This article has been written by Sushant Biswakarma from Symbiosis Law School, Noida. It talks about the relevance of Customary International Law in today’s world and how it impacts inter-state relations around the world.

Introduction

Customary International Law refers to the international obligations that may not be formally written in conventions and treaties but still exist as a part of usual international practices.

Multiple states have a sense of legal obligation and hence, follow a general and consistent practice, which resulted in Customary International Laws.

For example, granting diplomatic immunity was an unwritten international custom until the Vienna Convention on Diplomatic Relations came into force in 1961, which made granting such immunity legally binding.

Recognition of Customary International Law

Customary International Law has been defined under Article 38(1)(b) of the International Court of Justice Statute as a “usual and general practice that is accepted as a law”. 

The ICJ (International Court of Justice) is an international judicial body and settles disputes arising between United Nations (UN) member states. Article 38 of the statute provides that the international customs and general practices of nations will be one of the sources of Customary International Law, and such Customary Law is one of the sources of International Law.

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Sources

There are two sources of Customary International Law, those are:

• General state practice – There must be a widespread and consistent state practice. Such practices are unwritten and mostly based on humanitarian principles and inter-state diplomatic relations.

For example- States granting refuge to refugees and asylum seekers because they feel a threat of life and liberty in their home state.

• Opinio Juris – It means ‘opinion of the law’. In simplest terms, it refers to what has been accepted as law by the States.

It is one of the elements that are necessary to set up a legally binding Customary Law. In order to establish unanimous customary practices in inter-state relations, the states codify some customary practices and accept them as laws. The states by way of ratification are bound to follow such law according to the doctrine of opinio juris.

However, with Customary International Law, the concept of opinio juris is highly unsettled and disputed because customary practices vary from state to state, making it difficult for the states to settle on a uniform practice that they are bound to follow.

Jus cogens

In human rights conventions, some rights are considered to be so important that they are non-derogable in nature. Such as- the right to life and liberty, etc. These rights are referred to as jus cogens norms.

The norms in International Law formed by the principle of Jus cogens can not be set aside. The Latin term jus cogens literally translate to ‘compelling law’. There is no need for any codification of such laws as these exist anyway. 

These are Customary Laws that are rooted in the principle of Natural Law. Any law in contradiction to it must be set aside. For example, laws that permit slavery, torture, genocide, crimes against humanity, etc., are contradictory of jus cogens and must be set aside.

However, it is to be noted that all jus cogens are der Customary International Law, but not all Customary International Laws can rise to the status of jus cogens. These are the basic and most important norms around which other laws must be made.

Codified and Uncodified Customary International Law

Not all Customary International Laws are codified, some are done so through various treaties and domestic laws. Whether codified or not, all Customary International Laws are recognized. 

Jus in bello, which is Latin for ‘law of war,’ flows from Customary International Laws and were uncodified until the Hague Conventions and Geneva Conventions. 

It is not practically possible for these conventions to codify each and every legal issue that could arise during the course of a war. Therefore, there is a Protocol Additional to the Geneva Conventions (Protocol I) that states that all legal issues regarding the armed conflict that are not covered by such conventions, will be governed by Customary International Laws, be it codified or uncodified.

Do Customary International Laws require ratification?

Any International Laws arising out of international conventions are not binding upon nation-states unless the countries consent to be bound by such laws by way of ratification.

But, Customary International Laws are norms that deal with Natural Laws and Humanitarian Laws and are so prevalent internationally that they need not be ratified in order to be binding. These laws do not require any state to expressly do something by using their resources, they are just required to not make any laws contradicting such laws.

However, sometimes a state may object to Customary International Laws, such states are not bound by them unless the laws are considered jus cogens. 

Laws are binding as long as expressed objection is not made, which gives rise to the principle of “silence implies consent”. This means that as long as no objection is made, consent to follow such laws is said to exist impliedly.

Ratification when Required?

There are various International Laws governing several nation-states, but there is no higher government that has the power to govern such states as citizens. Therefore, the common saying “international community is ‘anarchical’”.  

Unlike human beings, some nation-states are self-sufficient and need no one else for survival. They are in a position to turn down the benefits of cooperation with other states and the responsibilities of participating in the community under law.

This is a harsh reality and we are aware of it. Therefore, it has been a principle of International Law that the consent of states must be expressly given by ratifying a treaty or any other means in order to be bound by a rule. Customary International Law is an exception to this principle and is binding even without consent.

Bilateral vs Multilateral Customary International Laws

Customary International Laws can be either bilateral (practices between two countries) or multilateral (practices between more than two countries). This means that there may be only two countries recognizing a certain custom as Customary International Law, or there could be worldwide recognition of customs as Customary Law.

In the case of Portugal v. India, the existence of bilateral Customary Law was recognized for the first time by the International Court of Justice. In the instant case, the court held that the practice between two countries accepted by both of them as regulating their relations can be a basis of forming mutual rights and obligations between them.

In simple terms, it means that customary practice between two nation-states can later be recognized into bilateral Customary International Law.

