Public International Law and Private International Law

International law is broadly concerned with legal relationships that cross national boundaries. It is commonly divided into two broad areas: Public International Law and Private International Law. Although both deal with international elements, their subject matter, parties, sources, jurisdictional questions and methods of resolving disputes are different.

Public International Law primarily regulates relations between States and other entities recognised under international law. Private International Law, on the other hand, deals with private relationships containing a foreign or international element and determines which country’s courts and laws should apply.

Understanding this distinction is essential because the expression “international law” can refer to fundamentally different legal problems depending on whether the dispute concerns States and international institutions or private persons and commercial relationships across borders.

Meaning of Public International Law

Public International Law is the body of legal rules and principles governing relations among States and other entities possessing international legal personality.

Traditionally, States were regarded as the principal subjects of Public International Law. Its modern scope has expanded to include international organisations and, in particular fields, individuals.

Public International Law deals with matters such as:

• State sovereignty;
• diplomatic relations;
• treaties;
• international peace and security;
• use of force;
• State responsibility;
• international human rights;
• international humanitarian law;
• law of the sea;
• international environmental law;
• international criminal law;
• international dispute settlement.

The United Nations Charter, treaties, customary international law and general principles of law are among the important foundations of the modern international legal system.

Meaning of Private International Law

Private International Law is the branch of law concerned with private legal relationships involving a foreign element.

It is also commonly referred to as Conflict of Laws.

A foreign element may arise because:

• the parties are citizens of different countries;
• the parties are domiciled in different countries;
• a contract was made in one country and performed in another;
• property is situated in a foreign country;
• a marriage was entered into abroad;
• a tort occurred in another country;
• proceedings have already been instituted in a foreign court.

Private International Law determines which legal system should govern the dispute and which court should hear it.

Example

Suppose an Indian company enters into a contract with a French company. The contract is signed in India, requires performance in France and contains no clear choice-of-law clause. A dispute subsequently arises.

The questions may include:

• Which country’s court has jurisdiction?
• Which country’s law governs the contract?
• Will an Indian court recognise a French judgment?
• Will a French court recognise an Indian judgment?

These are questions of Private International Law, not Public International Law.

Main Questions in Private International Law

Private International Law traditionally addresses three principal questions.

1. Jurisdiction

Which country’s court has authority to hear the dispute?

2. Choice of Law

Which country’s law should the court apply?

3. Recognition and Enforcement of Foreign Judgments

Will a judgment or order issued by a foreign court be recognised and enforced by another country’s courts?

These three questions form the central framework of Conflict of Laws.

Nature of Public International Law

Public International Law has a genuinely international character.

It regulates relationships that operate at the international level and derives from recognised international legal sources.

Its principal characteristics include:

• State sovereignty;
• international legal personality;
• treaties;
• customary international law;
• international institutions;
• international dispute settlement;
• decentralised enforcement.

The parties may include States, international organisations and, in certain areas, individuals.

Nature of Private International Law

Private International Law is different in character.

Despite its name, it is not necessarily a universal body of law enacted by an international legislature. It primarily consists of domestic rules of each State dealing with international private disputes, supplemented in some areas by international conventions and regional instruments.

For example, Indian courts apply Indian rules concerning jurisdiction, applicable law and recognition of foreign judgments when deciding a cross-border private dispute.

Thus, Private International Law operates largely through domestic legal systems.

Basis of Public International Law

Public International Law derives from recognised international legal sources, including:

• treaties;
• customary international law;
• general principles of law;
• judicial decisions and scholarly writings as subsidiary means for determining rules of law.

The international legal system also contains specialised rules created through international organisations and particular treaty regimes.

Basis of Private International Law

Private International Law primarily derives from:

• domestic legislation;
• judicial decisions;
• procedural rules;
• principles developed by courts;
• international conventions;
• bilateral and multilateral agreements;
• regional legal instruments where applicable.

The precise rules therefore differ from one country to another.

Subjects

Public International Law

The principal subjects include:

• States;
• international organisations;
• individuals in certain areas;
• other entities possessing international legal personality.

Private International Law

The parties are generally private persons or private entities, including:

• individuals;
• companies;
• corporations;
• partnerships;
• other private organisations.

Governments can sometimes become parties to private-law relationships, but the legal character of the dispute must be examined to determine whether it belongs to Public or Private International Law.

Subject Matter

Public International Law

Public International Law concerns matters such as:

• State sovereignty;
• international peace and security;
• diplomatic relations;
• treaties;
• human rights;
• international humanitarian law;
• international criminal law;
• international environmental law;
• maritime law;
• State responsibility.

