PUBLIC INTERNATIONAL LAW UNIT I
- www.lawtool.net
- Aug 16, 2020
- 6 min read
Updated: Apr 24
International law shapes how states, organizations, and individuals interact on the global stage. It consists of rules that are accepted worldwide to govern behavior in international affairs. This post explores the origins, developments, definitions, and sources of international law, as well as its relationship with national laws. Understanding these elements can clarify why international law is crucial in our interconnected world.
PUBLIC INTERNATIONAL LAW UNIT I
Origin, Development and Definition of International Law
Nature and Basis of International Law
Sources of International Law
Relationship between Municipal Law and International Law (Monism, Dualism, British, American and Indian Practice)
Subjects of international law
Historical Roots of International Law
International law dates back to ancient civilizations. Early forms included treaties and agreements among states, such as the peace treaties between the Hittites and Egyptians around 1269 BC. However, modern international law took shape in the 16th and 17th centuries, particularly through the work of Hugo Grotius. His pivotal book, De Jure Belli ac Pacis, argued for common legal standards among nations.
The Treaty of Westphalia in 1648 was another significant milestone. It established the idea of state sovereignty, indicating that each state is governed by its own laws without interference. This marked a shift toward a system where states were seen as equals. The 19th century saw further developments, particularly the codification of international laws governing warfare and diplomacy, propelled by Enlightenment values around human rights.
The establishment of the United Nations (UN) in 1945 after World War II marked a monumental moment for international law. The UN aimed to foster global peace and cooperation, leading to contemporary developments in international legal frameworks that address issues like climate change and terrorism.
Origin, Development and Definition of International Law
Origin and Development:
Ancient Times: Ideas of international law existed in ancient civilizations like India (Manu), Greece, and Rome, with concepts of treaties, envoys, and war conduct.
Medieval Period: The Catholic Church and feudal system influenced early international norms.
Modern Era (17th Century): Hugo Grotius, known as the “Father of International Law,” laid its foundation with De Jure Belli ac Pacis (1625).
Post-WWII Development: Establishment of the United Nations (1945) led to codification and institutional development.
Definition:
Understanding International Law's Nature
Unlike domestic law, which operates within a specific jurisdiction and is enforced by national authorities, international law functions on the consent of states. Its decentralized nature means there is often no central authority to enforce compliance.
Key principles of international law include:
Respect for Sovereignty: States have equal rights and responsibilities.
Treaty Obligations: Countries are expected to follow international agreements they sign.
Human Rights Promotion: There is a global commitment to protect the rights of individuals, influenced by various international treaties and norms.
Because international law relies on voluntary adherence, its effectiveness depends largely on the willingness of states to fulfill their commitments. This structure is one of the defining characteristics that distinguishes international law from domestic legal systems.
Nature and Basis of International Law
Nature:
Legal vs. Moral Debate: Critics argue it lacks a centralized enforcement mechanism; however, it is legally binding due to state consent.
Horizontal Structure: Unlike domestic law, all states are equal (no superior legislature or judiciary).
Basis:
Consent of States: Customary practices and treaties are accepted voluntarily.
Natural Law Theory: Law exists inherently and universally (Grotius).
Positivism: Based on actual consent via treaties/customs.
Sociological & Functional Need: Necessary for global cooperation (trade, environment, human rights)
Sources of International Law
International law derives from four key sources:
Treaties: These are formal agreements between states that create binding obligations. The Vienna Convention on the Law of Treaties (1969) outlines how treaties are created, interpreted, and enforced. An example is the Paris Agreement, where nearly 200 countries committed to combatting climate change.
Customary International Law: This arises from generally accepted practices and norms that states follow from a sense of legal obligation, known as opinio juris. Notable examples include the principle of diplomatic immunity and the prohibition against genocide, which have been recognized over time as binding norms.
General Principles of Law: These include established principles recognized by civilized nations, such as fairness and justice, which apply where no treaty or customary law exists.
Judicial Decisions and Teachings: The rulings from international courts, such as the International Court of Justice, along with scholarly writings, shape the interpretation and understanding of international law. A recent case involving Myanmar highlighted the role of international courts in addressing genocide.
