Nature, Scope, and Sources of International Law notes — Unit 1

The most fundamental question in international jurisprudence is whether Public International Law (PIL) is actually 'law' at all. Because there is no global parliament, no global police force, and no absolute global court, many jurists argued it is merely a system of ethics.

⇒The Denial: John Austin's View

John Austin (the father of analytical jurisprudence) famously defined law as 'the command of a sovereign, backed by a sanction.'

• Since the international system consists of equal, sovereign states, there is no 'superior sovereign' to issue commands.
• There is no sovereign police force to enforce sanctions if a state disobeys.
• Austin's Conclusion: International law is not true law. It is merely 'positive international morality'—rules of courtesy and ethics that states follow out of convenience, not legal obligation.

⇒The Rebuttal: Lassa Oppenheim's View

Oppenheim strongly defended PIL as true law. He argued that Austin's definition of law was too narrow and only applied to domestic criminal law.

• Consent, not Command: Law does not always need a sovereign commander. Customary law exists without a sovereign. PIL is based on the common consent of states.
• Sanctions Exist: While there is no global police, sanctions do exist in PIL (e.g., economic boycotts, UN Security Council military action, severed diplomatic ties).
• Oppenheim's Conclusion: International law is weak law, but it is undoubtedly true law.

Why do sovereign, powerful nations obey international law when they technically have the military power to ignore it? Jurists developed three main theories to explain the binding force of PIL.

⇒1. The Naturalist Theory

• Core Idea: International law is binding because it is derived from the 'law of nature'—higher moral principles of justice, reason, and divine will.
• Proponents: Pufendorf, Vitoria.
• Flaw: It is too abstract. States often behave based on brutal self-interest, not abstract morality. 'Nature' is subjective; what one state considers moral, another considers immoral.

⇒2. The Positivist Theory

• Core Idea: International law is binding strictly because states have consented to be bound by it. State will is supreme. If a state has not consented (via a treaty or custom), it is not bound.
• Proponents: Bynkershoek, Anzilotti.
• Flaw: If law is only based on consent, then a state can legally withdraw its consent at any time to commit atrocities. (e.g., A state cannot argue that it 'never consented' to the ban on genocide).

⇒3. The Grotian (Eclectic) Theory

• Core Idea: The middle path. Founded by Hugo Grotius (the father of modern International Law).
• Explanation: PIL rests on both. Much of it is based on the positive consent of states (treaties), but there is a baseline of natural law (reason/humanity) that binds all states regardless of their consent.

Unlike domestic law, where you look at a bare act passed by Parliament, finding the 'source' of international law is complex. The definitive, universally accepted list of sources is found in Article 38(1) of the Statute of the International Court of Justice (ICJ).

⇒The Hierarchy of Sources

The ICJ, when deciding a dispute, must apply the sources in the following strict order:

• 1. International Conventions (Treaties): Explicit agreements between states.
• 2. International Custom: General practice accepted as law.
• 3. General Principles of Law: Principles recognized by civilized nations.
• 4. Judicial Decisions & Juristic Teachings: As a subsidiary means for the determination of rules of law.

Treaties are the most modern, clear, and primary source of PIL. A treaty is an express, written agreement between sovereign states governed by international law. (Governed by the Vienna Convention on the Law of Treaties, 1969).

⇒Types of Treaties

⇒Pacta Sunt Servanda

The absolute bedrock principle of treaty law. It means 'Agreements must be kept'. Every treaty in force is binding upon the parties to it and must be performed by them in good faith.

Before modern treaties existed, Custom was the only source of PIL. Custom is an unwritten rule that has evolved from the long, historical practice of states. But not every habit of a state is a custom. A legal custom requires two incredibly strict elements.

⇒The Two Elements of Custom

• 1. The Objective Element (Usus / State Practice): The states must have actually behaved in a certain way consistently over a long period. The practice must be widespread, continuous, and uniform.
• 2. The Subjective Element (Opinio Juris sive necessitatis): This is the psychological element. The states must be acting that way because they believe they are legally obligated to do so. If states do something out of mere courtesy, political convenience, or morality, it is NOT custom.

This ICJ judgment is the absolute authority on how a practice becomes customary international law.

⇒The Core Issue

Germany, Denmark, and the Netherlands were fighting over how to divide the oil-rich seabed of the North Sea. Denmark and Netherlands argued for the 'Equidistance Rule' (found in a 1958 Treaty). Germany had not signed that treaty. Denmark argued that the Equidistance Rule had been used so much that it had become a binding 'Customary International Law' for everyone, including Germany.

