In Vis, the law that governs the hypothetical contract (the "substantive" law) is always the United Nations Convention on the International Sale of Goods (CISG), aka the Vienna Convention. The CISG was a treaty signed in Vienna in 1980 (hence the name) and came into force in 1988 after being ratified by 10 countries. The Vis moot was started to promote the CISG (and not just wiener schnitzel).
The CISG was written by the United Nations Commission on International Trade Law (UNCITRAL) in the 1970s though it makes no mention of disco. It was based on a 1964 treaty, the Uniform Laws on the International Sale of Goods (ULIS). As with many treaties, CISG relied on compromise, especially between the common law and civil law countries and between the West and the Soviet bloc countries. Some of the fine points of CISG law turn on reading the drafting history and compromises between the delegates.
The CISG has been ratified by at least 70 countries that together account for three-quarters of world trade. This does not mean that three-quarters of international contracts are governed by the CISG. Countries may adopt the CISG with their own reservations, especially regarding writing requirements. To avoid this complication and any other peculiar features of national laws, the countries of the parties in the Vis Problem are hypothetical, usually some combination of Mediterraneo, Equatoriana, and Oceania. The dispute always takes place in Vindobona, Danubia (the old Roman name for Vienna).
Private parties are also free to adopt modified provisions of the CISG or other governing laws. One notable alternative or supplement to the CISG that private parties may adopt and, in a sense, the successor to the CISG, is the UNIDROIT Principles of International Commercial Contracts, written in 1994 then revised and enlarged in 2004. UNIDROIT, which somehow stands for the International Institute for the Unification of Private Law, is an intergovernmental organization created to harmonize international commercial law. While not a treaty, the UNIDROIT Principles perform a similar role to the CISG in stating rules to govern international commercial contracts. In the US, the CISG is comparable to the Uniform Commercial Code whereas the UNIDROIT Principles are like the Restatements of Law by the American Law Institute. The UNIDROIT Principles cover some issues that are inadequately or not addressed at all in the CISG. As such, it provides persuasive, though not binding, authority for a moot based on the CISG.Back to top