Sources of International Law
Outlined in Article 38(1) of the Statute of the International Court of Justice (ICJ):
International Conventions (Treaties): Written agreements between states.
International Custom: Consistent state practice accepted as law (opinio juris).
General Principles of Law: Recognized by civilized nations (e.g., pacta sunt servanda – agreements must be kept).
Judicial Decisions and Teachings: Subsidiary means (not binding precedent).
Interplay Between International and National Law
The interplay between international law and municipal law can be understood through two main theories: monism and dualism.
Monism
Monism views international and municipal law as an integrated system. In this model, international law automatically becomes part of domestic law, facilitating easier implementation. Countries like the Netherlands and Germany often operate under this framework, enabling swift enforcement of international norms.
Dualism
In contrast, dualism treats international law and national law as separate. Countries, such as the United Kingdom and the United States, typically require that international law be specifically enacted domestically through legislation. For example, in the UK, Parliament can choose to incorporate international treaties into domestic law, while in the US, the Constitution mandates Senate ratification for treaties to take effect.
India employs a mixed approach, recognizing international law's importance in Article 51(c) of its Constitution, which encourages respect for international norms, while still requiring national legislation for implementation.
Relationship between Municipal Law and International Law
Theories:
Monism:
International and municipal law are part of a single legal system.
International law automatically becomes part of domestic law.
Example: Netherlands.
Dualism:
International law and municipal law are separate.
Treaties/customary laws need transformation before enforcement domestically.
Example: Germany.
National Practices:
British Practice:
Follows dualism. Treaties need an Act of Parliament to be enforceable.
American Practice:
Mixed approach. Self-executing treaties apply directly; non-self-executing ones need Congressional action.
Indian Practice:
Follows dualism. Under Article 253 of the Constitution, Parliament can legislate to implement treaties.
Courts interpret municipal law in harmony with international law, if not contradictory
Who Are the Subjects of International Law?
The term "subjects" in international law refers to entities that have rights and obligations. The primary subjects include:
States: Sovereign countries are the main subjects, having rights to territorial integrity and self-defense. For instance, in 2022, countries asserted their sovereignty during territorial disputes, illustrating the practical application of such rights.
International Organizations: Organizations like the United Nations and the World Trade Organization can create binding obligations through treaties and have specific rights under international law.
Non-Governmental Organizations (NGOs): NGOs play a crucial role in promoting human rights and humanitarian efforts. They have influenced international norms, notably in human rights advocacy, such as the work of Amnesty International.
Individuals: Individuals are increasingly recognized as subjects, especially in human rights law and international criminal law. The International Criminal Court holds individuals accountable for crimes like genocide and war crimes, reflecting a growing accountability trend.
Corporations: Transnational corporations now have significant impacts on international law, particularly in trade and environmental standards. Their operations can influence regulatory frameworks and contribute to global governance issues.
Subjects of International Law
Traditional View:
Only sovereign states were subjects.
Modern View:
Now includes:
States: Primary subjects with full legal personality.
International Organizations: e.g., UN, WHO – have rights and duties.
Individuals: After WWII (Nuremberg Trials), individuals can be held liable (e.g., human rights, war crimes).
Non-State Actors: Corporations, NGOs, rebel groups (limited capacity).
Multinational Corporations: Recognized in investment and trade law.
Final Thoughts
International law is more than a collection of rules; it is a vital framework that regulates interactions among states and other entities globally. Its origins, spanning ancient practices to modern treaties, demonstrate its adaptability to contemporary challenges. The decentralized nature of international law sets it apart from municipal law, yet its principles, such as sovereignty and human rights, remain cornerstones of its authority.
Through its sources—treaties, customary laws, general principles, and judicial decisions—international law continually evolves. The relationship between international and municipal law, explored through monism and dualism, further shapes how states engage with global standards.
Understanding the subjects of international law helps us appreciate the shifting landscape of global accountability. As the world becomes increasingly interconnected, grasping the foundations and dynamics of international law is essential for navigating the complexities of international relations.

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