A Primer on International Comity

The Supreme Court in Hilton v. Guyot (1895) famously defined international comity as “the recognition which one nation allows within its territory to the legislative, executive or judicial acts of another nation.” That definition is incomplete, however, as comity encompasses much more than the recognition of foreign acts. The Restatement (Fourth) of Foreign Relations Law defines international comity more broadly as “deference to foreign states that is not required by international law.”

Comity is not itself a doctrine, but rather a principle that informs a range of doctrines. This Primer describes different ways in which the principle of international comity manifests in procedural doctrines. After categorizing different types of comity-based doctrines, the Primer disambiguates different meanings of “comity abstention.”

Types of Comity Doctrines

It is helpful to distinguish comity doctrines by the type of foreign interest they are meant to accommodate. Doctrines of prescriptive comity recognize the interests of foreign lawmakers. Sovereign-party comity recognizes the interests of foreign governments as litigants. And doctrines of adjudicative comity recognize the interests of foreign courts.

It is also helpful to bear in mind that comity-based doctrines can require the affirmative recognition of foreign acts or decisions (what might be called “positive” comity doctrines) just as much as they might require restraint to make space for foreign interests (what might be called “negative” comity doctrines).

Prescriptive Comity

Positive doctrines of prescriptive comity include the Act of State doctrine, which directs U.S. courts to give effect to the decisions of foreign sovereigns within their own territory, and choice-of-law rules that lead U.S. courts to apply foreign law. As the U.S. Supreme Court put it in Bank of Augusta v. Earle (1839), “the laws of one [country], will, by the comity of nations, be recognized and executed in another.” Negative doctrines of prescriptive comity include the presumption against extraterritoriality and F. Hoffman-La Roche Ltd. v. Empagran S.A.’s (2004) principle of reasonableness, both of which are rules of statutory interpretation that limit the reach of federal statutes in part to avoid stepping on the toes of foreign lawmakers.

Sovereign-Party Comity

The Supreme Court has repeatedly recognized that foreign governments may appear as plaintiffs in U.S. courts as a matter of positive comity. Comity operates as a principle of restraint, however, in the field of immunities, shielding foreign states and government officials from suit in U.S. courts.

Adjudicative Comity

U.S. courts’ willingness to recognize and enforce foreign court judgments is an example of positive adjudicative comity. U.S. courts exercise restraint based on international comity when they limit discovery of evidence located abroad or avoid using antisuit injunctions.

There are also several negative adjudicative comity doctrines that permit judges to decline their jurisdiction out of respect for foreign courts. These include forum non conveniens, deference of foreign parallel proceedings, and coordination in cross-border bankruptcies. Some circuits have adopted negative adjudicative comity doctrines of prudential exhaustion and international comity abstention. The myriad options for deferring to foreign courts, along with inconsistent labeling, has led to some confusion in the courts. The remainder of this Primer attempts to disambiguate these different doctrines of negative adjudicative comity.

Disambiguating Abstention Doctrines Based on Comity

Even though there is no single doctrine of comity, courts sometimes refer to “the doctrine of international comity” or “comity abstention.” This misnomer has led to some confusion.

Typically, when courts speak of “comity abstention,” they have in mind deference to parallel proceedings in foreign courts or the closely related (but nonetheless distinct) question of whether to defer to foreign bankruptcy proceedings. Deference to foreign parallel proceedings requires the proceedings to be sufficiently parallel such that a judgment in one court could preclude a different judgment in the other court. Deference to foreign bankruptcy proceedings, in contrast, can encompass non-parallel proceedings because the goal is not to avoid preclusion problems, but rather to protect the originating court’s control over the disposition of the bankrupt’s estate.

Some circuits, however, have developed different understandings of comity-based abstention. In Ungaro-Benages v. Dresdner Bank AG (2004), the Eleventh Circuit distinguished between what it called “retrospective comity” and “prospective comity.” By “retrospective comity,” it meant deference to foreign parallel proceedings and the recognition and enforcement of foreign judgments. It defined “prospective comity” as allowing a court to say or dismiss a case “based on the interests of our government, the foreign government and the international community in resolving the dispute in a foreign forum.” Ungaro-Benages appears to be the only time that the Eleventh Circuit has applied this “prospective comity” abstention, and it has since suggested that Ungaro-Benages was sui generis in this respect. The Third Circuit has explicitly rejected the idea of “prospective comity.” The Ninth Circuit, however, has applied the Eleventh Circuit’s idea of “prospective comity” abstention in Mujica v. Airscan Inc. (2014) and Cooper v. Tokyo Elec. Power Co. (2020).

Meanwhile, the Second Circuit has invoked the idea of “international comity abstention” when interpreting the reach of federal statutes—a question of prescriptive, rather than adjudicative, comity. Reflecting this prescriptive comity context, the Second Circuit used conflict-of-laws considerations drawn from Timberlane to consider whether U.S. antitrust law should yield to Chinese antitrust law.

Finally, the Seventh Circuit has invoked a prudential exhaustion requirement for Foreign Sovereign Immunities Act (FSIA) cases, and the Ninth Circuit has suggested there might be a prudential exhaustion requirement for Alien Tort Statute (ATS) cases. There is no requirement under international law or U.S. law that private parties must exhaust claims locally before suing in the courts of another country. Indeed, the Seventh and Eleventh Circuits have rejected prudential exhaustion in ATS cases, while the Ninth and DC Circuits have rejected such a requirement in FSIA cases.

The area of negative adjudicative comity is in flux. The Supreme Court recently ducked the question of comity-based abstention in a pair of Holocaust restitution cases. Given the different approaches of the federal courts of appeals, it is important to be precise when researching or writing about “international comity abstention.”