Lesson 3: Principles of International Law: Sources of International Law

Why the Term “Civilized Nations” Was Used

When the ICJ Statute was drafted in 1945, many African and Asian states were still under colonial rule, so their legal systems were not fully represented.

The phrase “ civilized nations” reflected the historical context of the time.

Today, international law recognizes the equality of all states, regardless of region.

Judicial Decisions as a Source of International Law

Under Article 38(1)(d) of the ICJ Statute, judicial decisions are considered subsidiary means for determining rules of law.

This means:

Court decisions do not create binding precedents in international law the same way they do in common law systems.

However, they help clarify and develop legal principles.

Example: Head of State Immunity

Important cases discussed in international criminal law include:

Arrest Warrant Case (Democratic Republic of the Congo v. Belgium) decided by the International Court of Justice Decisions from the Special Court for Sierra Leone In the Charles Taylor case, the Special Court held that a sitting head of state cannot rely on immunity before an international criminal tribunal for international crimes.

Example entity

Charles Taylor – former President of Liberia prosecuted by the Special Court for Sierra Leone.

This decision helped reinforce the principle that there is no immunity for international crimes such as war crimes, crimes against humanity, or genocide before international tribunals.

Even though such decisions are not strictly binding precedents, they become persuasive authorities and guide future cases.

The Writings of Highly Qualified Publicists

Another subsidiary source under Article 38 is:

• “The teachings of the most highly qualified publicists of the various nations.”

This refers to:

• Books Academic articles Legal commentaries Expert reports These writings help courts interpret and develop international law.

Example of Influential Scholars One well-known international jurist is:

Antonio Cassese He made major contributions to:

• International criminal law Human rights law Development of jurisprudence at international tribunals.

His writings and judgments influenced institutions such as:

International Criminal Tribunal for the former Yugoslavia Special Tribunal for Lebanon Why Scholarly Writings Matter International law often has gaps because there is no global legislature.

So courts rely on:

academic research expert opinions legal scholarship Scholars sometimes also appear before courts as amicus curiae (friends of the court) to provide expert legal opinions.

Treaties and Domestic Law (Domestication)

How treaties operate domestically.

In some countries:

• Once a treaty is signed, it automatically becomes law (monist systems).

In others:

• The treaty must first be ratified and domesticated by parliament before it becomes domestic law (dualist systems).

For example, the Convention on the Rights of the Child becomes binding internationally once ratified, but domestically it may require legislation before courts can apply it.

Reservations and Optional Protocols

States sometimes accept treaties with reservations, meaning:

• They agree to the treaty except for certain provisions.

Example: Some states ratify the International Covenant on Civil and Political Rights but reject provisions relating to the death penalty.

Optional protocols are additional agreements attached to a treaty that states may join separately.

General Rule: Prohibition on the Use of Force The starting point is Article 2(4) of the United Nations Charter, which provides that:

States shall refrain from the threat or use of force against the territorial integrity or political independence of another state.

This means that invading another country is generally illegal under international law.

The Two Main Exceptions

There are only two widely accepted legal exceptions to this rule.

(a) Self-Defence Under Article 51 of the United Nations Charter, a state may use force if an armed attack occurs against it.

This principle was clarified in the case:

Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States) decided by the International Court of Justice.

The Court emphasized that self-defence is only lawful after an armed attack.

(b) Authorization by the UN Security Council The United Nations Security Council may authorize the use of force under Chapter VII of the UN Charter when there is a threat to international peace and security.

Examples include interventions authorized by the Council in various conflicts.