International Law, Domestic Law, Private International Law, Model Laws and Non-Binding Principles

Five legal layers may appear in one transaction, but they do not perform the same function

A cross-border contract file may contain a treaty, domestic law, a private-international-law rule, a model law and non-binding principles. A common error is to place all of them in one basket called “international law.” Public international law primarily regulates relations of States and other entities it addresses. Domestic law operates within a national legal system. Private international law, within a given legal system, addresses questions such as applicable law or jurisdiction in cross-border private relationships. Model laws and non-binding principles reach practical effect through different routes.

Governing law is not the same as the chosen court or arbitration

The HCCH Principles on Choice of Law in International Commercial Contracts distinguish a choice-of-law agreement from choice-of-court and arbitration agreements, and they expressly describe themselves as non-binding. Governing law asks, in substance, which body of substantive law governs the contractual issues covered by the choice. A choice-of-court clause selects a judicial forum. An arbitration agreement selects an arbitral route within its terms. These choices may work together, but they are not synonyms.

A model law works through domestic enactment

The UNCITRAL Model Law on International Commercial Arbitration is a legislative model for States, not a treaty that operates directly by itself. A State may adopt it, modify it, or enact legislation influenced by it. The professional statement is therefore not “the Model Law governs the arbitration,” but “we need to verify the applicable domestic arbitration legislation and how it relates to the Model Law.” The distinction matters because the enacted domestic text supplies legal force within that system.

Non-binding principles can be useful without pretending they bind automatically

The UNIDROIT Principles of International Commercial Contracts are non-binding in themselves. They can still be valuable for drafting, as a contractual reference, or in interpretation where the legal framework permits. The central learning point is to distinguish “useful authoritative reference” from “applicable binding rule.” Professional reliability does not confuse a source’s quality with its legal force.

A treaty may affect a contract, but do not assume the route

The CISG is an example of a treaty providing a uniform regime for international sales within its scope, including contract formation, seller and buyer obligations, and remedies associated with breach. But “the transaction is international” is not enough. Verify the Convention’s scope, State status where that status is part of the route to applicability, and any relevant choices or exclusions. Do not turn this example into a rule for every international contract.