Definition
Comity (recorded here as OCOMITY) refers to the principle of mutual respect and deference that one sovereign, court, or jurisdiction extends to the laws, judgments, and official acts of another. It is not a rule of law and confers no enforceable right. It is, instead, a disposition — a willingness to recognize and give effect to foreign legal authority as a matter of courtesy, goodwill, and practical necessity, not obligation.
Comity operates at two levels:
1. International comity: The recognition by one nation of another nation's laws, judicial decisions, and governmental acts within its own territory. It is grounded in mutual convenience and the practical reality that nations benefit from reciprocal deference. A nation may decline to extend comity when doing so would violate its own public policy, prejudice its citizens, or conflict with its statutes.
2. Domestic (interstate) comity: The deference one U.S. state extends to the laws and judgments of a sister state. This overlaps with, but is not identical to, the Full Faith and Credit obligations imposed by the U.S. Constitution. Where Full Faith and Credit compels recognition, comity fills the space where it does not.
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Common Confusion
Comity is frequently confused with Full Faith and Credit. They are related but distinct. Full Faith and Credit (U.S. Const. Art. IV, § 1) is a constitutional mandate — states must recognize the judgments of sister states. Comity is discretionary — a court may choose to recognize a foreign judgment or law but is not constitutionally required to do so in every context. When a researcher encounters comity arguments in interstate or international litigation, the threshold question is always whether a mandatory rule (Full Faith and Credit, treaty obligation, or statute) controls, or whether the court is being invited to exercise discretion.
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Why It Matters in Research
The Black's 2nd Ed. entry for this term is incomplete as supplied — the definition is cut off mid-sentence at "inadmisible when it is," omitting the conditions under which comity is withheld. Researchers relying on this truncated source will miss the essential limiting principle. Later editions of Black's and secondary treatise literature supply the complete formulation: comity is inadmissible when it prejudices the rights of the forum state's own citizens or conflicts with its laws and policy.
Researchers tracing comity arguments in 19th- and early 20th-century American cases should be alert to the influence of Justice Joseph Story's Commentaries on the Conflict of Laws (1834), which shaped American courts' understanding of comity for generations. The term appears in conflict-of-laws litigation, enforcement-of-judgments proceedings, abstention doctrine cases in federal courts, and sovereign immunity contexts.
In federal court research, comity underlies several abstention doctrines (Younger abstention, Pullman abstention) even when the word "comity" does not appear in the opinion's headnotes. Searching only on the term itself will undercount relevant authority.
In international law research, comity is the bridge concept between hard treaty obligations and the gap-filling practice of states. Its discretionary character means that judicial treatment of comity is highly fact- and policy-specific, making doctrinal synthesis across jurisdictions difficult.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) defines the term as: "Courtesy; complaisance; respect; a willingness to grant a privilege, not as a matter of right, but out of deference and good will." The entry further characterizes comity of nations as "the most appropriate phrase to express the true foundation and extent of the obligation of the laws of one nation within the territories of another," derived "altogether from the voluntary consent of the latter." The supplied text is truncated and does not record the conditions under which comity is withheld.
This definition is consistent with the classical formulation. The emphasis on voluntary consent and the explicit rejection of comity as a matter of right are the load-bearing elements of the concept and have remained stable across editions and across American and English legal dictionaries. What historical dictionaries tend to underemphasize is the domestic dimension — comity among states within a federal system — which became increasingly important in American jurisprudence as federal-state and interstate conflicts multiplied through the 20th century.
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Jurisdictional Note
In U.S. federal courts, comity toward state courts is a structural principle with constitutional overtones, informing abstention doctrines that limit federal intervention in pending state proceedings. In private international law, comity operates differently across common law and civil law systems; civil law jurisdictions more often encode recognition rules by statute, reducing the discretionary space that comity occupies in common law systems.
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