Duhaime's Law Dictionary

Modi Vivendi Definition:

Latin: limited force. A temporary and often limited interim agreement between states pending negotiation and ratification of a treaty.

Related Terms: Treaty, MOU, Memorandum of Understanding (MOU)

"As the term indicates, a modi vivendi is a temporary arrangement entered into for the purpose of regulating a matter of conflicting interests, until a more definite and permanent arrangement can be obtained in treaty form."

The Constitutional Law of the United States (1910).

Also modus vivendi.

The Encyclopedia of Public International Law:

"A modus vivendi is an arrangement of a temporary and provisional nature concluded between subjects of international law which gives rise to binding obligations to the parties.... It is an instrument of toleration looking towards a settlement.... Normally, it is used for provisional and interim arrangements which ultimately are to be replaced by a formal agreement of a more permanent and detailed character.... Usually a modus vivendi is agreed in a most informal way and does not require ratification."

The usual way to complete such a temporary agreement is by way of exchange of correspondence between diplomats.

In 1885, the Treaty of Washington expired between Canada and the United States. Rather than bring the international fisheries to a sudden halt and risk interruption of essential food stocks,  the parties agreed to a limited set of terms under which American fishing vessels might enter Canadian bays and harbours, pending the negotiation and ratification of a more extensive fishery treaty between the two states. This temporary stopgap agreement is called, and was then referred to as a modi vivendi.

As it turned out, no such treaty was ratified and so the modi vivendi was continued in effect indefinitely.

Another Canada-USA dispute resolved by modi vivendi was the border of Alaska. On October 20, 1899, an exchange of diplomatic notes confirmed the modi vivendi, a temporary solution, a provisional border, until such time as the proper boundary tribunal could finalize the border, which occurred in 1903; the treaty repealing and replacing the modi vivendi.


  • Bernhardt, Rudolf, Gen. Ed., Encyclopedia of Public International Law (Amsterdam: Elsevier, 1997), volume 3, pages 442-443.
  • Crandall, Samuel, Treaties: Their Making and Enforcement (Washington: John Byrne & Company, 1916), pages 112-113
  • Willoughby, W.W., The Constitutional Law of the United States, Volume 2 (New York: Baker Voorhis & Co., 1910), page 471, §201

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