UCLA-LAW-250 INTERNATIONAL LAW EXAM PREDICTION
2026 Questions and correct answers
1. Which of the following is NOT considered a formal source of
international law under Article 38(1) of the ICJ Statute?
A. International conventions (treaties)
B. International custom as evidence of general practice accepted as
law
C. General principles of law recognized by civilized nations
D. Resolutions of the United Nations General Assembly
Correct Answer: D
Explanation: Article 38(1) of the ICJ Statute lists treaties, custom,
and general principles as formal sources. UN General Assembly
resolutions are generally considered soft law or subsidiary means,
not formal binding sources, though they may reflect customary law.
2. A state may reserve to a treaty provision unless:
A. The reservation is made at the time of signature
B. The reservation is expressly prohibited by the treaty
C. The reservation is communicated in writing
D. The reserving state is a sovereign nation
Correct Answer: B
Explanation: Under the Vienna Convention on the Law of Treaties
(Article 19), reservations are prohibited if the treaty expressly
forbids them, if only specified reservations are allowed and the
reservation is not among them, or if the reservation is incompatible
with the treaty's object and purpose.
3. Which principle prohibits states from intervening in the internal
affairs of another state?
, A. Pacta sunt servanda
B. Non-intervention
C. Jus cogens
D. Lex posterior derogat legi priori
Correct Answer: B
Explanation: The principle of non-intervention is a cornerstone of
international law, prohibiting states from interfering in matters
within the domestic jurisdiction of another state. Pacta sunt
servanda refers to treaty compliance, jus cogens to peremptory
norms, and lex posterior to later laws overriding earlier ones.
4. The concept of "jus cogens" refers to:
A. Treaty obligations that can be terminated unilaterally
B. Peremptory norms of international law from which no derogation
is permitted
C. Customary international law that applies only to developed states
D. Soft law instruments with no binding force
Correct Answer: B
Explanation: Jus cogens (peremptory norms) are fundamental
principles of international law from which no derogation is
permitted, such as prohibitions against genocide, slavery, torture,
and aggression. Examples include the prohibition of genocide and
crimes against humanity.
5. Which case established the "effective control" test for attributing
conduct of non-state actors to a state?
A. Nicaragua v. United States (1986)
B. Bosnia v. Serbia (2007)
C. Arrest Warrant case (2002)
D. Gabčíkovo-Nagymaros case (1997)
Correct Answer: A
Explanation: In Nicaragua v. United States (1986), the ICJ
established that a state is responsible for acts of non-state actors
only if it exercised "effective control" over specific operations. The
, Bosnia v. Serbia case later refined this to "overall control" for
certain contexts.
6. Under the UN Charter, when is the use of force by a state permissible
without Security Council authorization?
A. For humanitarian intervention without Security Council approval
B. In self-defense against an armed attack under Article 51
C. To protect nationals abroad without imminent threat
D. For regime change to promote democracy
Correct Answer: B
Explanation: Article 51 of the UN Charter permits self-defense
against an armed attack until the Security Council takes measures.
Humanitarian intervention without Security Council approval,
protecting nationals without imminent threat, and regime change
are generally not considered lawful under contemporary
international law.
7. The doctrine of "sovereign immunity" bars:
A. All lawsuits against foreign states in domestic courts
B. Commercial activities of foreign states from suit
C. Jurisdiction of domestic courts over foreign states for sovereign
acts (jure imperii)
D. Criminal prosecution of foreign heads of state only
Correct Answer: C
Explanation: Sovereign immunity protects foreign states from
jurisdiction in domestic courts for sovereign acts (jure imperii) but
not necessarily for commercial acts (jure gestionis) under the
restrictive theory of immunity adopted by many states.
8. Which of the following best describes "opinio juris" in the formation
of customary international law?
, A. The physical practice of states
B. The belief that state practice is legally obligatory
C. The written agreement between states
D. The decision of an international court
Correct Answer: B
Explanation: Opinio juris is the psychological element of customary
international law—the belief that states follow a practice because
they believe it is legally required, not merely out of convenience or
habit. Both state practice and opinio juris are required for custom.
9. The principle of "pacta sunt servanda" means:
A. Treaties are void if they violate jus cogens
B. Agreements must be kept; treaties are binding and must be
performed in good faith
C. States can withdraw from treaties at any time
D. Treaties supersede customary international law
Correct Answer: B
Explanation: Pacta sunt servanda (Article 26 of the Vienna
Convention) establishes that every treaty in force is binding upon
the parties and must be performed by them in good faith. This is a
fundamental principle of treaty law.
10. Which tribunal was the first permanent international criminal
court?
A. International Military Tribunal (Nuremberg)
B. International Criminal Tribunal for the former Yugoslavia (ICTY)
C. International Criminal Court (ICC)
D. International Court of Justice (ICJ)
Correct Answer: C
Explanation: The International Criminal Court (ICC), established by
the Rome Statute in 2002 and beginning operations in 2002, is the
first permanent international criminal court. Nuremberg and ICTY
were ad hoc tribunals.
