Opinio Juris

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Opinio Juris

Definition

The “actual practice” or customs of States. It comprises customary international law. For acts to be considered opinio juris, they must amount to a settled practice, and must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is obligatory despite the lack of a rule of law requiring it.

Related rules

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— Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965

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— Flores v. Southern Peru Copper Corp.

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— Interlocutory Decision on the Applicable Law: Terrorism, Conspiracy, Homicide, Perpetration, Cumulative Charging

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— In the Name of the Cambodian People and the United Nations and Pursuant to the Law on the Establishment of the Extraordinary Chambers in the Courts of Cambodia for the Prosecution of Crimes Committed During the Period of Democratic Kampuchea

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— Legality of the Threat or Use of Nuclear Weapons

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