DIFFERENCES: PRIVATE INTERNATIONAL LAW AND PUBLIC INTERNATIONAL LAW - 16 PJP 21 (2024)

RECOMMENDED CITATION: DELA PEÑA, Mark Angelo S. (2024), “Differences: Private International Law and Public International Law,” 16 PJP 21, available at <insert link> (last accessed on <date>).

ABOUT THE AUTHOR/S: Mark Angelo S. Dela Peña is a lawyer, court litigator, and law professor.

LAST REVISION: [None].

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Public international law deals with rights, obligations, and interactions between and among states and international actors concerning their membership in the community of nations. On the other hand, private international law deals with the study of the determination, analysis, and application of the proper law -- whether domestic law or foreign law -- on a given set of facts with a foreign element, affecting contracts, property, obligations, and other private transactions between private individuals.

A discussion of what “foreign element” means will be made in a separate journal. At this point, suffice it to say that a foreign element is a factual, not legal, situation that may involve the citizenship of parties, the location of the property, and, among others, the place of occurrence of the wrong. The existence of a foreign element takes the case out of the realm of ordinary cases and puts it within the purview of conflict of laws.

From the first paragraph, it becomes clear that public international law is a whole other world than private international law. The principles behind each subject, the subjects or parties involved, the sources of law, and the remedy or manner of resolution of disputes are totally different.

It is error to think that private international law and public international law are two branches of international law because the first is a civil law subject while the second is a political law subject. While both fields deal with legal issues that transcend national borders, they differ significantly in their scope, subjects, and sources.

As to scope, the first is concerned with the resolution of private legal disputes that have an international element, such as contracts, torts, family law, and succession. On the other hand, the second involves the relationships between states, international organizations, and other subjects of international law.

As to subjects, the first deals with individuals, corporations, and other private entities. Whereas, the second deals with states, international organizations, and other entities recognized as subjects of international law.

As to sources, the first is derived from domestic laws of individual states, with some international treaties and conventions providing guidance. On the flip side, the second derived from international treaties, international customs, general principles of law recognized by civilized nations, judicial decisions, and the teachings of qualified publicists

When I teach private international law in law school, I emphasize the distinct nature of this field compared to public international law. I explain that, while both branches of law deal with so-called "international matters," they have fundamentally different scopes, subjects, and sources.

I make sure that my students understand that private international law is primarily concerned with the resolution of private legal disputes that have an international element, also known as a "foreign element." This is the reason for the term "private" in the name. In contrast, public international law governs the relationships between states, international organizations, and other subjects of international law. The rules governing such relationships are not derived from domestic law, technically called "municipal law" in conflict of laws, but from international determinations such as agreements between states or their long-standing conduct impressed with opinio juris sive necessitatis.