Conflict of Laws vs. International Law

Conflict of Laws vs. International Law

Understanding the Difference Between Private Cross-Border Disputes and the Law Governing Relations Among States

The terms Conflict of Laws and International Law are often used together because both can involve legal questions crossing national or jurisdictional boundaries. A dispute may involve a foreign country, an international transaction, a multinational company, or individuals who live in different countries. Yet the two fields address fundamentally different legal problems.

The central distinction is this:

Conflict of laws primarily asks which jurisdiction’s law should govern a private legal dispute, while public international law primarily governs legal relationships involving states and other international actors.

For example, if an American consumer enters into a contract with a French company and a dispute arises over payment, a court may have to determine which country’s law governs the contract. That is a conflict-of-laws question.

By contrast, if France and the United States enter into a treaty concerning international obligations, the interpretation and performance of that treaty may raise questions of public international law.

The distinction is not always absolute. Modern international commerce, human rights, investment, arbitration, international family relationships, and transnational litigation frequently cause the two fields to intersect.

Nevertheless, understanding their different purposes is essential.

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What Is Conflict of Laws?

Conflict of laws is the body of legal rules and principles used when a legal dispute has connections to more than one jurisdiction.

In the United States, this most commonly occurs when the laws of two or more states may potentially govern a dispute.

For example, consider a collision between two vehicles:

• the plaintiff lives in Pennsylvania;
• the defendant lives in New York;
• the accident occurs in New Jersey; and
• the lawsuit is filed in Pennsylvania.

The dispute may therefore be connected to several jurisdictions.

The court may need to determine which state’s law governs questions such as liability or damages.

That is a choice-of-law problem.

Conflict of laws can also arise internationally. A contract between a company in California and a company in Germany may raise questions about whether California law, German law, or another jurisdiction’s law governs the agreement.

Cornell’s Legal Information Institute explains that conflict of laws concerns situations in which the laws of two or more jurisdictions may apply to a case and the outcome may depend upon which jurisdiction’s law is applied. Cornell Wex — Conflict of Laws

The field is therefore concerned primarily with competing legal systems and the selection of the applicable law.

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What Is International Law?

International law is a broader field concerning rules governing conduct and relationships across national boundaries.

When lawyers use the term “international law,” they often mean public international law: the body of legal principles governing relations among states and other entities recognized as having international legal personality.

Public international law addresses subjects such as:

• treaties;
• diplomatic relations;
• state responsibility;
• international organizations;
• international humanitarian law;
• the use of force;
• international human rights;
• the law of the sea;
• international environmental obligations;
• international criminal law; and
• the recognition and legal consequences of certain acts of states.

The central actors are therefore often states, rather than private individuals or companies.

An international dispute between two governments is fundamentally different from a private lawsuit between two companies located in different countries.

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The Simplest Way to Distinguish the Two

The difference can be expressed through two questions.

Conflict of Laws asks:

Which jurisdiction’s law applies to this private dispute?

Public International Law asks:

What legal rules govern the conduct and relationships of states and other international actors?

This distinction provides a useful starting point.

Imagine that a Bulgarian citizen enters into a commercial agreement with an American company.

If the dispute concerns whether the company breached the contract, the court may need to determine which country’s or state’s private law applies.

That is a conflict-of-laws issue.

Now imagine that the United States and Bulgaria enter into a treaty establishing certain obligations between the two governments.

Questions concerning the interpretation, performance, or breach of that treaty are primarily questions of international law.

The participants, legal sources, institutions, and applicable doctrines are different.

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Private International Law and Public International Law

The terminology can become confusing because the expression private international law is frequently used as another name for conflict of laws.

In many legal systems, particularly outside the United States, the phrase private international law describes rules dealing with private disputes that contain an international element.

These rules may concern:

• international jurisdiction;
• applicable law;
• recognition of foreign judgments;
• international family disputes;
• cross-border contracts;
• international torts;
• international commercial transactions; and
• other private relationships extending across national borders.

By contrast, public international law concerns the legal relations of states and other international actors.

Thus, a useful conceptual division is:

Private international law → cross-border private relationships.

Public international law → international relations involving states and other international legal actors.

