Leading Cases in International Law: ICJ, PCIJ and India

International law is learned through its cases more than through any code. A handful of decisions of the Permanent Court of International Justice, the International Court of Justice, arbitral tribunals and national courts supply most of the principles examined in judiciary papers. This note collects them by theme, states the principle each stands for in a single line, and cross-refers to the topic where it is discussed in detail. Indian cases are gathered in the final section.

Figure 1: Landmark decisions across a century

1. Sources and Custom

• S.S. Lotus (France v Turkey), PCIJ, 1927. Restrictions on the independence of states cannot be presumed; Turkey could prosecute a French officer for a collision on the high seas causing Turkish deaths (Topic 33)
• Asylum (Colombia v Peru), ICJ, 1950. A party relying on a regional custom must prove a constant and uniform usage accepted as law; diplomatic asylum was not established as a custom (Topic 42)
• Anglo-Norwegian Fisheries (UK v Norway), ICJ, 1951. Norway's straight baselines were valid; a state that has consistently objected to an emerging rule is not bound by it, the persistent objector principle (Topic 8)
• North Sea Continental Shelf, ICJ, 1969. A treaty rule becomes custom only with widespread and representative practice, including of specially affected states, and opinio juris; equidistance was not customary (Topic 8)
• Nicaragua v United States, ICJ, 1986. Custom exists alongside an identical treaty rule; practice need not be perfect, as inconsistent conduct treated as a breach confirms the rule (Topic 8)
• Right of Passage (Portugal v India), ICJ, 1960. A local custom may exist between two states only (Topic 8)

2. Treaties and Unilateral Acts

• Reservations to the Genocide Convention, ICJ, 1951. A reservation is permissible if compatible with the object and purpose of the treaty (Topic 14)
• Temple of Preah Vihear (Cambodia v Thailand), ICJ, 1962. By accepting and benefiting from a map for decades without protest, Thailand was precluded from denying the boundary it showed (Topic 11)
• Fisheries Jurisdiction (UK v Iceland), ICJ, 1973. A fundamental change of circumstances must radically transform the obligations still to be performed (Topic 17)
• Nuclear Tests (Australia and New Zealand v France), ICJ, 1974. Public unilateral declarations made with the intention to be bound create legal obligations (Topic 11)
• Gabčíkovo-Nagymaros (Hungary v Slovakia), ICJ, 1997. Necessity, impossibility and changed circumstances did not justify termination; treaty law and state responsibility are distinct (Topics 17 and 43)
• Kasikili/Sedudu Island (Botswana v Namibia), ICJ, 1999. Articles 31 and 32 of the Vienna Convention reflect customary rules of interpretation (Topic 15)

3. States, Recognition and International Organisations

• Tinoco Arbitration (UK v Costa Rica), 1923. A government in effective control binds the state, even if unrecognised by others (Topic 20)
• Luther v Sagor, English Court of Appeal, 1921. Recognition of a government is retroactive to the date of its establishment (Topic 20)
• Reparation for Injuries, ICJ, 1949. The UN has international personality and may claim reparation, including for injury to its agents (Topic 23)
• Western Sahara, ICJ, 1975. Ties with Morocco and Mauritania did not displace the right of the people to self-determination (Topic 24)
• Kosovo, ICJ, 2010. General international law contains no prohibition of declarations of independence (Topic 24)
• Chagos Archipelago, ICJ, 2019. The decolonisation of Mauritius was not lawfully completed, as the Chagos were detached without the free will of the people; the UK must end its administration as rapidly as possible (Topic 24)

4. Territory and the Sea

• Island of Palmas (Netherlands v US), 1928. Discovery gives only an inchoate title; sovereignty requires continuous and peaceful display of state authority (Topic 25)
• Legal Status of Eastern Greenland (Denmark v Norway), PCIJ, 1933. Little actual exercise of authority suffices for remote, sparsely populated areas; the Ihlen declaration bound Norway (Topics 11 and 25)
• Clipperton Island, 1931. Possession of an uninhabited territory can be complete when the occupying state appears there and takes formal steps (Topic 25)
• Corfu Channel (UK v Albania), ICJ, 1949. Warships enjoy innocent passage through international straits; every state must not knowingly allow its territory to be used for acts contrary to the rights of others (Topics 27 and 43)
• South China Sea (Philippines v China), 2016. Claims to historic rights within the nine-dash line have no legal basis under UNCLOS (Topic 29)

5. Jurisdiction and Immunities

• Attorney-General of Israel v Eichmann, 1961 and 1962. Universal jurisdiction over crimes against humanity; the manner of the accused's abduction did not bar trial (Topic 34)
• United States Diplomatic and Consular Staff in Tehran, ICJ, 1980. Iran was responsible for failing to protect the embassy and for adopting the militants' conduct (Topics 36 and 43)
• R v Bow Street Magistrate, ex parte Pinochet (No 3), House of Lords, 1999. A former head of state has no immunity for torture after the Convention against Torture bound the states concerned (Topic 34)
• Arrest Warrant (DRC v Belgium), ICJ, 2002. A serving foreign minister enjoys full immunity from foreign criminal jurisdiction, even for international crimes (Topic 34)
• Jurisdictional Immunities (Germany v Italy), ICJ, 2012. State immunity applies to acts of armed forces in armed conflict, even serious violations of humanitarian law (Topic 35)
• LaGrand (2001), Avena (2004) and Jadhav (2019), ICJ. Article 36 of the Vienna Convention on Consular Relations confers individual rights; provisional measures are binding; no espionage exception to consular access (Topic 37)

