A Primer on Foreign Official Immunity

Foreign official immunity refers to rules of international and domestic law that shield foreign officials from suit and from criminal prosecution. These rules are related to the rules of foreign sovereign immunity, codified in the U.S. Foreign Sovereign Immunities Act (FSIA), but they differ from those rules in many respects. Rules of foreign official immunity generally fall into three categories: (1) diplomatic and consular immunity; (2) head of state immunity; and (3) conduct-based immunity.

The immunities of diplomatic and consular officials are codified in two widely adopted treaties, the Vienna Convention on Diplomatic Relations (VCDR) and the Vienna Convention on Consular Relations (VCCR). Head of state immunity and conduct-based immunity are not codified in treaties and are instead governed by customary international law.

Within the U.S. legal system, the VCDR and VCCR are both considered self-executing treaties. Nevertheless, diplomatic immunity is implemented through the Diplomatic Relations Act, whereas the applies directly without implementing legislation. By contrast, federal common law governs head of state immunity and conduct-based immunity. In Samantar v. Yousuf (2010), the U.S. Supreme Court rejected the argument that the Foreign Sovereign Immunities Act applies to foreign officials, holding instead that their immunities are governed by common law. In the wake of Samantar, the executive branch has claimed broad authority to articulate the rules of foreign official immunity and to make binding determinations of immunity in particular cases, although the executive’s authority is disputed.

Diplomatic and Consular Immunity

Under Article 31 of the VCDR, diplomats enjoy absolute immunity from the criminal jurisdiction of the receiving state and nearly absolute immunity from civil and administrative proceedings. Article 37 extends the same immunities to members of a diplomat’s household and to the diplomatic mission’s administrative and technical staff. These immunities end when their diplomatic functions end and they leave the receiving state. But under Article 39(2), a former diplomat continues to enjoy immunity “with respect to acts performed by such a person in the exercise of his functions as a member of the mission.” Article 32 allows a sending state to waive the immunity of its diplomats.

The Diplomatic Relations Act extends diplomatic immunity to diplomats from countries that are not parties to the VCDR. Courts have held that the State Department’s certification of a person’s diplomatic status is conclusive.

In contrast to diplomats, consular officials do not have absolute immunity. Under Article 43 of the VCCR, they enjoy immunity only for acts performed in the exercise of their consular functions. As with diplomats, Article 45 allows a sending state to waive the immunity of its consular officials.

Head of State Immunity

In Case Concerning the Arrest Warrant of 11 April 2000 (Dem. Rep. Congo v. Belg.) (2002), the International Court of Justice (ICJ) noted that, under customary international law, sitting heads of state, heads of government, and foreign ministers are absolutely immune from suit in the courts of other states during their terms of office. Head of state immunity is a status-based immunity that attaches because of these officials’ positions, in order to protect the effective performance of their functions. Head of state immunity is absolute in the sense that it applies to all acts, including acts taken in a private capacity and acts performed before the official assumed office. Such absolute immunity lasts, however, only during the official’s tenure in office. Former heads of state, heads of government, and foreign ministers are entitled only to conduct-based immunity (discussed below) for acts taken in an official capacity.

As Samantar made clear, federal common law governs head of state immunity in the United States. The State Department routinely files suggestions of immunity for foreign heads of state, heads of government, and foreign ministers, and U.S. courts treat these suggestions as conclusive. U.S. courts also apply federal common law and dismiss suits against these officials in those rare case when the executive branch remains silent.

Conduct-Based Immunity

A foreign official who is not entitled to diplomatic, consular, or head of state immunity is still immune from suits based on acts taken in an official capacity. This immunity is called conduct-based immunity because it depends on the nature of the conduct rather than on the status of the official. The ICJ alluded briefly to conduct-based immunity under customary international law in the Arrest Warrant Case (¶ 61), and the U.S. Supreme Court recognized such immunity in Samantar.

Whether an act is taken in an official capacity for purposes of conduct-based immunity is a separate question from whether the act was performed under color of foreign law or is attributable to a foreign state. An act may be authorized by a foreign government and attributable to it, but still not be entitled to conduct-based immunity. The classic example is espionage. For example, the United States did not claim immunity for Francis Gary Powers when his spy plane was shot down over the Soviet Union. It is generally accepted today that sabotage, kidnapping, and political assassination are also not entitled to conduct-based immunity.