In the United States, “conflict of laws” is often used where another legal system might speak of “private international law.”

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The Parties Are Different

One of the clearest differences between the fields concerns the parties involved.

Conflict-of-laws disputes usually involve private parties.

These may include:

• individuals;
• companies;
• employers and employees;
• insurers;
• business partners;
• spouses;
• property owners; or
• other private legal persons.

For example, two corporations may disagree about a contract performed in several countries.

International law, by contrast, traditionally focuses on states and international institutions.

States may enter into treaties, assert international claims, incur international responsibility, or participate in international proceedings.

International organizations can also play an important role.

In some areas of international law, individuals have become increasingly important as rights-holders or potential subjects of international responsibility. Human rights law and international criminal law are particularly important examples.

Nevertheless, this development does not eliminate the fundamental distinction between public international law and private conflict-of-laws rules.

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The Sources of Law Are Different

Another important distinction concerns the sources from which the applicable rules originate.

Conflict-of-laws rules may come from:

• state statutes;
• state judicial decisions;
• common-law principles;
• federal statutes;
• constitutional principles;
• procedural rules;
• contractual provisions; and
• applicable international conventions.

The exact rules depend upon the jurisdiction and the nature of the dispute.

International law has a different traditional source structure.

The Statute of the International Court of Justice, for example, identifies treaties, international custom, and general principles of law among the principal sources considered by the Court, while judicial decisions and scholarly writings may serve as subsidiary means for determining rules of law.

This demonstrates an important difference in legal architecture.

A state court deciding a private contract dispute may be applying the conflict-of-laws rules of the relevant state.

An international tribunal addressing a dispute between states may instead be applying rules of international law.

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A Conflict of Laws Example

Consider this hypothetical:

A company incorporated in Delaware enters into a contract with a company based in Italy.

The agreement is negotiated through representatives located in New York and Milan. The products are manufactured in Italy and delivered to the United States. The contract contains no choice-of-law provision.

A dispute arises concerning whether one party breached the contract.

A court may have to determine:

• where the contract was formed;
• where it was performed;
• where the parties are located;
• which jurisdiction has the most significant relationship to the dispute;
• whether a particular country’s law should apply; and
• whether foreign law should be applied by the forum court.

This is primarily a conflict-of-laws problem.

The fact that Italy and the United States are involved does not automatically transform the dispute into a matter of public international law.

The parties are private companies, and the underlying dispute concerns their private contractual rights.

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An International Law Example

Now consider a different hypothetical.

The United States and Italy enter into an international treaty concerning maritime cooperation.

A dispute arises concerning whether one government has complied with an obligation imposed by the treaty.

The dispute concerns the obligations of sovereign states under an international agreement.

That is fundamentally a public international law problem.

The questions might include:

• What does the treaty require?
• How should the treaty be interpreted?
• Has one state breached an international obligation?
• What consequences follow from the breach?
• Is there an applicable dispute-resolution mechanism?
• Does an international tribunal have jurisdiction?

These are substantially different questions from determining which state’s private law governs a commercial contract.

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The Role of Courts

Conflict-of-laws questions are commonly resolved by domestic courts.

A state court or federal court may determine which jurisdiction’s law applies to a dispute before it.

For example, a New York court might determine that California law governs a particular issue even though the litigation is taking place in New York.

Similarly, a U.S. federal court may have to determine which state’s substantive law applies to a state-law claim.

International-law disputes can also be heard by domestic courts, but they may additionally be addressed by international courts and tribunals.

The International Court of Justice, for example, hears disputes between states that fall within its jurisdiction.

Other international tribunals and dispute-resolution mechanisms have jurisdiction over particular categories of international disputes.

The institutional structure is therefore substantially different.

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Jurisdiction Means Different Things in the Two Fields

The word jurisdiction appears in both fields, but its context can be very different.

In conflict of laws, a court may ask:

Does this state or federal court have jurisdiction over the defendant or dispute?

If jurisdiction exists, the court may then ask:

Which jurisdiction’s substantive law applies?

These are separate questions.

In international law, jurisdiction can involve the authority of one state to regulate conduct or exercise legal authority in relation to persons, territory, vessels, events, or conduct with international implications.

