CSS International Law chapter 1: Nature and sources MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

48 exam-style questions on Nature and sources, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

48 questions · 3 topics · 10 per test

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What chapter 1 covers

Ten Nature and sources questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. Public international law mainly regulates

  1. A
    the rights and duties of states and other international persons
  2. B
    disputes between citizens that have a foreign element
  3. C
    the internal organisation of each state's own courts
  4. D
    business contracts made between private firms of different countries
Show answer

Answer: A. Public international law governs the relations of states, international organisations and other international persons. Disputes between private parties with a foreign element belong to private international law.

2. Who coined the term 'international law' in 1789?

  1. A
    Emer de Vattel
  2. B
    Jeremy Bentham
  3. C
    Lassa Oppenheim
  4. D
    Hugo Grotius
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Answer: B. Bentham used 'international law' in his Introduction to the Principles of Morals and Legislation (1789) in place of the older 'law of nations'. Grotius and Vattel wrote earlier, and Oppenheim wrote in the twentieth century.

3. Which of the following is NOT one of the sources listed in Article 38(1) of the ICJ Statute?

  1. A
    International conventions
  2. B
    General principles of law recognised by civilised nations
  3. C
    International custom as evidence of a general practice accepted as law
  4. D
    Resolutions of the General Assembly
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Answer: D. General Assembly resolutions are not listed, although they may be evidence of custom. The other three are the primary sources named in paragraph 1(a) to (c).

4. In a monist state where treaties have primacy, a self-executing treaty provision that conflicts with an earlier statute

  1. A
    applies only to foreigners
  2. B
    prevails over the statute
  3. C
    is suspended until the legislature votes
  4. D
    is void
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Answer: B. Where primacy is given to treaties, courts apply the treaty and set aside the conflicting domestic rule.

5. Which fact is hardest for a pure consent theory of international law to explain?

  1. A
    States conclude treaties only when they freely choose to do so
  2. B
    Reservations may be entered where the treaty itself permits them
  3. C
    A new state is bound by customary rules that existed before it came into being
  4. D
    A state may withdraw from a treaty that itself allows withdrawal when its constitution permits it
Show answer

Answer: C. A new state never consented to older custom, yet it is bound by it; this suggests that not all obligation rests on individual consent. The other three examples are fully consistent with consent.

6. The US Constitution (Article VI) says that treaties made under the authority of the United States are

  1. A
    part of the supreme law of the land
  2. B
    advisory unless approved by the Supreme Court
  3. C
    valid only after each state legislature re-enacts them
  4. D
    binding on the President but not on the courts
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Answer: A. The Supremacy Clause makes treaties, with the Constitution and federal statutes, the supreme law of the land; self-executing treaties can be applied by courts directly.

7. Blackstone wrote that the law of nations is 'adopted in its full extent by the common law' and is part of the law of the land. This expresses the doctrine of

  1. A
    persistent objection
  2. B
    incorporation
  3. C
    transformation
  4. D
    recognition
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Answer: B. Blackstone's statement is the classic English expression of incorporation of customary international law into domestic law.

8. States regularly fire ceremonial salutes when a foreign warship visits their port, but they do not regard it as a legal duty. This practice is not custom because it lacks

  1. A
    opinio juris
  2. B
    the consent of the Security Council
  3. C
    a written text
  4. D
    state practice
Show answer

Answer: A. Practice done from courtesy (comity) without a sense of legal obligation does not create custom. The practice itself is regular, so the element missing is opinio juris.

9. Which of these is a 'publicist' in the sense of Article 38(1)(d)?

  1. A
    A newspaper reporter covering a trial
  2. B
    A leading scholar of international law
  3. C
    A diplomat presenting credentials to a head of state
  4. D
    A government press officer
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Answer: B. Publicists are jurists whose writings on international law are evidence of what the law is.

10. Colombia claimed a regional custom of diplomatic asylum in Latin America (Asylum case, 1950). The ICJ rejected the claim because

  1. A
    the practice was uncertain and contradictory, not constant and uniform
  2. B
    Colombia was not a member of the United Nations at that time
  3. C
    customs require ratification by every state in the region
  4. D
    regional customs cannot exist at all in international law, only universal ones
Show answer

Answer: A. The Court accepted that regional custom is possible but held that the practice relied on was too inconsistent to prove a constant and uniform usage.

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Nature and sources: questions students ask

How many Nature and sources MCQs are there?

48, each with the answer and a short explanation, across 3 topics: Nature, basis and history of international law, Sources: Article 38 of the ICJ Statute, International law and municipal law. Every chapter test draws ten of them, so you can take it many times.

Is the CSS International Law chapter 1 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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