Is International Law Really Law?

The legal character of international law has been debated for centuries. Unlike domestic legal systems, international law does not operate under a single sovereign authority, universal legislature or centralised enforcement mechanism. This difference led several jurists, particularly early positivists, to question whether international law can properly be called “law”.

The debate essentially concerns one question: If there is no supreme authority above States to make and enforce international law, why should international law be regarded as legally binding?

Modern international legal theory generally accepts international law as a genuine legal system, although its structure and enforcement mechanisms differ significantly from those of domestic law.

Meaning of the Debate

The question “Is International Law Really Law?” concerns the legal validity and binding character of international law.

The debate does not primarily ask whether States follow international law. Rather, it asks whether international rules possess the essential characteristics of law.

The debate became particularly significant because international law lacks some institutions commonly associated with domestic legal systems, such as:

• a universal legislature;
• a central executive authority;
• compulsory jurisdiction of a single international court over all disputes;
• a universally effective enforcement mechanism.

These differences have been used both to challenge and to defend the legal character of international law.

Arguments Against International Law Being “True Law”

Several jurists have argued that international law does not satisfy the requirements of law in the strict sense.

Austin’s Command Theory

The strongest classical criticism is associated with John Austin.

Austin’s command theory defines law as the command of a sovereign, backed by sanctions.

According to this approach, a legal system requires:

1. a determinate sovereign;
2. commands issued by that sovereign;
3. subjects who are legally subordinate to the sovereign;
4. sanctions for disobedience.

International society does not have a single sovereign standing above States.

States are legally sovereign and are not generally subordinate to a superior international government.

Therefore, from Austin’s perspective, international law could not qualify as positive law in the same sense as domestic law.

He regarded international law as positive morality rather than positive law.

Absence of a World Legislature

There is no universal international Parliament with general authority to enact laws binding upon every State.

Treaties generally depend upon participation by States, while customary international law develops through State practice and opinio juris.

This decentralised law-making process has been presented as an argument against treating international law as a conventional legal system.

Absence of Centralised Enforcement

Domestic law is generally backed by State institutions such as police, courts and correctional authorities.

International law lacks a comparable universal enforcement authority.

A State that violates international law may not necessarily face immediate or automatic punishment.

This has led some scholars to argue that international law lacks one of the essential characteristics of law: effective coercive enforcement.

Lack of Universal Compulsory Jurisdiction

International courts do not generally possess unlimited jurisdiction over every State and every dispute.

For example, the jurisdiction of the International Court of Justice in contentious cases depends upon applicable jurisdictional bases.

The absence of universal compulsory jurisdiction has historically been considered another weakness of the international legal system.

Arguments Supporting International Law as Law

The criticism that international law is not “real law” has been strongly challenged by modern legal scholars.

International Law Creates Legal Obligations

International law creates obligations that States generally regard as legally binding.

Treaties establish binding obligations between their parties.

Customary international law also creates legal obligations where the requirements for custom are satisfied.

The legal character of an obligation does not necessarily depend upon the existence of a central police authority.

States Regularly Follow International Law

States routinely conduct their international relations on the assumption that international legal rules exist.

They:

• negotiate treaties;
• invoke international law in diplomatic disputes;
• bring disputes before international courts;
• rely upon customary international law;
• protest violations;
• justify their conduct using legal arguments;
• provide legal explanations for international actions.

This widespread reliance upon legal rules demonstrates that international law is treated as law by its principal actors.

Sanctions Exist, Though They Are Decentralised

The absence of a universal enforcement authority does not mean that international law has no consequences for violations.

International law provides various consequences and mechanisms, including:

• State responsibility;
• diplomatic protests;
• countermeasures where legally permissible;
• reparations;
• economic and political consequences;
• international adjudication;
• collective measures under applicable international instruments.

Enforcement is therefore decentralised rather than completely absent.

International Courts Apply International Law

International courts and tribunals apply international legal rules to disputes.

The International Court of Justice, for example, determines disputes according to international law where it has jurisdiction.

Other international tribunals operate within specialised areas of international law.

The existence of institutions applying international legal rules demonstrates that international law has developed mechanisms for interpretation and adjudication.

H.L.A. Hart’s Approach

H.L.A. Hart provided an influential response to the traditional positivist criticism.

Hart accepted that international law differs from a mature domestic legal system, but he did not conclude that it is therefore not law.

He viewed international law as a system consisting primarily of primary rules, which impose obligations on States.

However, he argued that international law lacked some of the developed secondary rules found in domestic legal systems.