⇒The Judgment of the ICJ

The ICJ ruled in favor of Germany. The Court laid down strict tests for custom:

• Passage of Time: A short period of time is not necessarily a bar to forming custom, provided the state practice was extensive and virtually uniform.
• The 'Opinio Juris' Failure: The ICJ found that while many states had used the equidistance rule, there was no evidence that they did so because they felt legally compelled to do so. They might have just done it for convenience.
• Result: Without opinio juris, there is no custom. Germany was not bound.

What happens if a dispute goes to the ICJ, and there is no treaty on the subject, and no historical custom exists? Can the ICJ just say, 'Sorry, there is no law, we cannot decide'? No. The ICJ uses 'General Principles'.

⇒The Concept

These are foundational legal principles that are found in almost every major domestic legal system in the world (like British Common Law, French Civil Law, Islamic Law, etc.). Because all civilized nations accept them domestically, the ICJ can import them into International Law to fill 'gaps' (lacunae).

⇒Examples of General Principles adopted by the ICJ

• Res Judicata: A matter once finally decided by a court cannot be reopened.
• Estoppel: A state cannot make a representation, have another state rely on it, and then go back on its word.
• Good Faith: Obligations must be performed honestly.
• Reparation: Breach of an obligation involves a duty to make reparations (pay damages).

Article 38(1)(d) lists these as 'subsidiary means'. They do not create new law; they only help prove what the law currently is.

⇒Judicial Decisions

• No Stare Decisis in ICJ: Article 59 of the ICJ Statute explicitly states that the decision of the Court has no binding force except between the parties in that particular case. The ICJ does not follow strict binding precedents like domestic High Courts.
• Practical Reality: However, the ICJ frequently cites its own past judgments to maintain consistency, making them highly influential.

⇒Juristic Teachings

The writings of 'the most highly qualified publicists' (famous legal scholars like Oppenheim, Grotius, Brownlie). In the 18th century, when treaties were rare, jurists practically created the law. Today, courts use their textbooks to understand complex customs.

This is the most powerful concept in modern International Law. Jus Cogens means 'compelling law'. It represents the absolute highest hierarchy of legal rules.

⇒The Absolute Ceiling

Normally, states can write a treaty to agree on whatever they want. But Jus Cogens norms are rules accepted and recognized by the international community as a norm from which no derogation is permitted. (Article 53 of the Vienna Convention on the Law of Treaties).

• Effect on Treaties: If two states sign a treaty that violates a Jus Cogens norm, that treaty is instantly void ab initio (void from the beginning).
• Examples of Jus Cogens Norms:
• 1. The prohibition of Genocide.
• 2. The prohibition of Slavery and Human Trafficking.
• 3. The prohibition of Piracy.
• 4. The prohibition of the Use of Force (Aggressive war).
• 5. The prohibition of Torture.

Example: If State A and State B sign a perfectly valid, signed, and ratified treaty agreeing to engage in the slave trade, the treaty is legally worthless and void because it violates Jus Cogens.

⇒Summary of Master Concepts

• Is it Law? Austin says no (no sovereign/sanction). Oppenheim says yes (consent and international sanctions exist).
• Article 38(1): The definitive hierarchy of sources applied by the ICJ.
• Treaties: Law-making vs Treaty-contracts. Based on Pacta Sunt Servanda.
• Custom: Requires State Practice (Usus) + Psychological belief of legal duty (Opinio Juris).
• Jus Cogens: The supreme, non-derogable norms of international law that destroy any treaty violating them.

⇒University Exam Tips for this Unit (Premium Advice)

• The 'Austin' Question: Examiners love asking 'Is International Law the vanishing point of jurisprudence?' This is a quote from Holland, supporting Austin. Structure your answer by first explaining Austin's rigid 'command/sanction' theory, then ruthlessly dismantle it using Oppenheim's modern realities of UN sanctions and state consent.
• Custom = Opinio Juris: Never explain Custom without explicitly writing the Latin phrase Opinio Juris. Cite the North Sea Continental Shelf case to prove that doing something for 100 years out of courtesy does NOT make it a law.
• Jus Cogens Supremacy: If a hypothetical question asks about the validity of a brutal treaty between two dictators, immediately invoke Article 53 of the VCLT and Jus Cogens to declare it void.