6. Nationality and Diplomatic Protection

• Mavrommatis Palestine Concessions, PCIJ, 1924. By taking up its national's case, a state asserts its own right (Topic 39)
• Nottebohm (Liechtenstein v Guatemala), ICJ, 1955. Nationality opposable to another state requires a genuine link (Topic 38)
• Barcelona Traction, ICJ, 1970. Only the state of incorporation may protect a company; obligations erga omnes are owed to the international community as a whole (Topics 10 and 39)
• Ahmadou Sadio Diallo (Guinea v DRC), ICJ, 2010. Diplomatic protection extends to violations of the human rights of nationals, and compensation was later awarded in 2012 (Topic 39)

7. State Responsibility

• Factory at Chorzów, PCIJ, 1927 and 1928. Every breach involves an obligation to make reparation, which must wipe out all the consequences of the illegal act (Topic 43)
• Trail Smelter (US v Canada), 1938 and 1941. No state may use its territory to cause serious transboundary harm (Topic 47)
• Rainbow Warrior (New Zealand v France), 1990. France breached its obligations by removing its agents from the island and failing to return them, and a declaration of the breach was appropriate satisfaction (Topic 43)
• Bosnian Genocide (Bosnia v Serbia), ICJ, 2007. Attribution of private conduct requires effective control; Serbia was responsible for failing to prevent the Srebrenica genocide (Topic 43)

8. Use of Force

• Caroline incident, 1837. Anticipatory self-defence requires a necessity that is instant, overwhelming, leaving no choice of means and no moment for deliberation (Topic 50)
• Nicaragua v United States, ICJ, 1986. Only the gravest uses of force are armed attacks; collective self-defence needs a request by the victim (Topic 50)
• Legality of Nuclear Weapons, ICJ, 1996. Use would generally violate humanitarian law; no definitive answer for extreme self-defence (Topics 53 and 55)
• Wall, ICJ, 2004. Article 51 concerns attacks by states; Israel could not invoke it against threats from occupied territory (Topic 50)
• Armed Activities (DRC v Uganda), ICJ, 2005. Uganda's occupation and support to rebels violated the prohibition of force; reparations were fixed in 2022 (Topic 50)

9. Environment and Shared Resources

• Gabčíkovo-Nagymaros, ICJ, 1997. Recognised the concept of sustainable development (Topic 47)
• Pulp Mills (Argentina v Uruguay), ICJ, 2010. Environmental impact assessment is required by general international law for activities with a risk of significant transboundary harm (Topic 47)
• Indus Waters Kishenganga (Pakistan v India), 2013. India could divert waters for the project, but had to maintain a minimum flow (Topic 26)
• Obligations of States in respect of Climate Change, ICJ, 2025. Unanimously, states have binding obligations under treaties and custom to protect the climate system (Topic 47)

10. India

Figure 2: Leading cases involving India

• Jolly George Varghese v Bank of Cochin, 1980. Article 11 of the ICCPR yields to the express provisions of the Code of Civil Procedure, though statutes are read in harmony with it where possible (Topic 5)
• Kesavananda Bharati v State of Kerala, 1973. Article 51 was relied on to prefer a construction of the Constitution consistent with international obligations (Topic 5)
• Kulbhushan Jadhav (India v Pakistan), ICJ, 2019. Pakistan breached Article 36 of the Vienna Convention on Consular Relations and must provide effective review and reconsideration (Topic 37)

11. Frequently Asked Questions

Which case established the principle of genuine link?

Nottebohm (Liechtenstein v Guatemala), decided by the ICJ in 1955. It held that Liechtenstein could not protect Nottebohm against Guatemala because his naturalisation lacked a genuine connection with Liechtenstein.

Which international case did India win on the basis of local custom?

None outright. In Right of Passage (1960), the ICJ found that a local custom gave Portugal a right of passage for private persons, civil officials and goods, but not for armed forces, and that India had not acted contrary to its obligations in refusing passage in 1954.

What is the significance of the Lotus case today?

It is cited for the idea that whatever is not prohibited is permitted to states, though this presumption has been widely criticised. Its specific rule on collisions was reversed by treaty, and Article 97 of UNCLOS now gives penal jurisdiction to the flag state or the state of nationality of the accused.

12. Related Topics

• Topic 7: Sources of International Law. Judicial decisions as a subsidiary means.
• Topic 49: International Court of Justice. Jurisdiction and India's cases.
• Topic 60: International Law Revision Chart. Articles, numbers and dates at a glance.