Legal Reasoning Questions for CLAT | QB Set 86 [Sources of International Law]

International law consists of rules and principles that govern relations between States and, in certain cases, international organisations and individuals. The principal sources of international law are generally identified in Article 38(1) of the Statute of the International Court of Justice (ICJ). These include international conventions or treaties, international customs, general principles of law recognised by nations, and judicial decisions and writings of highly qualified jurists as subsidiary means for determining rules of law.

Treaties are written agreements through which States voluntarily accept legal obligations. Customary international law develops from a consistent practice of States followed because they believe that such practice is legally required, known as opinio juris. General principles of law, such as good faith and fairness, may help courts where treaties or customary rules do not provide a clear answer.

In the North Sea Continental Shelf Cases (1969), the ICJ explained that State practice and opinio juris are important for establishing customary international law. In the Nicaragua v United States (1986) case, the ICJ recognised that customary international law may exist independently of treaty rules. Similarly, in the Lotus Case (1927), the Permanent Court of International Justice examined State practice while determining the existence of an international legal restriction.

Questions

Question 1

Countries Arvania and Beloria sign a treaty stating that neither country will impose more than a 5% customs duty on agricultural products imported from the other. Two years later, Arvania imposes a 20% duty, arguing that it is free to determine its domestic trade policy. Beloria challenges the decision.

Which of the following is the most appropriate conclusion?

A. Arvania may ignore the treaty because domestic economic policy always prevails over international law.
B. Arvania is bound by the treaty because treaties create legal obligations between States that have accepted them.
C. The treaty is irrelevant unless all countries in the world follow the same rule.
D. Arvania is bound only if the rule has independently become customary international law.

Question 2

For several decades, coastal States have consistently allowed foreign vessels in distress to enter their ports without prior permission. Most States publicly state that international law requires them to provide such assistance. Country Zora suddenly refuses entry to a foreign vessel facing a serious emergency and argues that no written treaty requires it to admit the vessel.

Which principle is most relevant?

A. The consistent practice accompanied by a belief that the practice is legally required may create customary international law.
B. State practice can never create international law unless incorporated into a treaty.
C. Only decisions of the ICJ can create binding rules of international law.
D. International customs apply only when every State has expressly signed a document accepting them.

Question 3

Countries Mira and Taron are involved in an international dispute concerning compensation for damage caused by a cross-border industrial accident. There is no treaty between them dealing specifically with the issue, and no clear customary rule can be established. The international court considers widely recognised principles of fairness, responsibility and good faith found in different legal systems.

What source of international law is the court primarily relying upon?

A. Judicial precedent.
B. International convention.
C. General principles of law recognised by nations.
D. Political declarations made by governments.

Question 4

Country Lumeria argues before an international court that a particular military practice is prohibited under international law. It relies on a treaty containing the prohibition. Country Norvia is not a party to that treaty. However, evidence shows that a large number of States avoid the practice and regard themselves as legally obligated to do so.

Which statement is most accurate?

A. Norvia may still be bound if the prohibition has independently developed into customary international law.
B. Norvia can never be bound because it did not sign the treaty.
C. Every provision contained in a treaty automatically becomes customary international law.
D. Norvia is bound only if the ICJ previously decided a case involving exactly the same countries.

Question 5

An international court is deciding a dispute for which treaty provisions and customary international law provide only limited guidance. The lawyers refer to previous ICJ judgments and scholarly writings of respected international law experts to identify the applicable legal principles.

How should these materials generally be treated?

A. They automatically override treaties and customary international law.
B. They are binding international legislation applicable to every State.
C. They are subsidiary means that may help determine rules of international law.
D. They cannot be considered by international courts under any circumstances.

Answers and Explanations

1. B — Arvania is bound by the treaty because treaties create legal obligations between States that have accepted them.

Treaties are one of the principal sources of international law under Article 38(1) of the ICJ Statute. Once States validly enter into an international agreement, they are generally expected to perform their treaty obligations in good faith. Arvania cannot simply disregard the agreed customs-duty limit merely because the subject also concerns domestic economic policy.

2. A — The consistent practice accompanied by a belief that the practice is legally required may create customary international law.

Customary international law generally requires two elements: sufficiently consistent State practice and opinio juris, meaning a belief among States that the practice is followed because international law requires it. The situation reflects the reasoning discussed in cases such as the North Sea Continental Shelf Cases. A written treaty is therefore not always necessary for an international legal rule to exist.

3. C — General principles of law recognised by nations.

Where neither treaties nor customary international law provide a clear answer, international courts may rely on general principles of law recognised across legal systems. Principles such as good faith, fairness and responsibility may assist the court in resolving gaps in international law.

4. A — Norvia may still be bound if the prohibition has independently developed into customary international law.

A treaty rule and a customary international law rule can exist independently. As recognised by the ICJ in Nicaragua v United States, a principle contained in a treaty may also operate separately as customary international law. Therefore, even though Norvia is not a party to the treaty, it could be bound if sufficient State practice and opinio juris establish the rule as customary law.

5. C — They are subsidiary means that may help determine rules of international law.

Judicial decisions and writings of highly qualified jurists are recognised under Article 38(1) of the ICJ Statute as subsidiary means for determining rules of law. They help courts understand and identify international legal principles, but they do not ordinarily have the same status as treaties, customary international law or general principles of law.