International tribunals sometimes also have a natural law of nations jurisdiction. For example, the ICJ has jurisdiction to decide cases ex aequo et bono (“according to what is just and good”) if the parties agree. And, most recently, the Agreement Establishing the Caribbean Court of Justice also explicitly has allowed the Caribbean Court to decide cases ex aequo et bono if the parties so agree.

Modern jurists generally attempt to avoid basing their decisions on natural law, and modern international jurists avoid basing their decisions on the necessary law of nations. Natural law approaches to jurisprudence generally are not in vogue. Most modern jurisprudence has replaced the deus ex machina of natural law with human choice. However, even some positive international law (such as treaties outlawing the slave trade and governing the conduct of warfare) explicitly recognizes natural law norms. For example, a 1786 U.S.-Prussia treaty explicitly recognized that prisoners of war were protected by “the law of nature or nations.” Other times, treaties use phrases such as “principles of natural justice,” “principles of Justice,” “principles of humanity,” and/or “dictates of public conscience,” to signify the natural law of nations status of the norms to which these phrases are attached. For example, Great Britain and France in the Treaty of Paris (1814) explicitly recognized that the slave trade violated “principles of natural justice.” The United States and Great Britain explicitly recognized in the Treaty of Ghent (1814) that the slave trade violated “principles of humanity and Justice.”