Comity derives from the Latin comitas, courtesy, from cemis, friendly, courteous.
International law
The doctrine of international comity has been described variously "as a choice-of-law principle, a synonym for private international law, a rule of public international law, a moral obligation, expediency, courtesy, reciprocity, utility, or diplomacy. Authorities disagree as to whether comity is a rule of natural law, custom, treaty, or domestic law. Indeed, there is not even agreement that comity is a rule of law at all." Because the doctrine touches on many different principles, it is regarded as "one of the more confusing doctrines evoked in cases touching upon the interests of foreign states." The doctrine of international comity was created by a group of Dutch jurists in the late seventeenth century, most prominently Ulrich Huber. Huber and others sought a way to handle conflicts of law in a way that would reinforce the idea of Westphalian sovereignty. Huber wrote that comitas gentium required the application of foreign law in certain cases because sovereigns "so act by way of comity that rights acquired within the limits of a government retain their force everywhere so far as they do not cause prejudice to the powers or rights of such government or of their subjects." Huber "believed that comity was a principle of international law" but also that "the decision to apply foreign law itself was left up to the state as an act of free will." The idea of comity was introduced into English law by Lord Mansfield, a Scottish barrister and jurist. Mansfield viewed the application of comity as discretionary, with courts applying foreign law "except to the extent that it conflicted with principles of natural justice or public policy." Mansfield held in Somerset v Stewart, for example, that slavery was so morally odious that a British court would not recognize the property rights of an American slaveholder in his slave. In the United States, Louisiana attorney Samuel Livermore expressly rejected the comity doctrine as formulated by Mansfield and earlier writers, instead arguing that "courts were bound by international law to apply the same law that a foreign court would apply." This idea was rejected by Justice Joseph Story of the Supreme Court, who agreed with Mansfield and Huber in his Commentaries on the Conflict of Laws. Story's view, which ultimately prevailed, was that the consensual or voluntary application of comity doctrine would foster trust among states, "localize the effect of slavery," and reduce the risk of civil war. The U.S. Supreme Court's holding in Hilton v. Guyot that the enforcement of a foreign judgment was a matter of comity is viewed as the "classic" statement of comity in international law. The Court held in that case: In the UnitedStates, certain foreign defamation judgments are not recognized under the SPEECH Act, which supersedes the comity doctrine. The Actaims to stop "libel tourism."
In the United States, some states and territories recognize professional engineer licenses granted in a different jurisdiction, depending on the holder's education and experience. Rules differ significantly from jurisdiction to jurisdiction.