International tribunals may also have jurisdiction based upon treaties, agreements, declarations, or other accepted forms of consent.

Thus, although the word is identical, the legal context must be carefully identified.

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Foreign Law Is Not the Same as International Law

A particularly important distinction is that foreign law is not automatically international law.

Suppose a U.S. court determines that German contract law applies to a dispute.

The court may then have to consider the content of German law.

German contract law is foreign domestic law from the perspective of the U.S. court.

It is not automatically a rule of public international law merely because it comes from another country.

This distinction is crucial.

Every sovereign state has its own domestic legal system. When a court in one jurisdiction applies another country’s domestic law under its conflict-of-laws rules, the foreign law does not thereby become international law.

The court is simply applying the law that its conflict-of-laws analysis has determined to be applicable.

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Treaties Can Connect the Two Fields

The distinction becomes more complicated when an international treaty affects a private dispute.

International conventions may establish rules concerning:

• international sales;
• arbitration;
• child abduction;
• recognition of judgments;
• service of legal documents;
• evidence;
• transportation;
• intellectual property; and
• other cross-border relationships.

In such circumstances, international law and conflict of laws may intersect.

A private dispute can therefore be influenced by an international agreement even though the parties themselves are private individuals or businesses.

The existence of an international treaty does not, however, mean that every issue in the resulting private dispute becomes a question of public international law.

The lawyer must identify precisely what legal question is being answered and what legal instrument supplies the rule.

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Recognition of Foreign Judgments

Another area where the two fields come close is the recognition and enforcement of foreign judgments.

Imagine that a company obtains a judgment in a French court against an American company and later seeks to enforce that judgment in the United States.

A U.S. court may have to determine whether the foreign judgment should be recognized and enforced.

This involves questions concerning:

• jurisdiction of the foreign court;
• procedural fairness;
• notice;
• finality;
• public policy;
• applicable recognition rules; and
• potentially international conventions.

This is generally treated as part of private international law or conflict of laws rather than as a dispute between states under public international law.

Yet international agreements can influence the applicable rules.

This is an excellent example of how the two fields can overlap without becoming identical.

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International Human Rights Law Is Different From Conflict of Laws

International human rights law provides another useful contrast.

Suppose an international instrument recognizes a right to freedom of expression or protection against discrimination.

The question may be whether a state has complied with an international obligation concerning human rights.

That is fundamentally an issue of international law.

By contrast, suppose two private parties dispute whether a particular state’s discrimination law applies to their employment relationship because the employee works in one state while the employer is based in another.

The court may be facing a conflict-of-laws question.

The subject matter may appear similar, but the legal question is different.

One asks:

What international obligation binds the state?

The other asks:

Which domestic legal system governs the private relationship?

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International Criminal Law Also Has a Different Structure

International criminal law illustrates another important distinction.

International criminal law addresses certain offenses of international concern, including crimes such as genocide, crimes against humanity, and war crimes.

These rules may create individual criminal responsibility under international law.

Conflict of laws, by contrast, generally concerns the selection of applicable law in private legal disputes.

A criminal prosecution in a domestic court involving conduct occurring in another state can certainly raise jurisdictional and choice-of-law questions, but that does not automatically make the prosecution an international-law proceeding.

Again, the nature of the legal question matters.

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Why the Distinction Matters in the United States

The distinction is particularly important for understanding the American legal system.

The United States contains multiple domestic jurisdictions.

Every state has its own legal rules, and the federal government has its own legal authority.

Therefore, a significant portion of American conflict-of-laws doctrine concerns interstate conflicts rather than international disputes.

A lawsuit involving California and New York can present a conflict-of-laws question even though no foreign country is involved.

This is one reason why “conflict of laws” is broader than merely “international law.”

A dispute between two American parties may involve conflict of laws because the parties or events are connected to different states.

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Conflict of Laws Can Exist Without Any International Element

Consider a simple example.

John lives in Texas.

Sarah lives in Oklahoma.

They enter into a contract in Oklahoma concerning property located in Texas. The contract is performed in Texas, but the lawsuit is filed in Oklahoma.

No foreign country is involved.

