UN peacekeeping developed through practice rather than an express Charter provision. Its legal framework draws on Security Council mandates, consent, impartiality, rules on the use of force, status of forces agreements, international humanitarian law, human rights, and the rules governing attribution and responsibility.

International environmental law governs environmental protection, transboundary harm, shared resources, and global environmental risks through treaties, customary international law, and general international law. This article explains prevention, precaution, environmental impact assessment, sustainable development, major treaty regimes, compliance, and State responsibility.

Extradition allows one State to surrender an accused or convicted person to another for prosecution or punishment. Its legality depends on treaties, domestic law, refusal grounds, human rights obligations, and, in some cases, duties to extradite or prosecute.

Diplomatic protection allows a State to invoke another State’s international responsibility for injury suffered by a protected national or legal person. Its operation depends on nationality of claims, exhaustion of local remedies, corporate protection rules, and the relationship between general international law and direct treaty-based remedies.

State succession raises difficult questions about what happens when one State replaces another in responsibility for a territory. This article examines continuity, treaty obligations, property, State debts, nationality, organizational membership, and State responsibility under international law.

State recognition in international law determines how States accept and legally treat contested claims to statehood. This article examines the criteria of statehood, recognition theories, legal effects, non-recognition, withdrawal, UN membership, and cases including Kosovo, Palestine, Taiwan, and Northern Cyprus.

International Criminal Law governs individual criminal responsibility for crimes under international law. This article explains its sources, historical development, core crimes, modes of liability, ICC jurisdiction, immunities, national prosecutions, and the limits of international criminal justice.

The Principle of Non-Intervention in International Law protects States against coercive interference in matters they are legally entitled to decide freely. This article examines its customary basis, the coercion test, leading ICJ cases, economic pressure, elections, and cyber operations.