Foundations and Theories of Public International Law

Posted on Nov 7, 2025 in Law

History of International Law

Origins of International Law

• International law does not exist in a vacuum – shaped by historical context and key events.

• Early interactions between communities (trade, war) created customary rules.

• Ancient traces: Mesopotamia, Egypt, India, China, Greece.

Foundational Thinkers (15th–17th C.)

• Francisco de Vitoria – Indigenous peoples’ inherent sovereignty and property rights.

• Francisco Suarez – Jus gentium (law of nations); right to rebellion.

• Alberico Gentili – Secularized international law, humane conduct in war (De Jure Belli).

• Hugo Grotius – “Father of IL”, De Jure Belli ac Pacis, natural law, just war, freedom of seas.

The Peace of Westphalia (1648)

• Key outcomes:

  • Sovereign equality – all states equal.

  • Non-interference – no external meddling in domestic affairs.

  • Territorial integrity – borders respected.

• Established the modern state system.

17th–19th Century Theories

• Samuel Pufendorf – Secular natural law applied to states.

• Emer de Vattel – Equality of states in Le Droit des Gens.

• Immanuel Kant – Perpetual Peace, early vision of human rights and international federation.

• Jeremy Bentham – Coined “international law”, utilitarian focus on peace.

19th Century Developments

• Congress of Vienna (1815) – Balance of power.

• Age of Empire – Sovereignty limited to “civilized” European powers.

• Growth of multilateralism and international humanitarian law.

20th Century Milestones

• League of Nations & Permanent Court of International Justice (PCIJ).

• SS Lotus case (1927) – International law based on state consent.

• Positivism dominates: scientific, consent-based, rules between states.

Post-WWII Era

• Creation of **United Nations (UN)**, ICJ, decolonization, rise in number of states (51 in 1945 → 190+ today).

• Human rights norms challenged non-intervention.

Contemporary Challenges

• Globalization: economic, environmental, human rights issues transcend borders.

• International Criminal Court (ICC) – accountability for individuals.

• Regulation of multinational corporations, digital data flows.

Theoretical Perspectives on International Law

Traditional Approaches

Critical Perspectives

1. New Haven School

   • Focus on process, not rules.

   • Law guided by human dignity and liberal democracy.

   • Criticized for being aligned with US policy.

2. Critical Legal Studies (CLS)

   • Law is not neutral, reflects power hierarchies.

   • Indeterminacy: rules interpreted to benefit the powerful.

3. TWAIL (Third World Approaches)

   • International law born in colonialism, perpetuates inequalities.

   • Advocates reform to serve Global South interests.

   • Antony Anghie: sovereignty doctrine forged through colonial encounters.

4. Feminist Approaches

   • IL developed in patriarchal systems, excludes women.

   • Gendered power relations → need for representation and reform.

Additional Perspectives

• Marxist – IL supports global capitalism and imperialism.

• Postcolonial – Critiques Western dominance of legal concepts.

• Global Governance Critique – Highlights democratic deficit and elite control.

Grotian Moment

Periods of profound change in IL:

• Climate crisis.

• COVID-19 governance.

• Cybersecurity and technology.

• Rise of China.

• Challenges to liberal order.

International vs. Domestic Law

The Core Debate: Monism vs. Dualism

How international rules are integrated into domestic systems.

Critiques of Monism and Dualism

• Monism – Democratic deficit, judicial activism, uncertainty.

• Dualism – Excuse for non-compliance, weak individual rights protection.

Hybrid Systems: Blend both, e.g., US (self-executing vs. non-self-executing treaties).

Incorporating International Law

Sources

1. Treaties

   • Self-executing – automatically apply (e.g., human rights treaties in monist states).

   • Non-self-executing – need domestic legislation.

2. Customary International Law

   • Automatically part of domestic law in many countries.

   • Trendtex case: evolving standards like anti-slavery applied directly.

3. Judicial Decisions & Principles

   • ICJ rulings used for persuasive authority.

   • Principles like fairness, good faith fill gaps.

Conflict Resolution

EU Example: EU law takes precedence over national law to ensure uniform application.

Criteria for Statehood

Montevideo Convention (1933) – Four Criteria

1. Permanent Population

2. Defined Territory

3. Government – effective control of territory.

4. Capacity to Enter Relations – independence from other states.

Self-Determination

• UN Charter Art. 1(2) – key in decolonization.

• Limits: must balance with territorial integrity (Quebec case).

• Modern debates: Kosovo, Tibet.

Recognition Theories

Recognition of Governments

• Based on effective control.

• Political tool: e.g., recognition of Guaido in Venezuela.

Subjects of International Law

International Organizations (IOs)

• Created by treaty, legal personality recognized under international law.

Examples: **UN**, WTO, EU, **WHO**, ICAO.

Legal Personality

Ability to:

• Conclude treaties.

• Maintain diplomatic relations.

• Claim reparations (Reparations for Injuries case, ICJ).

Powers

• Express powers – written in founding treaty.

• Implied powers – necessary to fulfill purpose (Certain Expenses case).

Public International Law: Definition and Principles

Definition

• Governs relations between states and international organizations.

• Aims for peace, human rights protection, cooperation, and global problem-solving.

Characteristics

• No global parliament or police.

• Enforcement via:

  • UN peacekeepers.

  • Regional coalitions (e.g., NATO).

Core Principles

• Sovereign equality.

• Non-use of force.

• Respect for independence.