Originally from Anti-suit Injunctions in International Arbitration

A.   International Comity

As a component of private international procedural law and international arbitration, anti-suit injunctions have links with many crucial concepts in the same fields. One of these important concepts is called international comity. This principle dates back to middle ages,  and has a significant impact on whether courts will order or uphold anti-suit injunctions. The analysis of this close relationship is essential because as can be seen from the discussions below, courts that reject anti-suit injunctions or are inclined to a very narrow interpretation of these remedies primarily base their approaches on the principle of international comity.

International comity does not have a uniform definition, yet it has played a significant role in private international law.  This principle refers to the amity that has arisen from the “necessities of interstate friendships” without specifically relying on any written agreement among countries.  International comity requires a national court to trust in competence and success of foreign courts to adjudicate a dispute properly.  The US Supreme Court defines international comity as follows:

        The recognition which one nation allows within its territory to the legislative, executive or judicial acts of another nation, having due regard both to international duty
         and convenience and to the rights of its own citizens or of other persons who are under the protection of its laws. 

Some definitions are emphasizing aspects that are more relative in terms of anti-suit injunctions.  International comity can also be defined as a doctrine, which requires that “the foreign court should be entrusted with the authority to independently apply its own law of evidence in the process of judging.”  Thus, in a literal sense an anti-suit injunction should be considered inappropriate vis-à-vis international comity because it enjoins parties and suggests a lack of faith in the foreign forum.