These secondary rules concern matters such as:

• identification of valid rules;
• amendment of rules;
• adjudication;
• enforcement.

Hart therefore treated international law as a less institutionally developed legal system rather than simply denying its legal character.

Primary and Secondary Rules

Hart’s distinction helps explain the structure of international law.

Primary Rules

Primary rules impose substantive obligations.

Examples include rules concerning:

• treaties;
• diplomatic relations;
• prohibition of certain uses of force;
• treatment of individuals;
• State responsibility.

Secondary Rules

Secondary rules concern how primary rules are identified, changed and applied.

Domestic legal systems generally possess highly developed institutions for these purposes.

International law has secondary mechanisms, but they are comparatively decentralised.

Oppenheim’s Approach

L. Oppenheim treated international law as a genuine body of legal rules governing relations among States.

The absence of a central sovereign does not necessarily destroy the legal character of international law.

International law operates within a community of States where legal obligations arise through recognised processes such as treaties and custom.

Kelsen’s Approach

Hans Kelsen approached international law through his Pure Theory of Law.

He rejected the idea that the validity of law necessarily depends upon the existence of a sovereign issuing commands.

According to Kelsen’s approach, international law forms part of a normative legal order.

He considered international law capable of being understood as a genuine legal system and placed significant emphasis on the hierarchical structure of legal norms.

Hart and Austin Compared

Point	Austin	H.L.A. Hart
Definition of law	Command of sovereign backed by sanction	System of primary and secondary rules
International sovereign	Necessary	Not necessary to establish legal character
International law	Positive morality	A form of law, though less institutionally developed
Enforcement	Central to law	Not the sole test of legal validity
International system	Fails command theory	Can constitute a legal system despite structural differences

Why the Absence of a World Government Does Not Destroy International Law

A major criticism of international law is that there is no world government.

However, the existence of a sovereign government is not the only possible basis for a legal system.

International law operates through a decentralised structure involving:

• States;
• treaties;
• customary international law;
• international organisations;
• international courts and tribunals;
• diplomatic processes;
• dispute-settlement mechanisms.

The international system therefore differs from domestic law in institutional structure, not necessarily in legal character.

Enforcement of International Law

International law does not have one universal enforcement mechanism. Instead, enforcement operates through different methods.

State Responsibility

A State that commits an internationally wrongful act may incur international responsibility.

The consequences can include:

• cessation of the wrongful conduct;
• assurances of non-repetition where appropriate;
• reparation;
• restitution;
• compensation;
• satisfaction.

Countermeasures

In circumstances recognised by international law, an injured State may take countermeasures against the responsible State.

Countermeasures are subject to legal limitations and cannot be treated as an unrestricted right of retaliation.

Collective Security

The United Nations Charter establishes a collective security framework.

The Security Council has powers under the Charter to respond to threats to international peace and security, including through measures provided under the Charter.

International Adjudication

International disputes may be submitted to courts or tribunals where an applicable jurisdictional basis exists.

These institutions provide legal interpretation and adjudication even though their jurisdiction is not universally compulsory.

Important Distinction: Enforcement vs Legal Validity

The absence of automatic enforcement should not be confused with the absence of legal validity.

Point	Legal Validity	Enforcement
Meaning	Whether a rule is legally binding	Mechanism used to secure compliance
International law	Rules can be legally binding	Enforcement is decentralised
Domestic law	Generally backed by central institutions	Usually more centralised
Relationship	A rule may be legally valid	Enforcement may vary in effectiveness

A legal system can therefore possess binding rules even where enforcement mechanisms are imperfect.

International Law and Sanctions

Sanctions also demonstrate that international law should not be reduced to the presence of physical coercion.

Possible consequences of violating international law may include:

• legal responsibility;
• reparations;
• countermeasures;
• Security Council measures;
• diplomatic consequences;
• economic consequences;
• loss of international cooperation.

The nature and availability of consequences depend upon the particular rule and circumstances.

Important Cases

S.S. Lotus Case (France v. Turkey), 1927

The Permanent Court of International Justice examined the relationship between State sovereignty and international law.

The case is significant for understanding the decentralised nature of the international legal system and the relationship between State freedom and international legal restrictions.

Nicaragua v. United States, 1986

The International Court of Justice applied customary international law concerning the use of force and non-intervention.

The case demonstrates that international legal rules can operate independently of particular treaty obligations.

North Sea Continental Shelf Cases, 1969

The ICJ examined the formation of customary international law and the significance of State practice and opinio juris.

