Key International Court of Justice Cases

Why This Matters

The International Court of Justice (ICJ) isn't just a courtroom—it's where the abstract principles of international law become concrete. When you study these cases, you're learning how concepts like state sovereignty, humanitarian obligations, legal personality, and the limits of state action actually get applied when nations clash. Every case here represents a moment when the international community had to decide: What rules bind states? Who can be held accountable? What happens when sovereignty collides with human rights?

You're being tested on more than case names and dates. Exam questions will ask you to identify which legal principles a case established, compare how different cases address similar issues (like state responsibility or use of force), and explain why ICJ rulings matter even when states don't comply. Don't just memorize facts—know what concept each case illustrates and be ready to use these as evidence in FRQs about international law's effectiveness and limitations.

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State Responsibility and Non-Intervention

These foundational cases establish when and how states can be held accountable for their actions—or failures to act. The principle of state responsibility holds that states must answer for internationally wrongful acts, whether through direct action or negligent omission.

Nicaragua v. United States (1986)

• Landmark ruling on non-intervention—the ICJ found the U.S. violated international law by supporting Contra rebels and mining Nicaraguan harbors
• Established limits on self-defense claims—rejected U.S. argument that actions were collective self-defense, setting precedent for when force is legally justified
• U.S. non-compliance became its own lesson—the U.S. withdrew from ICJ jurisdiction and ignored the reparations order, illustrating the court's enforcement limitations

Corfu Channel Case (1949)

• First contentious case in ICJ history—Albania held responsible for British ships damaged by mines in Albanian territorial waters
• Due diligence obligation established—states must warn others of known dangers in their territory, even if they didn't create those dangers
• Innocent passage affirmed—reinforced that warships may transit territorial waters peacefully, a cornerstone of maritime law

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Legal Personality and International Organizations

These cases define who counts as a "person" under international law—not just states, but organizations that can hold rights and bring claims.

Reparation for Injuries (1949)

• Established UN legal personality—the ICJ ruled the UN can bring claims against states for harm to its agents, even against non-member states
• Created the concept of "functional personality"—international organizations have legal capacity to the extent needed to fulfill their purposes
• Practical protection for international workers—enabled the UN to seek compensation after Count Bernadotte's assassination in Palestine

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Humanitarian Law and Mass Atrocities

The ICJ's most difficult cases involve genocide and crimes against humanity. These rulings test how international law addresses the worst human conduct and whether states can be held collectively responsible for atrocities.

Bosnia and Herzegovina v. Serbia and Montenegro (2007)

• First genocide judgment against a state—ICJ found Serbia violated the Genocide Convention by failing to prevent the Srebrenica massacre
• Distinguished state responsibility from individual guilt—Serbia wasn't found to have committed genocide, but failed its duty to prevent it
• High evidentiary bar demonstrated—court required proof of specific intent (dolus specialis), showing how difficult genocide claims are to prove

Croatia v. Serbia (2015)

• Mutual genocide allegations rejected—ICJ found atrocities occurred on both sides but neither state proved the other committed genocide
• Intent requirement emphasized—acts that could constitute genocide weren't proven to have the specific intent to destroy a group
• Illustrated limitations of ICJ jurisdiction—some claims dismissed for occurring before relevant treaties applied to the parties

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Use of Force and Weapons

These cases address the most consequential question in international law: When can states use deadly force, and what weapons are permissible?

Legality of Nuclear Weapons (1996)

• Advisory opinion with a famous non-answer—ICJ couldn't definitively rule whether nuclear weapons use would always be illegal
• Humanitarian law principles affirmed—use must distinguish civilians from combatants and avoid unnecessary suffering, standards nuclear weapons struggle to meet
• "Extreme circumstance of self-defense" loophole—court couldn't conclude that nuclear use would be unlawful when a state's survival is at stake

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Environmental Protection and Treaty Compliance

Modern ICJ cases increasingly address environmental obligations and whether states are honoring their treaty commitments.

Gabčíkovo-Nagymaros Project (1997)

• Environmental law meets treaty law—Hungary couldn't unilaterally abandon a dam project with Slovakia, but both had environmental obligations
• Sustainable development recognized—ICJ acknowledged that environmental protection must be balanced with economic development, a principle now central to international environmental law
• Ongoing cooperation required—court ordered both states to negotiate in good faith, emphasizing that shared resources demand shared solutions

Whaling in the Antarctic (2014)

• Treaty interpretation case—ICJ ruled Japan's "scientific whaling" program violated the International Convention for the Regulation of Whaling
• Objective standards applied—court looked at program design, not just Japan's stated intentions, to determine if whaling was genuinely scientific
• Compliance ordered and achieved—Japan actually modified its whaling program after this ruling, a rare example of ICJ effectiveness

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Territorial Disputes and Self-Determination

These cases address how borders are drawn and whether peoples can create new states—questions that pit sovereignty against self-determination.

Kosovo Advisory Opinion (2010)

• Declaration of independence wasn't illegal—ICJ found Kosovo's 2008 declaration didn't violate international law, but didn't say Kosovo was legally a state
• Narrow ruling, broad implications—court avoided ruling on whether Kosovo had a right to independence, only that declaring it wasn't prohibited
• Self-determination debate continues—opinion didn't resolve when secession is legitimate, leaving the question open for future disputes

Maritime Delimitation: Somalia v. Kenya (2021)

• Equidistance method applied—ICJ drew the maritime boundary using geometric principles rather than Kenya's preferred parallel line
• Resource implications significant—the ruling affected access to potentially oil-rich waters in the Indian Ocean
• Kenya's non-compliance problematic—Kenya rejected the ruling, echoing the enforcement challenges seen in Nicaragua and raising questions about ICJ authority

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Quick Reference Table

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Self-Check Questions

1. Which two cases both address state responsibility but differ in whether the state's wrongdoing was active or passive? What legal principle does each illustrate?

2. If an FRQ asks you to evaluate whether the ICJ can effectively enforce international law, which cases would you use as evidence for and against its effectiveness?

3. Compare Bosnia v. Serbia and Croatia v. Serbia: Why did one succeed in proving a Genocide Convention violation while the other failed?

4. How does the Reparation for Injuries case change who can participate in the international legal system? Why does this matter for understanding international organizations?

5. A question asks about international environmental law's development. Which two cases would you cite, and what different aspects of environmental obligations does each address?