More controversial have been violations of universally accepted prohibitions like torture, genocide, war crimes, and crimes against humanity. State practice on granting conduct-based immunity for such violations has been mixed, as discussed at pp. 705-07 of this article. Some scholars have argued that the lack of consistent practice granting immunity for such violations means that no such immunity exists. Other scholars have argued that the lack of consistent practice shows that international law recognizes no exception to immunity for such violations.

The Role of the Executive Branch

After Samantar, the executive branch claimed broad authority to articulate rules of foreign official immunity and to make binding determinations of immunity in particular cases. In a 2020 amicus brief filed with the U.S. Supreme Court, the Department of Justice stated:

Under this Court’s decisions, the principles recognized by the Executive Branch governing foreign-official immunity are to be followed by the courts. That is true not only in cases in which the Executive files a suggestion of immunity, but also in cases in which courts must decide for themselves whether a foreign official is immune from suit.

The executive branch bases its authority on two Supreme Court decisions from the 1940s, Ex Parte Peru (1943) and Republic of Mexico v. Hoffman (1945), deferring to State Department on questions of foreign sovereign immunity. Although the State Department’s role with respect to foreign sovereign immunity has been superseded by the FSIA, the executive branch argues that U.S. courts must still defer to the executive on questions of foreign official immunity.

With respect to determinations in individual cases, U.S. courts do treat the State Department’s suggestions of head of state immunity as conclusive.  Pursuant to the Supreme Court’s decision in Zivotofsky v. Kerry, the executive has the exclusive constitutional authority to decide whom the United States recognizes as foreign heads of state, heads of government, and foreign ministers.  The executive does not have the power to dictate the domestic legal consequences of recognition, but with respect to head of state immunity, the law (both international and domestic) is clear. As Ingrid Wuerth has noted, head of state immunity “follows almost always as a matter of course from these determinations.”

By contrast, courts are divided on whether executive determinations of conduct-based immunity are conclusive. The Second Circuit has held that such determinations are binding on courts, whereas the Fourth Circuit has held that they are “not controlling” but carry “substantial weight.” As the Fourth Circuit explained on remand in the Samantar case, “[u]nlike head-of-state immunity and other status-based immunities, there is no equivalent constitutional basis suggesting that the views of the Executive Branch control questions of [conduct-based] immunity.”

Although the executive branch claims that what it says about the rules of foreign official immunity binds U.S. courts even in cases where it does not make an individual determination, it is difficult to see where such lawmaking authority comes from. Absent a delegation from Congress, the executive generally lacks lawmaking power, as the Supreme Court has repeatedly emphasized. Wuerth has pointed out that the status of foreign official immunity as federal common law strongly suggests that courts rather than the executive must be responsible for making its rules. And, as Chimène Keitner and I have observed, “[i]n practice, courts have looked to sources other than the executive branch for principles to apply.”

Procedural Aspects

Some of the ways that foreign official immunity diverges from foreign sovereign immunity in the United States are found in its procedural aspects. Because the Supreme Court held in Samantar that the FSIA does not apply to foreign officials, the FSIA may not be used to establish subject matter jurisdiction, personal jurisdiction, or to serve the defendant.

Following a path worn by cases applying the FSIA, however, most courts have treated foreign official immunity as a question of subject matter jurisdiction, notwithstanding the fact that the FSIA does not apply. This creates tensions with other rules of U.S. law, including the principle that only Congress is supposed to create rules of subject matter jurisdiction. Keitner and I have suggested that foreign official immunity should be treated instead as a an affirmative defense, with the burden of proof on the foreign official, just like the qualified immunity of U.S. officials.

But because foreign official immunity is immunity from suit, not just liability, it must be decided at the threshold of a case. Limited discovery may be permitted to resolve the question of foreign official immunity, just as it is to resolve questions of foreign sovereign immunity. Courts may alternatively dismiss suits against foreign officials on other threshold grounds like lack of personal or subject matter jurisdiction, forum non conveniens, or (if foreign official immunity is considered an affirmative defense) failure to state a claim. Finally, the denial of foreign official immunity must be immediately appealable, as U.S. courts have held.