Public International Law or International Law refers to the law of the nations. It could be defined as the body of legal rules, standards and norms that govern the relations between the sovereign states. It is the melting point of the jurisprudence of all the nations. They differ from municipal law or national law at some points and also do not possess much binding and strict authority as exercised by the national laws in the national sphere.

The jurisdiction of the International Law depends upon the States who have given their consent to follow and abide by it.
The term International Law was coined by Jeremy bentham, a famous English philosopher (1748-1832). According to him, international law is a collection of rules governing relations between states[i]. This original definition is given at a time when the concept of International organizations and individuals was not highlighted and so this definition excludes them.

Various definitions of International Law given by eminent jurists

According to Prof. L Oppenheim:

Law of nations of international law is the name for the body of customary and conventional rules which are considered legally binding upon civilized states in their course with each other.

According to J.L Brierly:

The law of nations of international law may be defined as the body of rules and principle of action, which are binding upon civilized states in their relation with one another.

According to Torsten Gihl:

The term international law means the body of rules of law, which apply within the international community or society of states.

With the passage of time the concept of International Law has developed to the extent that now it not only includes the subjects of war, peace, diplomacy, etc. but also talks about the human rights, space law, trade issues, international environmental issues, international organizations, etc. All the credit for the development of international law goes to the various sources which gave birth to it.

Sources of International Law

Sources of Law refer to the origin of laws. They are responsible for giving birth to the laws. They refer to the authority from which a law derives its force. As per the Merriam-webster[ii], source of law is something that provides the authority for judicial decisions and for legislation. These sources differ from nation to nation. For example, when we talk about the sources of Indian Laws, there are customs, precedents, statutes, etc. but for other nations, they may differ.

Sources of International Law

According to Article 38(1) of the Statute of the International Court of Justice [iii], there are following recognized sources of International Law:

1. International conventions, whether general or particular, establishing rules expressly recognized by the contesting states
2. International custom, as evidence of a general practice accepted as law;
3. The general principles of law recognized by civilized nations; and
4. 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.

Thus, it is clear that the juristic opinions are just indirect and subsidiary source of international law. The thing which is to be considered is that the provision of Article 38(1)(d) is subjected to the provisions of Article 59 which says that, The decision of the Court has no binding force except between the parties and in respect of that particular case.

Work of Jurists/Scholars contribute as a source of Public International Law

They are the fourth recognized source of International Law as per Article 38(1) of the Statute of the International Court of Justice. But the thing which is to be kept in mind is that the work of Jurists, writers, scholars and commentators acts only as a subsidiary means. If the Court while deciding a case does not find any treaty, legislative act, judicial decision, legal customs, general principles, etc. for the determination of that subject matter, the Court may resort to the opinion and work of these jurists and scholars to determine the rules of International Law. [iv]

Base of the work of jurists and scholars

The jurists or publicists base their work on the basis of legal philosophy, analogy and also by creating a comparison among the different legal systems of the world. Historical perspectives of different legal systems of the World are also analyzed by them for this very specific purpose. These scholar devote their whole life for the study of law and legal principles and therefore their work is also given due recognition as it is a result of great efforts of the great thinkers and experts. Their opinion on a particular subject is given an important place because of their valuable experiments and detailed study on that topic.[v]

Juristic work different from the opinion of judges

The opinion of jurists and scholars is required to be distinguished from the opinion of the judges. While judges are the one who decide the matter and their opinion is based on the basis of case, facts, evidences and laws in front of them, the opinion of the jurists are the result of their long work and in depth study on that particular subject matter which acts as a source of law for the Court.[vi]

Arbitral tribunals and national courts give much importance to juristic writings

The opinions of publicists are given great importance most of the time by the Arbitral tribunals and national courts. National courts most of the time are unfamiliar with the consistent and general international practice by states so they go for relying on the secondary sources as a substitute. On the other hand, International courts apparently might seem to make little or no use of juristic writings because of the practice of judgments is followed and they are also required to avoid an indivious selection of citations.[vii]

Great weight was given in earlier times

When there was not much development in the sphere of International Law and it was at initial stage only and there was lacking in the case precedents and treaty law was in its primitive stage, the work of Grotius, Vattel and others were given high weight by the American judges. Justice Story and Chanellor Kent are known for their great use of the writings of the foreign jurists.
It is even in the period of 1900s that the Courts of United States gave much consideration to the work of jurists and scholars. The evidence of it could be traced from the decisions laid down in the historic cases.

