International Law: A Comprehensive Overview

This article is intended to provide an overview to the people from various fields, about the international law and the structure of the its legal system.


Summarizing key principles of law in minimum words, provide students an overview that enhance further study of the lawful topics. This article is intended to provide an overview to the people from various fields, about the international law and the structure and principles of the its legal system.

The term ‘International law’, also referred to as Laws of Nations was first coined by Jeremy Bentham in 1780. In international law, each country is referred to as ‘state’. The modern system of international law is result of only the few hundred years, influenced by the contributions of various writers and jurists who worked between 16th to 18th century CE. They formulated some of the fundamental principles of international law. International laws include set of rules, agreements and treaties which are binding between countries. All countries surrender some of its authority and come together to make these rules binding, they believe that it will benefit their citizens.

It is an independent and unique system of law, existing outside the legal framework of a particular state. It is the body of law that governs the relations and conduct of sovereign states with each other, as well as with international organizations and private legal individuals. International law covers a wide range of topics, including trade, human rights, diplomacy, environmental preservation, and war crimes, laws of oceans, etc. 

This field of law is different from domestic laws of particular independent countries in many ways. Firstly, it is primarily based on the consent of states. States agree to be bound by international law through treaties, customs, and general principles of law. Secondly, it is enforced primarily through diplomacy and negotiation. There is no central authority to enforce international law on states. And thirdly, international law is constantly evolving, reflecting the changing needs of the global village.


It is generally accepted that the sources of international law are listed in the Article 38(1) of the Statute of the International Court of Justice (ICJ), which provides that the Court 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;

1. Treaties

The law of treaties is set out in the Vienna Convention of 1969. Treaties are written agreements between States that are governed by international law. Treaties are referred to by different names, including agreements, conventions, covenants, protocols and exchanges of notes.

Treaties can be bilateral (sign between two states), multilateral (sign between more than two states), regional and global. 

The procedures for how treaties becoming binding and enter into force, the consequences of a breach of treaty, and principles for interpreting treaties. The basic principle underlying the law of treaties is pacta sunt servanda which means every treaty in force is binding upon the parties to it and must be performed by them in good faith. The other important principle is that treaties are binding only on States parties. They are not binding on third States without their consent. However, it may be possible for some or even most of the provisions of a multilateral, regional or global treaty to become binding on all States as rules of customary international law.

Now, there are global conventions, covering most major topics of international law. They are usually adopted at an international conference and opened for signature. Treaties are sometimes referred to by the place and year of adoption, e.g. the 1969 Vienna Convention. States who become a signatory to a treaty, it is not legally bound by the treaty but, when it deposits an instrument of accession or ratification to the official depository of the treaty, it means that a State expresses its consent to be bound by the provisions of a treaty.

If a State is a signatory to an international convention, it sends an instrument of ratification. If a State is not a signatory to an international convention but decides to become a party, it sends an instrument of accession. The legal effect of the two documents is the same. A treaty usually enters into force after a certain number of States have expressed their consent to be bound through accession or ratification. Once a State has expressed its consent to be bound and the treaty is in force, it is referred to as a party to the treaty. 

The general rule is that a treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in light of its object and purpose. 

2. Custom

International custom – or customary law – is evidence of a general practice accepted as law through a constant and virtually uniform usage among States over a period of time. Rules of customary international law binds all States. The State alleging the existence of a rule of customary law has the burden of proving its existence by showing a consistent and virtually uniform practice among States, including those States specially affected by the rule or having the greatest interest in the matter. 

Undisputed examples of rules of customary law are: –

(a) giving foreign diplomats criminal immunity; 

(b) treating foreign diplomatic premises as inviolable; 

(c) recognizing the right of innocent passage of foreign ships in the territorial sea; 

(d) recognizing the exclusive jurisdiction of the flag State on the high seas; 

(e) ordering military authorities to respect the territorial boundaries of neighbouring States; and 

(f) protecting non-combatants such as civilians and sick or wounded soldiers during international armed conflict.

3. General Principles of Law

General principles of law recognized by civilized nations are often cited as a third source of law. These are general principles that apply in all major legal systems. An example is the principle that persons who intentionally harm others should have to pay compensation or make reparation. General principles of law are usually used when no treaty provision or clear rule of customary law exists. 


International legal personality refers to those legal persons and entity on whom rights and

obligations are incurred under international law. Some of these legal personalities are: –

1. States

A State has the following features:

(1) a permanent population; 

(2) a defined territory; 

(3) a government; and 

(4) the capacity to enter into relations with other States, i.e. sovereignty 

Some exponents have also argued that a State must be fully independent and be recognized as a State by other States. The international legal system is a horizontal system dominated by States which are, in principle, considered sovereign and equal. International law is predominately made and implemented by States. Only States can have sovereignty over territory. Only States can become members of the United Nations and other international organizations. Only States have access to the International Court of Justice.

2. International Organizations

International Organizations are established by States through international agreements and their powers are limited to those conferred on them in their constituent document. International organizations have a limited degree of international personality, especially in relation to the member States. They can enter into international agreements and their representatives have certain privileges and immunities. The constituent document may also provide that member States area legally bound to comply with decisions on particular matters.

UN and its organ

The rules and regulations of the United Nations are set out in the United Nations Charter of 1945. Its main political organ is the General Assembly and its authority on most of the matters (such as human rights and economic and social issues) are limited to discussing issues and making recommendations. The Security Council has the authority to make decisions that are binding on all member States. It performs its primary responsibility of maintaining international peace and security. The main UN judicial organ is International Court of Justice (ICJ), which has the power to make binding decisions on questions of international law that have been referred to it by States or give advisory opinions to the U.N.

3. Nationality of individuals, companies, etc.

Generally, individuals are not regarded as legal persons under international law. Their link to State is through the concept of nationality, which may or may not require citizenship. Nationality is the status of being treated as a national of a State for particular purposes. Each State has wide discretion to determine who is a national. The most common methods of acquiring nationality at birth are through one or both parents and/or by the place of birth. Nationality can also be acquired by adoption and naturalization. Companies, ships, aircraft and space craft are usually considered as having the nationality of the State in whose territory they are registered. 

Doctrine of Diplomatic Protection

In international law, diplomatic protection (or diplomatic espousal) is a means, a state has right to take diplomatic and other action against another state on behalf of its national whose rights and interests have been injured by that particular state. Diplomatic protection, which has been confirmed in different cases of the Permanent Court of International Justice and the International Court of Justice (ICJ), that it is a discretionary right of a state and is not prohibited by international law. It can include consular action, negotiations with the other state, political and economic pressure, judicial or arbitral proceedings or other forms of peaceful dispute settlement.

In simple words, if a State A is injured by State B through unlawful conduct. It generally happens when a state carries out its activities outside their territory, in such cases, State A may make a claim against State B on behalf of its injured national. This is known as the doctrine of diplomatic protection.


As we reflect on the principles and practices of international law, we affirm its role as a testament to the power of dialogue and diplomacy in our quest for a better world. Through its institutions and agreements, international law invites us all to uphold the dignity of every individual and the unity of nations.

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