Nevertheless, multiple jurisdictions have legitimate connections to the dispute.

The court may have to decide whether Texas or Oklahoma law governs particular issues.

That is unquestionably a conflict-of-laws problem.

Therefore:

Conflict of laws does not require an international dispute.

International law, by contrast, derives its distinctive character from the international legal order and its relationships among states and other international actors.

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International Law Can Exist Without a Conflict of Laws

The reverse is also true.

Suppose the United States and Canada enter into a treaty concerning environmental cooperation.

The treaty creates obligations between the two governments.

There may be no private dispute requiring a court to choose between competing domestic laws.

Nevertheless, international law governs the treaty relationship.

Therefore:

International law does not require a private choice-of-law problem.

The two fields can overlap, but neither is simply a subdivision of the other.

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A Useful Comparison

Issue	Conflict of Laws	Public International Law
Primary concern	Which jurisdiction’s law applies?	What rules govern international legal relations?
Typical parties	Individuals and private entities	States and international actors
Geographic scope	Interstate or international	Primarily international
Main problem	Competing jurisdictions or laws	International rights, duties, and obligations
Common institutions	Domestic courts	International courts, tribunals, and organizations
Major sources	Domestic statutes, cases, common law, contracts, applicable conventions	Treaties, customary international law, general principles, and other recognized sources
Example	Which state’s contract law governs?	Has a state violated a treaty?
Foreign law	May be selected as applicable law	Not the central concept
Private international law	Closely related / often synonymous	Distinct from public international law

The table is a simplification, but it provides a useful conceptual framework.

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The Important Middle Ground: Private International Law

The distinction becomes most difficult when dealing with private international law.

Private international law is concerned with private disputes containing an international element.

It can include three major questions:

1. Jurisdiction

Which country’s courts have authority to hear the dispute?

2. Choice of law

Which country’s law should govern the dispute?

3. Recognition and enforcement

Should a judgment or other legal determination from another country be recognized and enforced?

These questions resemble traditional conflict-of-laws problems.

That is why many legal scholars and legal systems treat private international law as essentially the international dimension of conflict of laws.

The terminology varies, but the underlying concept is consistent: a private legal relationship crosses jurisdictional boundaries, and the legal system must determine how that relationship should be handled.

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Why Terminology Can Be Confusing

Legal terminology varies significantly between countries.

In the United States, lawyers commonly use conflict of laws to describe the field.

In many other countries, the expression private international law is more common.

The phrase “international law,” however, often refers to public international law, particularly in American legal education.

Consequently, the following distinction is useful:

Conflict of Laws / Private International Law
→ Which jurisdiction’s law applies to a private cross-border dispute?

Public International Law
→ What legal rules govern relations among states and other international actors?

This terminology is not perfectly uniform across every legal tradition, but it is an excellent starting point for understanding the difference.

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Why the Two Fields Sometimes Overlap

Modern legal disputes frequently cross several legal boundaries at once.

Consider an international commercial dispute involving:

• a U.S. corporation;
• a German corporation;
• a contract governed by English law;
• arbitration in Switzerland;
• products manufactured in China; and
• enforcement proceedings in the United States.

Such a dispute may involve:

• conflict of laws;
• international commercial law;
• arbitration law;
• treaty obligations;
• recognition of foreign judgments or awards;
• domestic procedural law; and
• public international law principles.

The modern legal environment therefore does not always permit perfect separation between fields.

The correct approach is not to assume that every cross-border dispute is “international law.”

Instead, the lawyer must identify the specific legal question being asked.

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A Practical Method for Identifying the Field

When confronted with a cross-border legal problem, ask four questions.

First: Who are the parties?

Are they private individuals or companies?

Or are governments and international organizations involved?

Second: What is the dispute about?

Is it a private contract, tort, family matter, property dispute, or commercial relationship?

Or does it concern a treaty, state responsibility, diplomatic relations, armed conflict, or another international obligation?

Third: What legal question must be answered?

Is the question:

Which law applies?

Or is it:

What international obligation exists?

Fourth: Which legal institution is being asked to resolve the matter?

Is the dispute before a state court or federal court?

Or is it before an international court, tribunal, arbitral body, or other international institution?

