Definition
Ex comitate is a Latin phrase meaning "out of comity" or "by courtesy." It describes an act done not as a matter of strict legal right or obligation, but as a voluntary concession extended by one sovereign, court, or legal system to another — or to a foreign party — in a spirit of mutual respect and goodwill. When a court acts ex comitate, it applies a foreign law, recognizes a foreign judgment, or accommodates a foreign interest not because it is compelled to do so, but because such recognition is consistent with the norms of comity among nations and legal systems.
The phrase is closely associated with the doctrine of comitas gentium (comity of nations), the principle that courts will give effect to foreign laws and judgments to the extent doing so does not conflict with the forum's own public policy or laws. Burrill cites Lord Mansfield's formulation — ex comitate et jure gentium, "by comity and the law of nations" — as the classical expression of the doctrine's dual grounding: one part voluntary courtesy, one part recognized international norm.
Common Confusion
Ex comitate is sometimes treated as synonymous with comity, but the phrase is more precise. Comity (comitas) names the doctrine or principle itself. Ex comitate describes the basis or justification for a particular act or concession — it answers the question "why is this court doing this?" when no domestic rule compels the result. A court applies foreign law ex comitate; the doctrine under which it does so is comity.
Why It Matters in Research
Researchers encounter ex comitate primarily in two contexts: conflict of laws and private international law. In older case reports and treatises, especially from the eighteenth and nineteenth centuries, the phrase appears as shorthand for the justification behind recognizing foreign marriages, enforcing foreign contracts, and giving effect to foreign judgments. When you see ex comitate in a historical source, it signals that the result reached was not legally required — it could have been withheld on public policy grounds without legal error.
The critical research trap is treating historical uses of ex comitate as equivalent to modern conflict-of-laws analysis. Courts in the nineteenth century had broad, nearly unreviewable discretion to extend or withhold comity. Modern choice-of-law frameworks (Restatement Second, interest analysis, and statutory conflicts rules) have partially replaced this discretionary courtesy with structured analysis. An argument that prevailed "ex comitate" in an 1830 English case does not map cleanly onto a modern multi-factor conflicts analysis.
The Burrill citation to 2 Kent's Commentaries 457 is a useful anchor point: Kent's treatment of comity as the basis for enforcing foreign laws is foundational American authority and widely cited in nineteenth-century American courts. Researchers working in pre-Erie federal common law or early American conflicts doctrine will find this lineage essential.
Note also that Lord Mansfield's pairing of ex comitate with jure gentium — the law of nations — reflects an older understanding in which comity and customary international law were not sharply distinguished. Modern international law treats these as distinct, and conflating them in contemporary analysis will create doctrinal confusion.
Historical Dictionary Support
All three sources agree on the core meaning: "out of comity or courtesy." Black's, Rapalje & Lawrence, and Burrill are virtually identical in their definitions, reflecting the phrase's stable, technical Latin usage. The phrase is not contested or ambiguous in the historical dictionaries.
Burrill adds the most substantive context, citing Kent and Lord Mansfield. The Mansfield formulation — ex comitate et jure gentium — is the more complete legal phrase and worth knowing separately. Black's treatment, characteristically brief, gives the translation without doctrinal development. None of the historical dictionaries engage with the tension between treating comity as pure discretion versus as a quasi-obligatory norm, a debate that runs through conflicts scholarship from Story through the twentieth century. Researchers should not expect dictionary entries from this period to resolve that debate; the phrase itself was used on both sides of it.
Encyclopedia Cross-Reference
Constitutional Law Encyclopedia: Ex parte Young — The Fiction That Permits Suits Against State Officers (constitutional_42) — relevant when exploring the boundary between judicial discretion and legal obligation, a theme intersecting comity doctrine in federalism contexts.