Originally from American Review of International Arbitration, Vol. 29 No. 3

Comity among nations is a notoriously ambiguous concept, classically defined as being “neither a matter of absolute obligation …nor of mere courtesy and good will.”

Derived from territorial sovereignty, comity was advocated as a framework to address the earliest conflict of laws scenarios, countervailing the parochial inclination of a sovereign to apply its own law within its borders to the exclusion of all other law. As now applied, it is generally used to justify a court’s decision to show deference to a foreign proceeding and a foreign decision maker.  Therefore, comity is a vague idea that evades precise definition—something that has frustrated certain commentators, especially in England, who view international comity as a matter of foreign relations ill-suited to the judicial role

Comity is also a source principle, giving rise to more precise doctrines with defined elements and consequences, such as lis pendens, res judicata or issue estoppel.  Further, comity limits the availability of anti-suit injunctions.   As rules aimed at preserving the integrity of pending and prior proceedings, and in so doing, avoiding chaos, these related doctrines and remedies promote comity interests by requiring a court to defer to the jurisdiction of foreign legal orders.  Yet, protecting comity interests through the application of such rules is decidedly different from empowering courts to resort to comity as such.  When a court views a given topic through the prism of comity, it retains flexibility, whereas when a court applies one of the rules derived from comity, it is confined in its decision by the technicality of these rules.

Paradoxically, when legal systems specifically empower courts to resolve questions of overlapping jurisdiction using comity—which mostly occurs in common law systems, they may weaken respect for foreign legal orders.  When placed in the hands of an interventionist judge, a flexible principle like comity can be used to expand a court’s discretion to act extraterritorially rather than limit it.  As such, the flexibility of comity as a principle of judicial decision-making makes it somewhat of an “Orwellian” concept, working to undermine the very interests for which it stands.