source of the space law as it is in line with international laws and the United Nations Charter. Also, the ICJ Statute Article 38 explains the international customary law as a primary source of the space law based on opinion juris and State practice. 

Opinio juris

Opinio juris or an opinion of the law is the assertion that an action was carried out due to the legal obligation. Indeed, the space law has been passed with the aim of protecting the universe from being destroyed by human activities. To curb these destructive activities, member states have signed international treaties under the watch of the UN to ensure that the passed regulations are appropriately followed. As such, the space law becomes domesticated by the member state, which makes it a source of the customary international law. For instance, the United Nations Convention on the Law of the Sea is a domesticated space law that is aimed at managing the sea floors. Also, the Outer Space Treaty (1967) was first signed by the US, the UK, and the Soviet Union and it forms the fundamentals of the Law of Space. Just like other laws, this treaty has been ratified by other states and it requires members to be bound by the regulations. In this case, it can be concluded that international customary law is a primary source of the space law based on Opinio juris.

State practice

State practice is the uniformity of activities that are undertaken by various nations concerning the international customary law. As noted above, these practices should not be universally followed, but have different member states. For instance, Moon Treaty was passed by three nations, and later it was ratified by other UN member states. The notion behind the idea of the practice of states is to protect the universe against destructions (Peter Charles Hoffer, 2010). As noted in the above example, the Moon Agreement gives the member states a common practice that is intended to protect the space, the moon, and other celestial bodies. The fact that various member states follow these practices demonstrates that international customary law is a primary source of space law.

The Theory of Instant Customs

The concept of the instant customs is derived from the North Sea Continental Shelf Cases in which the ICJ diverted from the first notion of customary international development, which was based on opinio juris. In their views, the ICJ came up with a new course for the customary law that was based on the state of practice over a short-term benefit. The decision to adopt this new course was due to the increased rate of development in the modern global society. Therefore, it can be concluded that the choice of the practice of states as a source of international customary law is based on the ethical considerations as opposed to the legal backing. In light of this argument, this theory can be classified under the branch of ethics. The branch covers ethics and law of space, and it is focused on the human activities in the space.

Under this theory, “the usage prolong of the customary international law has no consequences if it is not prolonged or indeed it has no use if the practice is repeated.” Therefore, according to this theory, the success of the international customary law is not based on the existing regulations and laws (opinio juris), but on the need by the member states to act on the good of the society. An example of the application of this theory in the space law in the modern technological development is a case in which Judge Lachs cited the law of freedom of movement of substances in the outer space. However, the theory of instant customs has drawn numerous criticism from various observers based on the instantaneous nature of the approach. For instance, if international law has to be passed by different countries, there must be lobbying and putting structures in place to address the issue. On the contrary, this theory roots for a short-term measure to solve such a problem that could not be feasible in such a short period.

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North Sea Continental Shelf Cases

North Sea Continental Shelf Cases can be used for approving behavior without practice as demonstrated herein. An overview of the literature is that the North Sea Continental Shelf Cases set out a dual requirement that was used in the formation of customary law. The dual requirement includes the state practice (which is the object element) and opinion juris (subjective element). In this regard, the case formed the foundation that should be followed in establishing a state practice-representative participation and widespread acceptance. In addition, the NSCS cases highlighted the practices of the states whose aims and objectives are affected by the customs and especially those that are relevant to the formation of the customary law. In essence, these cases held that uniform and consistent practice are fundamental in demonstrating opinio juris. Lastly, NSCS cases disagreed with the theory of instant custom, as it dispelled the myth of a short-term factor in the formation of international law. Therefore, the bottom line in these cases is that behavior cannot be approved without practice.

Customary International Law in (State Practice-opinion)

This case will focus on the relation to customary international law and the state of practice. To start with, practice forms a fundamental law in the formation of the space law, hence leading to the international law. For instance, the signing of the Treaty of the Moon by the UK, the US, and the Soviet Union was intended to unify the practices of the developed countries in the moon and other celestial bodies. Indeed, these actions should not be universal, but must have widespread acceptance across the world. In this case, the Kyoto Pact about the climate change is an example of an international customary law that is widely accepted, but not binding all the UN state members. In addition, the treaty is not based on opinio juris in that a country is not legally bound by the set laws but by the ethical considerations. 

From the above analysis of North Sea Continental Shelf Cases, it can be established that practice of states is a major source of international law. Furthermore, it is clear that practice when repeated gains importance and significance in the formation of a particular law. Nonetheless, some human practices are detrimental to space and the outer universe; thus, they need to be addressed. For instance, the use of weapons of the space is an activity that is discouraged by various member states under the space law. In essence, the laws that are sourced from state practice are likely to be more effective than those that are based on established law.

What are Customs vs. Norms?

Norms are the expectations of a particular society. In the customary law, norms play a significant role in determining the nature and the formation of the space laws. In particular, the norms are an establishment of the practices of states that in turn form the sources of international customary law. On the other hand, the custom is an aspect of the customary law and forms the principle of custom. Indeed, along with the general principles of treaties and law, the ICJ, the UN, and other jurists as a general principle in the customary law also consider the custom. Although the two terms may seem related, there is a difference in that customs are practices that are traditionally passed from one generation to the next while norms are practices that have been adopted by a particular body of states. For instance, the violation of the space laws and that of the moon is a violation of the norms.

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All in all, this paper has discussed in depth the relationship between the customary international law and the law of space. In particular, the customary international law has been demonstrated to be a source of the space law through the practice of states and opinio juris. Moreover, the three basic principles of the customary international law, which include law, treaties, and customs, have been discussed as well. Besides, the contribution of the International Court of Justice and the United Nations in enforcing the space laws has been discussed where the North Sea Continental Shelf Cases have been used as examples. Finally, the difference between the customs and social norms concerning the international customary law has been explained.


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