Customary International Humanitarian Law

Customary international Humanitarian Law is a part of Customary Law, it refers to uncodified norms of public International Law, that governs the conduct and legality of armed conflicts which is why it is also known as the law of war.

Humanitarian law also flows from humanitarian principles and is aimed to cut the ill effects of war. It extends its protection to people who are not participating in or have ceased to participate in war and is trying to curb the methods of warfare.

War has existed among mankind as long as mankind itself has existed, so naturally, there has existed some principles and customs that one must follow during a war. Some of these customs and principles have been codified in the Hague Conventions and Geneva Conventions.

Even after the codification of such norms, it is impossible to codify each and every aspect of legal issues that might arise during a war, and hence, customary rules remain very much relevant in today’s armed conflicts.

Relevance of Customary International Humanitarian Law

There are multiple treaties on international Humanitarian Laws such as Geneva Conventions that have been universally ratified and are binding upon all, but not all such treaties have been ratified by every nation-state, and such laws are binding only upon the member states that choose to follow such law.

Customary international Humanitarian Law bridges this gap and even those states that have not ratified any humanitarian treaty are bound to follow certain customs during an event or armed conflict.

We are living in an era where we have more civil wars and wars for freedom than any inter-state wars. The treaties and conventions have recognized and codified laws regarding international conflicts, but the laws regarding armed conflict within a nation are not very developed.

Customary practices act as guiding lights in the absence of any proper, codified norms in treaties and conventions.

The University of Cambridge in 2005 published a study in Customary International Humanitarian Law, conducted by the International Committee of the Red Cross (ICRC) that identified 161 customary rules applicable in both international and national armed conflicts.

These rules were already in existence even though they were unwritten, various nations followed these uncodified rules. This shows that there is a mutual understanding between states and also within a state.

After looking at the study we can notice that, even without the introduction of Geneva Conventions of Hague Conventions, the states themselves have decided to draw a line on humanitarian grounds, and they tend to restrain from crossing such lines even during an armed conflict.

We can also conclude from the study that such un-codified customary rules become a general practice even without any express consent, which can later be recognized as Customary International Law.

However, this study has faced serious criticisms on the grounds that the methods of identifying Customary Humanitarian Laws were controversial. But, if we believe that the ‘ends justify means’ and the results of this study have helped us in a better understanding of the formation and importance of Customary International Laws.

Is Customary International Law crucial today?

The world had 74 independent countries in the year 1946, the number raised to 89 by the year 1950, and today there are 195 independent countries having their own sovereignty. Now, with the growing number of independent countries, it is getting harder and harder to follow a unanimous pattern of Customary International Law.

Codification and express ratification is required for every single norm to be binding these days. Diplomatic immunities were once an essential of Customary International Law and no codification of such was required, but, these days they are reinforced by bilateral agreements, investment insurance, and other ways.

We can observe that the pattern of states behaviour is changing drastically from a custom driven state to a rule of law. This introduces a new feature that tends to make the pattern more stable and reliable.

It is not that customary norms are getting obsolete, all International Laws are based on customary practices. Codification of such practices ensures a unanimous and uniform International Law.

However, most of the International Laws are based upon customary norms, the intent behind these norms are the same, they have just been codified for efficiency.

Uncodified Customary Laws are also important because the ambit of such laws are much wider, the codified laws are binding upon only those who expressly consent to follow them, but the Customary Laws based on humanitarian grounds are binding upon everyone, and all laws must be made in keeping Customary Laws in mind.

Conclusion

Customary International Laws have existed as long as mankind has existed, they are the basic norms that are mostly based on humanitarian grounds and principle of natural justice, no laws can be drafted in contravention with them.

With the change in time and technology, warfare among nation-states have decreased significantly, and on the other hand, trade and diplomatic relations between states have seen a drastic rise.

With the rise in trade and cooperation, no state is completely self-sufficient and even the most developed of the states depend on others for one thing or another.

Customary International Laws have played a huge role in establishing diplomatic relations between nation-states, but it is the codification of such norms and voluntary ratification by the states that changed the way they function and dramatically changed the international scenario.

Also, with the increase in the number of States, it is near impossible to keep up with un-codified norms and establish a uniform practice all over. Codification of such norms was very essential.

However, this does not in any way mean that Customary Laws have lost their importance. Customary International Laws have a much wider scope of applicability and are binding upon everyone. They are the basis of every international prevalent today and every new norm must still abide by such customs.

References

• https://repository.law.umich.edu/cgi/viewcontent.cgi?article=1638&context=mjil
• https://www.icj-cij.org/en/case/32
• https://ihl-databases.icrc.org/customary-ihl/eng/docs/home
• https://heinonline.org/HOL/LandingPage?handle=hein.journals/sljinl21&div=18&id=&page=
• https://nsuworks.nova.edu/cgi/viewcontent.cgi?article=1560&context=ilsajournal/
• https://digitalcommons.law.uga.edu/cgi/viewcontent.cgi?article=1385&context=gjicl

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