Private International Law

Private International Law primarily concerns:

• contracts;
• marriage and divorce;
• succession;
• property;
• commercial transactions;
• torts;
• family relationships;
• corporate disputes;
• foreign judgments;
• jurisdiction;
• applicable law.

Jurisdiction

The concept of jurisdiction operates differently in the two branches.

In Public International Law

Jurisdiction concerns the authority of States and international courts in matters governed by international law.

For States, jurisdiction may be based on principles such as:

• territoriality;
• nationality;
• passive personality;
• protective jurisdiction;
• universality.

International courts have jurisdiction according to the legal basis provided by their governing instruments or accepted jurisdictional arrangements.

In Private International Law

Jurisdiction asks whether the court of a particular country can hear a private dispute containing a foreign element.

The court may consider factors such as:

• residence or domicile of the defendant;
• place where the contract was made;
• place of performance;
• location of property;
• place where a wrongful act occurred;
• contractual jurisdiction clauses.

Applicable Law

One of the most important differences concerns the determination of applicable law.

Public International Law

The applicable rules are international legal rules, such as:

• treaty provisions;
• customary international law;
• general principles of law;
• other applicable international rules.

Private International Law

The court may have to choose between the laws of different countries.

For example, a court may have to decide whether Indian law, English law or Singaporean law governs a particular contract.

The rules used to make that determination are called choice-of-law rules or conflict-of-laws rules.

Recognition and Enforcement of Foreign Judgments

Recognition and enforcement of foreign judgments are major areas of Private International Law.

Suppose a French court gives judgment against an Indian company.

An Indian court may subsequently have to determine whether the French judgment can be recognised and enforced in India.

The question is not whether France has violated international law. Instead, it concerns the domestic legal rules governing the effect of a foreign judgment.

This is therefore primarily a Private International Law question.

Important Distinctions

Point	Public International Law	Private International Law
Basic meaning	Governs international legal relations	Governs private relationships containing a foreign element
Traditional parties	States	Private individuals and entities
Other participants	International organisations and, in certain areas, individuals	Companies, individuals and other private entities
Main concern	International rights and obligations	Jurisdiction, applicable law and foreign judgments
Principal legal system	International legal order	Domestic legal systems, supplemented by international instruments
Main sources	Treaties, custom and general principles	Domestic legislation, judicial decisions and international conventions
Sovereignty	Central concept	Usually indirect
Jurisdiction	State and international jurisdiction	Jurisdiction of domestic courts
Applicable law	International law	Law selected through conflict-of-laws rules
Disputes	Often inter-State or international	Usually private disputes with a foreign element
Example	Dispute concerning treaty obligations between States	Cross-border contractual dispute
Enforcement	International and decentralised mechanisms	Domestic courts and enforcement procedures

Public International Law vs Private International Law: Key Differences

1. Nature of Parties

Public International Law primarily deals with States and other international legal persons.

Private International Law generally concerns private parties.

2. Nature of Dispute

Public International Law deals with international legal disputes.

Private International Law deals with private disputes containing an international or foreign element.

3. Source of Rules

Public International Law derives principally from international legal sources.

Private International Law largely derives from the domestic law of the forum State, although international conventions can harmonise particular areas.

4. Role of Sovereignty

State sovereignty is a fundamental principle of Public International Law.

In Private International Law, sovereignty appears primarily through questions concerning the jurisdiction and law of different States.

5. Main Legal Questions

Public International Law asks questions such as:

• What obligations does a State have under international law?
• Has a State breached an international obligation?
• Is the use of force lawful?
• Does an international court have jurisdiction?

Private International Law asks:

• Which court should hear the case?
• Which country’s law applies?
• Should a foreign judgment be recognised?
• How should a cross-border private dispute be resolved?

Relationship Between Public and Private International Law

Although they are distinct branches, Public International Law and Private International Law are not completely unrelated.

International Treaties

International treaties may establish uniform rules governing private relationships.

For example, international conventions may regulate:

• international commercial transactions;
• carriage of goods;
• international child abduction;
• recognition of foreign judgments;
• arbitration.

Such treaties are products of international law but may directly affect private legal relationships.

State Responsibility

A private dispute may sometimes raise issues of State responsibility if governmental conduct is involved.

However, the mere fact that a State is involved does not automatically transform a private dispute into one governed by Public International Law.

International Commercial Arbitration

International commercial arbitration occupies an important space connecting the two areas.

Private parties may resolve disputes through arbitration, while the legal framework governing arbitration may be established through international conventions and domestic legislation.

Important Concepts in Private International Law

Foreign Element

A foreign element exists when a private legal relationship is connected with more than one country.