2026 Questions and correct answers
1. Which of the following is NOT considered a formal source of
international law under Article 38(1) of the ICJ Statute?
A. International conventions (treaties)
B. International custom as evidence of general practice accepted as
law
C. General principles of law recognized by civilized nations
D. Resolutions of the United Nations General Assembly
Correct Answer: D
Explanation: Article 38(1) of the ICJ Statute lists treaties, custom,
and general principles as formal sources. UN General Assembly
resolutions are generally considered soft law or subsidiary means,
not formal binding sources, though they may reflect customary law.
2. A state may reserve to a treaty provision unless:
A. The reservation is made at the time of signature
B. The reservation is expressly prohibited by the treaty
C. The reservation is communicated in writing
D. The reserving state is a sovereign nation
Correct Answer: B
Explanation: Under the Vienna Convention on the Law of Treaties
(Article 19), reservations are prohibited if the treaty expressly
forbids them, if only specified reservations are allowed and the
reservation is not among them, or if the reservation is incompatible
with the treaty's object and purpose.
3. Which principle prohibits states from intervening in the internal
affairs of another state?
, A. Pacta sunt servanda
B. Non-intervention
C. Jus cogens
D. Lex posterior derogat legi priori
Correct Answer: B
Explanation: The principle of non-intervention is a cornerstone of
international law, prohibiting states from interfering in matters
within the domestic jurisdiction of another state. Pacta sunt
servanda refers to treaty compliance, jus cogens to peremptory
norms, and lex posterior to later laws overriding earlier ones.
4. The concept of "jus cogens" refers to:
A. Treaty obligations that can be terminated unilaterally
B. Peremptory norms of international law from which no derogation
is permitted
C. Customary international law that applies only to developed states
D. Soft law instruments with no binding force
Correct Answer: B
Explanation: Jus cogens (peremptory norms) are fundamental
principles of international law from which no derogation is
permitted, such as prohibitions against genocide, slavery, torture,
and aggression. Examples include the prohibition of genocide and
crimes against humanity.
5. Which case established the "effective control" test for attributing
conduct of non-state actors to a state?
A. Nicaragua v. United States (1986)
B. Bosnia v. Serbia (2007)
C. Arrest Warrant case (2002)
D. Gabčíkovo-Nagymaros case (1997)
Correct Answer: A
Explanation: In Nicaragua v. United States (1986), the ICJ
established that a state is responsible for acts of non-state actors
only if it exercised "effective control" over specific operations. The
, Bosnia v. Serbia case later refined this to "overall control" for
certain contexts.
6. Under the UN Charter, when is the use of force by a state permissible
without Security Council authorization?
A. For humanitarian intervention without Security Council approval
B. In self-defense against an armed attack under Article 51
C. To protect nationals abroad without imminent threat
D. For regime change to promote democracy
Correct Answer: B
Explanation: Article 51 of the UN Charter permits self-defense
against an armed attack until the Security Council takes measures.
Humanitarian intervention without Security Council approval,
protecting nationals without imminent threat, and regime change
are generally not considered lawful under contemporary
international law.
7. The doctrine of "sovereign immunity" bars:
A. All lawsuits against foreign states in domestic courts
B. Commercial activities of foreign states from suit
C. Jurisdiction of domestic courts over foreign states for sovereign
acts (jure imperii)
D. Criminal prosecution of foreign heads of state only
Correct Answer: C
Explanation: Sovereign immunity protects foreign states from
jurisdiction in domestic courts for sovereign acts (jure imperii) but
not necessarily for commercial acts (jure gestionis) under the
restrictive theory of immunity adopted by many states.
8. Which of the following best describes "opinio juris" in the formation
of customary international law?
, A. The physical practice of states
B. The belief that state practice is legally obligatory
C. The written agreement between states
D. The decision of an international court
Correct Answer: B
Explanation: Opinio juris is the psychological element of customary
international law—the belief that states follow a practice because
they believe it is legally required, not merely out of convenience or
habit. Both state practice and opinio juris are required for custom.
9. The principle of "pacta sunt servanda" means:
A. Treaties are void if they violate jus cogens
B. Agreements must be kept; treaties are binding and must be
performed in good faith
C. States can withdraw from treaties at any time
D. Treaties supersede customary international law
Correct Answer: B
Explanation: Pacta sunt servanda (Article 26 of the Vienna
Convention) establishes that every treaty in force is binding upon
the parties and must be performed by them in good faith. This is a
fundamental principle of treaty law.
10. Which tribunal was the first permanent international criminal
court?
A. International Military Tribunal (Nuremberg)
B. International Criminal Tribunal for the former Yugoslavia (ICTY)
C. International Criminal Court (ICC)
D. International Court of Justice (ICJ)
Correct Answer: C
Explanation: The International Criminal Court (ICC), established by
the Rome Statute in 2002 and beginning operations in 2002, is the
first permanent international criminal court. Nuremberg and ICTY
were ad hoc tribunals.
