Introduction

This guide provides a brief definitional overview of public international law, private international law, and foreign law. If you would like a more in-depth look at international law, have a look at our related guide.

If you have questions, please feel free to contact the Wolff Library reference desk at 202-662-4195 or by email: intlref@law.georgetown.edu. You may also submit your question via this online form.

Public International Law

Public international law governs the relationships between national governments, the relationships between intergovernmental organizations, and the relationships between national governments and intergovernmental organizations. It regulates governments and intergovernmental organizations across national boundaries.

The sources of international law are based on Article 38 of the ICJ Statute:

• International conventions (treaties);
• Customary law (general practice of states and intergovernmental organizations that are legally binding and generally recognized by all states);
• General principles of law; and
• Judicial decisions and the teachings of the most highly qualified publicists of the various nations.

Private International Law

Private international law governs the choice of law to apply when there are conflicts in the municipal law of different countries related to private transactions between those countries. Often it is known as conflict of laws. National laws are the primary sources of private international law. However, private international law is also embodied in public international law sources, especially treaties (for example, the Hague Conventions on Private International Law). Private international law deals with topics such as contracts, marriage and divorce, jurisdiction, recognition of judgments, child adoption and abduction, and many other areas.

Foreign Law

Foreign law is essentially national or subnational law. It defines the role of governments to the people they govern and controls relationships between people. It may regulate foreign persons and entities, but it does not have effect outside the boundaries of a nation. Foreign law is embodied in constitutions, statutes, regulations, and court decisions. Constitutions, statutes and regulations are primary sources of law for all jurisdictions. Courts decisions are also primary sources of law in common law jurisdictions, but are considered secondary sources of law in civil law jurisdictions.

For a quick look at the major legal systems (civil law, common law, etc.), see World Legal Systems.

For more detailed information on foreign law, see our Foreign and Comparative Law guide.