This may arise through:

• nationality;
• domicile;
• residence;
• location of property;
• place of contract;
• place of performance;
• place of injury.

Lex Fori

Lex fori means the law of the forum or court hearing the dispute.

The court generally applies its own procedural law, subject to applicable legal rules.

Lex Loci

Lex loci refers broadly to the law of the place connected with the relevant event or relationship.

Different formulations include:

• lex loci contractus — law of the place where a contract was made;
• lex loci delicti — law of the place where a tort occurred;
• lex situs — law of the place where property is situated.

Domicile

Domicile can be an important connecting factor in determining applicable law and jurisdiction in certain private international law disputes.

Choice of Law

Choice of law refers to the process of determining which country’s substantive law governs a dispute involving multiple legal systems.

Important Cases

Government of India v. Taylor, 1955

The Supreme Court of India considered the enforceability of foreign tax claims and the principle that courts generally do not enforce the revenue laws of another country.

The case illustrates the limits placed on the enforcement of foreign governmental claims.

Satya v. Teja Singh, 1975

The Supreme Court of India considered the recognition of a foreign divorce decree and examined issues concerning jurisdiction and the recognition of foreign judgments.

The case is important in understanding the application of Private International Law principles by Indian courts.

Y. Narasimha Rao v. Y. Venkata Lakshmi, 1991

The Supreme Court of India examined the recognition of a foreign matrimonial judgment and the circumstances in which a foreign judgment may be recognised by Indian courts.

The decision is particularly significant in the context of foreign matrimonial decrees.

Common Confusions

Are Public International Law and Private International Law the same?

No.

Public International Law primarily governs international legal relations involving States and other international legal persons, while Private International Law addresses private relationships containing a foreign element.

Does Private International Law actually constitute international law?

It depends on the sense in which the expression is used.

Much of Private International Law consists of domestic conflict-of-laws rules. International conventions may also create common rules for participating States.

Is every case involving a foreign country a Public International Law dispute?

No.

A contract between an Indian company and a foreign company is ordinarily a private-law relationship. Questions about jurisdiction and applicable law may therefore fall within Private International Law.

If a government is a party, is the dispute automatically governed by Public International Law?

No.

The legal character of the relationship must be examined. States can enter into private or commercial transactions, and such disputes may involve private international law principles.

Is recognition of a foreign judgment a matter of Public International Law?

Generally, no.

The recognition and enforcement of foreign judgments are primarily questions of Private International Law, although international treaties may regulate aspects of the process.

Topic at a Glance

Point	Public International Law	Private International Law
Main focus	International legal relations	Private cross-border relationships
Principal parties	States and international legal persons	Individuals and private entities
Key questions	International rights, obligations and responsibility	Jurisdiction, choice of law and recognition
Sources	Treaties, custom, general principles	Domestic law, judicial decisions and conventions
Governing framework	International legal order	Domestic conflict-of-laws system
Typical example	State responsibility for breach of international law	Cross-border contract dispute
Common name	Public International Law	Conflict of Laws

Quick Revision

• Public International Law regulates international legal relations, traditionally between States.
• Private International Law deals with private relationships containing a foreign element.
• Private International Law is also called Conflict of Laws.
• Public International Law primarily asks what international rights and obligations exist.
• Private International Law primarily asks:
  1. Which court has jurisdiction?
  2. Which country’s law applies?
  3. Will a foreign judgment be recognised and enforced?
• Public International Law is primarily based on international legal sources such as treaties and customary international law.
• Private International Law largely consists of domestic conflict-of-laws rules, supplemented by international conventions.
• Sovereignty is central to Public International Law but operates more indirectly in Private International Law.
• Lex fori means the law of the forum.
• Lex situs refers to the law of the place where property is situated.
• A foreign element may arise from nationality, domicile, residence, property, contract, performance or the place of a wrongful act.
• A cross-border contract between private companies generally raises Private International Law issues.
• A dispute between States concerning treaty obligations generally raises Public International Law issues.
• The two branches can overlap through international conventions, international commercial arbitration and other cross-border legal mechanisms.
• A dispute involving a State is not automatically a Public International Law dispute.

Conclusion

Public International Law and Private International Law address different dimensions of international legal relationships. Public International Law primarily regulates States, international organisations and other recognised international actors, while Private International Law deals with private relationships connected with more than one legal system. The former focuses on international rights, obligations and responsibility; the latter focuses mainly on jurisdiction, choice of law and recognition of foreign judgments. Although distinct, the two branches increasingly interact as international commerce, migration, family relationships and cross-border transactions continue to expand.