Private international law, also called conflict of laws in common-law systems, governs private (non-state) legal relationships that cross borders. Unlike public international law, which regulates relations between states, private international law deals with disputes between individuals, companies, or other private parties when more than one legal system could plausibly apply — for example, a marriage contracted in one country and dissolved in another, a contract between firms headquartered on different continents, or a cross-border tort.
The field traditionally addresses three core questions:
- Jurisdiction: Which country's courts have authority to hear the dispute?
- Choice of law: Which legal system's substantive rules govern the merits?
- Recognition and enforcement: Will a judgment rendered in one state be recognised and enforced in another?
Sources are a mix of domestic statutes, bilateral treaties, and multilateral instruments. The Hague Conference on Private International Law (HCCH), founded in 1893 and headquartered in The Hague, is the principal global body producing harmonising conventions. Well-known HCCH instruments include the 1980 Convention on the Civil Aspects of International Child Abduction, the 1961 Apostille Convention, and the 2005 Choice of Court Convention. Within the European Union, regulations such as Rome I (contractual obligations, Regulation 593/2008), Rome II (non-contractual obligations, Regulation 864/2007), and the Brussels I Recast (Regulation 1215/2012) unify these rules among member states.
Arbitration occupies a closely related space: the 1958 New York Convention on the Recognition and Enforcement of Foreign Arbitral Awards is one of the most widely ratified commercial treaties in the world.
For MUN delegates and IR researchers, private international law is relevant whenever debate turns to cross-border family matters, transnational commerce, digital platforms, or extraterritorial application of national statutes. It is distinct from — though sometimes overlaps with — public international law on topics such as human rights litigation and sovereign immunity.
Example
In the 2020 UK Supreme Court case *Vedanta Resources v. Lungowe*, Zambian villagers were permitted to sue a UK-domiciled parent company in English courts over pollution in Zambia, illustrating how private international law rules on jurisdiction shape transnational liability claims.
Frequently asked questions
Public international law governs relations between states and international organisations; private international law governs cross-border disputes between private parties and determines which national legal system applies.
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