Public International Law governs relationships between sovereign states, international organizations, and other entities on matters of international concern. It includes rules, norms, and principles regulating global issues like sovereignty, human rights, and environmental protection.

1. Definition and Nature of Public International Law

• Definition: A body of rules binding states and other entities in international interactions.
• Subjects: States, international organizations, individuals (in limited contexts like human rights and war crimes).
• Sources:
  • Primary:
    1. International Treaties (Conventions): Agreements between states, e.g., UN Charter.
    2. Customary International Law: Practices accepted as law, e.g., immunity of diplomats.
    3. General Principles of Law: Recognized by civilized nations, e.g., good faith.
  • Subsidiary:
    1. Judicial decisions (e.g., ICJ rulings).
    2. Scholarly writings (jurists).

2. Principles of International Law

1. Sovereign Equality of States:
   • All states, regardless of size or power, are equal under international law.
2. Non-Intervention:
   • No state may interfere in the internal affairs of another state.
3. Peaceful Settlement of Disputes:
   • Conflicts must be resolved through negotiation, mediation, arbitration, or adjudication.
4. Prohibition of the Use of Force:
   • Except in self-defense or with UN Security Council authorization (Article 2(4), UN Charter).
5. Right to Self-Determination:
   • People have the right to freely determine their political status.
6. Pacta Sunt Servanda:
   • Agreements must be honored in good faith.

3. Subjects of Public International Law
4. States

• Criteria for Statehood (Montevideo Convention, 1933):
  1. Permanent population.
  2. Defined territory.
  3. Government.
  4. Capacity to enter into relations with other states.

1. International Organizations

• Created by states through treaties to address specific issues, e.g.,United Nations, World Health Organization.

1. Individuals

• Gaining recognition through human rights, war crimes tribunals, and treaties (e.g., ICC prosecutes individuals for genocide).

1. Non-State Actors

• Multinational corporations, NGOs, and insurgent groups.

4. Sources of International Law
5. Treaties

• Types:
  • Bilateral (between two states).
  • Multilateral (involving multiple states, e.g., Paris Climate Agreement).
• Binding Nature:
  • Treaties are binding on parties unless terminated by mutual consent or a material breach.

1. Customary Law

• Requires:
  1. General and consistent state practice.
  2. Belief that such practice is legally obligatory (opinio juris).

1. Judicial Decisions

• International Court of Justice (ICJ), International Criminal Court (ICC), and arbitral tribunals contribute to legal interpretation.

1. Soft Law

• Non-binding resolutions and declarations that influence state behavior, e.g., Universal Declaration of Human Rights (1948).

5. The United Nations and International Law
6. UN Charter:

• Foundation of modern international law.
• Key Principles:
  1. Maintenance of international peace and security.
  2. Respect for human rights.
  3. Promotion of social progress.

1. Key Organs and Their Roles:

1. General Assembly:
   • Discusses and recommends measures.
2. Security Council:
   • Maintains peace, authorizes military action.
3. International Court of Justice (ICJ):
   • Resolves disputes between states.

6. International Humanitarian Law (IHL)
7. Definition:

• Laws regulating armed conflicts to protect those not participating in hostilities.

1. Key Treaties:

1. Geneva Conventions (1949):
   • Protection of wounded soldiers, prisoners of war, and civilians.
2. Hague Conventions:
   • Rules of warfare and treatment of combatants.

7. International Criminal Law
8. Key Principles:

• Individuals can be held accountable for international crimes:
  1. Genocide.
  2. War Crimes.
  3. Crimes Against Humanity.
  4. Aggression.

1. International Criminal Court (ICC):

• Established under the Rome Statute (1998).
• Tries individuals for the most serious crimes.

8. Law of the Sea
9. United Nations Convention on the Law of the Sea (UNCLOS, 1982):

1. Territorial Waters: Sovereign up to 12 nautical miles.
2. Exclusive Economic Zone (EEZ): Rights to resources up to 200 nautical miles.
3. High Seas: Open to all states, beyond national jurisdiction.

9. Human Rights in International Law
10. Universal Declaration of Human Rights (1948):

• Non-binding but influential.

1. Key Treaties:

1. International Covenant on Civil and Political Rights (ICCPR).
2. International Covenant on Economic, Social, and Cultural Rights (ICESCR).

1. Enforcement:

• Monitored by bodies like the UN Human Rights Council.

10. International Environmental Law
11. Key Treaties:

1. Paris Agreement (2015): Climate change mitigation.
2. Convention on Biological Diversity (1992).

1. Principles:

1. Sustainable Development.
2. Precautionary Principle: Prevent environmental harm when in doubt.

11. Diplomatic Immunity
12. Vienna Convention on Diplomatic Relations (1961):

1. Diplomatic Immunity:
   • Protects diplomats from host state jurisdiction.

1. Exceptions:

1. Acts unrelated to official functions.

12. Settlement of Disputes
13. Peaceful Means:

1. Negotiation.
2. Mediation.
3. Arbitration (e.g., Permanent Court of Arbitration).
4. Adjudication (e.g., ICJ).

1. Enforcement Mechanisms:

• UN Security Council enforces ICJ decisions.

13. Landmark Cases in International Law

1. Corfu Channel Case (1949):
   • Duty of states not to allow their territory to be used for harmful acts against other states.
2. Barcelona Traction Case (1970):
   • Recognized state responsibility in protecting foreign investments.
3. Trail Smelter Case (1938–41):
   • Established the principle of state liability for transboundary harm.
4. South China Sea Arbitration (2016):
   • Addressed maritime disputes under UNCLOS.

14. Contemporary Issues

1. Cyber Warfare and International Law:
   • Lack of clear rules governing cyber operations.
2. Climate Change:
   • Legal obligations under the Paris Agreement.
3. Space Law:
   • Governing activities beyond Earth under the Outer Space Treaty (1967).