These questions will often reveal whether the problem primarily belongs to conflict of laws, public international law, or the important area where the two overlap.

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Conflict of Laws and International Law Can Work Together

It would be a mistake to treat the two fields as completely isolated.

A sophisticated cross-border dispute may require lawyers to use both.

For example, an international convention may influence the rules governing a private dispute. A treaty may require states to recognize certain rights or establish particular procedures. A domestic court may then apply those rules while simultaneously using conflict-of-laws principles to determine which domestic law governs issues not resolved by the international instrument.

The relationship can therefore be understood as layered.

International law may establish international obligations or frameworks.

Conflict-of-laws rules may determine which domestic legal system governs a private dispute within that framework.

Understanding which layer supplies which rule is essential.

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Key Takeaways

• Conflict of laws and international law are related but distinct fields.
• Conflict of laws primarily addresses situations in which more than one jurisdiction’s law may apply to a private dispute.
• Public international law primarily governs relations among states and other international legal actors.
• Conflict-of-laws disputes can occur entirely within the United States, such as disputes between Texas and Oklahoma.
• International law can apply even when there is no private dispute requiring a choice between domestic laws.
• Private international law is often used as another term for the international dimension of conflict of laws.
• Foreign domestic law is not the same thing as international law.
• A U.S. court may apply foreign law without transforming that foreign law into a rule of public international law.
• Treaties and international conventions can create points of contact between conflict of laws and international law.
• Recognition and enforcement of foreign judgments can involve both domestic conflict-of-laws principles and international agreements.
• The identity of the parties, the nature of the dispute, the legal question, and the institution resolving it help determine which field is involved.
• A single sophisticated cross-border dispute may involve conflict of laws, private international law, and public international law at the same time, but each addresses a different aspect of the problem.

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Frequently Asked Questions

Is conflict of laws part of international law?

Not necessarily. Conflict of laws is generally treated as a distinct field dealing with competing jurisdictions and applicable law. Its international dimension is often called private international law.

Is conflict of laws only about foreign countries?

No. Conflict of laws frequently concerns disputes between U.S. states. A case involving Texas and New York can present a conflict-of-laws issue even though no foreign country is involved.

What is the difference between conflict of laws and private international law?

The terms are often used in substantially similar ways. “Conflict of laws” is especially common in American legal terminology, while “private international law” is widely used internationally.

What is the difference between private international law and public international law?

Private international law concerns private relationships containing a cross-border element, such as international contracts or family disputes. Public international law primarily concerns legal relations among states and other international actors.

Is foreign law international law?

No. Foreign law is the domestic law of another country. A court may apply foreign domestic law under its conflict-of-laws rules without treating that law as public international law.

Can a U.S. court apply the law of another country?

Yes. Depending on the applicable conflict-of-laws rules, a U.S. court may determine that the law of a foreign country governs a particular issue.

Do treaties belong to conflict of laws or international law?

Treaties are traditionally a source of international law, but some treaties establish rules that directly affect private cross-border disputes. In those circumstances, treaty law and conflict-of-laws principles can intersect.

Can one case involve both fields?

Yes. A cross-border dispute may involve private choice-of-law questions while also being affected by treaties or other international-law rules.

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Conclusion

Conflict of laws and international law meet at the borders of legal systems, but they ask different questions.

Conflict of laws asks which legal system should govern a particular private dispute.

Public international law asks what rules govern the international legal relationships of states and other international actors.

The distinction is particularly important because the presence of an international element does not automatically transform a private dispute into a matter of international law. A contract between companies from different countries may still principally present a conflict-of-laws problem. Conversely, a treaty dispute between two governments may be governed by public international law without presenting a traditional choice-of-law question.

Between these two fields lies private international law, which deals with private legal relationships crossing national boundaries and often encompasses questions of international jurisdiction, applicable law, and recognition of foreign judgments.

The modern world increasingly produces disputes that cross these boundaries. As commerce, families, employment, property ownership, technology, and financial relationships become increasingly international, lawyers must be able to identify which legal system supplies the relevant rule—and which legal field provides the framework for answering that question.

That is the essential distinction between conflict of laws and international law.