Contribution of Eminent Jurists

Hugo Grotius, Dutch jurist and scholar (1583-1645)

He was a major figure in the field of philosophy, law and political theory and he majorly contributed in the field of International Law during the period of sixteenth and seventeenth century. His work on the Law of War and Peace is considered to be the greatest contribution in the development of International Law.[viii] Together with Francisco de Vitoria and Alberico Gentili, Grotius is considered to be the founding father of public international law.

Emer de Vattel (1714-1767)

He was a great theorist of International Law during the time of eighteenth-century. He was a prominent figure in sustaining the practical and theoretical influence of natural jurisprudence through the Revolutionary and Napoleonic eras. Vattel contributed a lot to the source of contemporary wisdom on questions of International law in the American Revolution.[ix]

Francisco Suárez (1548–1617)

He emphasized that international law was founded upon the law of nature.

Alberico Gentili (1552–1608)
He was an Italian jurist. He was considered as the originator of the secular school of thought in international law. He got published three books on the Law of War, which contained a comprehensive discussion of the laws of war and treaties.

Paquete Habana and the Lola,

175 U. S. 677, 20 S. Ct. 290, 44 L. Ed. 320 (1900). [x]
It was observed in this particular case that International Law is part of their own law and must be ascertained and administered by the courts as having appropriate jurisdiction. When there exists no treaty and no other controlling authority in the form of executive, legislative act or any judicial decision, customs and usages of the civilized nations could be taken as a resort. As these jurists have devoted their whole life and created their work with hard labor, great efforts which also includes the contribution of great research and experience, their being well acquainted with the subject matter is obvious which do not require any sort of speculation and they could be treated as trustworthy evidence of what law really is.

Much less weight is given by the British courts to the opinions of jurists
The British courts on the other hand do not place much reliance on the opinions of the jurists as they lack in interest when it comes to giving recognition to a source, not belonging to their land.

West Rand Central Gold Mining Company, Ltd. v. The King,

[1905] 2 K. B. 391. [xi]
It was pointed out in this case that authority should be derived from a doctrine which is really accepted as binding between nations. Any source of International Law must be proved by enough evidence so as to ensure satisfaction when it comes to relying on them. Evidence must be given that the proposition put forward had been recognized earlier and had been acted upon by their own country. It should also be shown that they are widely and generally accepted. The mere opinions of jurists, only by reason of their being highly experienced, eminent or learned could not be blindfolded relied on and would not be sufficient unless they have received express sanction in international agreement or have grown as part of international law.

Conclusion
This is how the works of Jurists/Scholars contributed as a source of Public International Law especially in the initial phase when there were no case precedents and treaty law was in its primitive stage, no International organizations and mechanism, as it stands today were there. With the growth and development in the technology and the passage of time, their importance got diminished. Even at present they are a recognized source of law but only a subsidiary source.

Their authority also differs from nation to nation as we saw that how American laws still give them much importance as compared to the British law. These jurists/scholars have devoted their whole life for the study of law and legal principles. They created their work with hard labor, great efforts which also includes the contribution of great research and experience which is the reason that still they derive great authority.

End Notes:

1. https://www.britannica.com/topic/international-law#ref233494
2. https://www.merriam-webster.com/legal/source%20of%20law
3. https://legal.un.org/avl/pdf/ha/sicj/icj_statute_e.pdf
4. https://www.srdlawnotes.com/2017/03/sources-of-international-law.html
5. https://www.legalbites.in/sources-international-law/
6. https://scholarship.kentlaw.iit.edu/cgi/viewcontent.cgi?article=1854&context=cklawreview
7. http://www.ejil.org/pdfs/11/3/546.pdf
8. https://www.britannica.com/biography/HugoGrotius#:~:text=Hugo%20Grotius%2C%20Dutch%20Huigh%20de%20Groot%2C%20%28born%20April,greatest%20contributions%20to%20the%20development%20of%20international%20law.
9. https://www.libertyfund.org/books/the-law-of-nations/
10. https://www.law.cornell.edu/supremecourt/text/175/677
11. https://www.uniset.ca/other/cs5/19052KB391.html