The case demonstrates that international law contains rules arising through recognised processes other than express treaty consent.

Barcelona Traction, Light and Power Company, Limited, 1970

The ICJ distinguished between obligations owed to particular States and obligations owed to the international community as a whole.

The case illustrates the development of international law beyond a narrow conception based solely on reciprocal State interests.

Important International Instruments

United Nations Charter

The UN Charter provides a central legal framework for contemporary international relations.

It establishes principles concerning sovereign equality, peaceful settlement of disputes, prohibition of the threat or use of force and collective security.

Statute of the International Court of Justice

The ICJ Statute provides the institutional and jurisdictional framework of the Court and identifies the principal legal materials used by the Court in deciding disputes.

Vienna Convention on the Law of Treaties, 1969

The Vienna Convention provides the principal framework governing treaties between States and reflects fundamental principles concerning treaty obligations and interpretation.

Common Confusions

If international law cannot always be enforced, is it still law?

Yes.

Enforcement and legal validity are related but distinct concepts. International law contains binding rules even though enforcement is decentralised.

Does international law have no sanctions?

No.

International law provides various legal and institutional consequences for violations, although these differ from domestic criminal or administrative enforcement.

Does the absence of a world sovereign mean international law is invalid?

No.

The absence of a supreme international sovereign distinguishes international law from many domestic legal systems but does not by itself negate its legal character.

Is international law based entirely on State consent?

No.

Consent is important, particularly in treaty law, but customary international law, general principles and peremptory norms cannot all be explained simply through express consent.

Is international law merely international morality?

No.

International morality may influence international law, but international law has recognised legal sources, obligations and consequences.

Modern Position

The modern position is that international law is law, although it is structurally different from domestic law.

The absence of a central sovereign, legislature and universal enforcement authority should be understood as characteristics of the international legal system rather than proof that no legal system exists.

International law operates through a combination of:

• treaties;
• customary international law;
• general principles of law;
• international institutions;
• judicial and arbitral mechanisms;
• State practice;
• legal responsibility;
• collective mechanisms.

Its effectiveness may vary depending upon political circumstances and institutional limitations, but effectiveness and legal validity are not identical concepts.

Topic at a Glance

Point	Position
Central question	Whether international law possesses genuine legal character
Main critic	John Austin
Austin’s view	International law is positive morality rather than positive law
Major modern response	International law is a genuine but decentralised legal system
Hart’s approach	International law consists primarily of primary rules and has less-developed secondary institutions
Main difficulty	Absence of a central sovereign and universal enforcement authority
Modern position	International law is recognised as a legal system
Enforcement	Decentralised and varied
Key concepts	State consent, custom, treaties, responsibility, adjudication and collective security
Important cases	Lotus, North Sea Continental Shelf, Nicaragua, Barcelona Traction

Quick Revision

• The debate asks whether international law qualifies as genuine law.
• John Austin argued that law requires the command of a sovereign backed by sanctions.
• Because there is no supreme sovereign over States, Austin regarded international law as positive morality.
• The absence of a world legislature and centralised enforcement has traditionally been used to challenge the legal character of international law.
• Modern scholars reject the idea that centralised coercion is the only test of legal validity.
• H.L.A. Hart accepted international law as law but recognised its less-developed institutional structure.
• International law contains primary rules imposing obligations upon States and other recognised actors.
• Treaties and customary international law create legally binding obligations.
• International law has enforcement mechanisms, although they are decentralised.
• State responsibility can result from internationally wrongful conduct.
• Countermeasures may be available in circumstances recognised by international law.
• The UN Charter provides collective security mechanisms.
• International courts and tribunals apply international law within their respective jurisdictional frameworks.
• The absence of universal compulsory jurisdiction does not by itself negate the existence of international law.
• International law cannot be reduced entirely to State consent.
• Jus cogens demonstrates the existence of norms that cannot be displaced through ordinary agreement.
• The modern view is that international law is a genuine legal system with a decentralised institutional structure.

Conclusion

The question of whether international law is really law arises largely because international law differs from domestic law in its institutional structure and enforcement mechanisms. Austin’s command theory provides a powerful classical criticism, but it does not adequately account for the nature of modern international legal obligations. States routinely recognise, invoke and apply international legal rules, while treaties, customary international law, international courts, State responsibility and collective mechanisms provide an established legal framework. International law may lack the centralised machinery of a domestic legal system, but that difference does not deprive it of its legal character. The better modern view is therefore that international law is law, though it operates through a distinctive and decentralised international legal order.