A.  Notion

1  The terms ‘extraterritoriality’ and ‘extraterritorial jurisdiction’ refer to the competence of a State to make, apply and enforce rules of conduct in respect of persons, property or events beyond its territory. Such competence may be exercised by way of prescription, adjudication or enforcement. Prescriptive jurisdiction refers to a State’s authority to lay down legal norms. Adjudicative jurisdiction refers to a State’s authority to decide competing claims. Enforcement jurisdiction refers to a State’s authority to ensure compliance with its laws. As will be seen below, these distinctions are important because some methods of exercising extraterritorial jurisdiction of States are more likely to conflict with the competence of other States and therefore more likely to raise questions as to their compatibility with international law.

2  In the absence of a universally accepted definition, extraterritoriality is an elusive concept that may include a wide variety of practices. Depending on the definition chosen it may encompass, for example, the adoption and adjudication of anti-trust legislation (see also Antitrust or Competition Law, International), the regulation of the export of toxic waste, the bringing to justice of terrorists and drug-traffickers, and the implementation of economic sanctions. The wide variety of matters covered by the concept makes it difficult to draw general conclusions about its status under international law.

B.  History and Context

3  The traditional view is that the exercise of extraterritorial jurisdiction is permissible in exceptional circumstances only. States enjoy full sovereign powers within their territories and any exercise of jurisdiction on another State’s territory obviously risks infringing that State’s sovereignty. In the Island of Palmas Case (Netherlands v United States of America) (Palmas Island Arbitration), arbitrator Max Huber famously identified the ‘principle of the exclusive competence of the State in regard to its own territory’ as the ‘point of departure in settling most questions that concern international relations’ (at 838).

4  However, in the age of globalization Huber’s presumption against extraterritoriality has become less self-evident. As Judges Higgins, Kooijmans, and Buergenthal pointed out in their joint individual opinion in the Arrest Warrant Case (Democratic Republic of the Congo v Belgium): ‘The movement is towards bases of jurisdiction other than territoriality’ (at 76). States increasingly perceive the need to protect both their own interests and the interests of the international community in respect of conduct occurring beyond their borders. Developments driving this trend include increases in a) international travel and migration of persons; b) international trade and investment by multinational enterprises (see also Investments, International Protection); c) peacekeeping, peacemaking and other military enforcement action; d) environmental degradation and climate change (see also Environment, International Protection; Climate, International Protection); e) transnational organized crime and international terrorism; and f) legal and illegal uses of the internet. In the past the exercise of extraterritorial jurisdiction raised questions especially under international economic law and international criminal law. As a result of globalization it increasingly raises questions under other branches of international law as well, including international human rights law and international environmental law.

5  States differ considerably in their general approach towards extraterritorial jurisdiction. For example, although they share a common legal tradition, the United Kingdom (‘UK’) and the United States of America (‘US’) have often found themselves at different ends of the spectrum. The UK has long been a committed supporter of Huber’s restrictive attitude. The US, on the other hand, has particularly since World War II frequently seen fit to exercise extraterritorial jurisdiction by way both of prescription, adjudication and enforcement.

C.  Lawfulness

6  A State’s attempt to make, apply and enforce rules of conduct in respect of events outside its own territory may bring it into direct conflict with the territorial State’s attempt to do the same. The exercise of extraterritorial jurisdiction may therefore clash with the prohibition of interference in another State’s internal affairs or violate its right to territorial integrity and political independence. Due to the scarcity of relevant international case law, the general principles governing the conflict are still derived from the 1927 judgment of the Permanent Court of International Justice (PCIJ) in The Case of the SS ‘Lotus’ (France v Turkey) (Lotus, The). The Lotus Case revolved around the question whether a Turkish court could try a French national for criminal responsibility for a collision on the high seas between a French and a Turkish vessel resulting in the deaths of Turkish nationals on board the Turkish vessel. The Lotus Case is rather peculiar because of its subject-matter (a maritime accident on the high seas), the narrow majority by which it was adopted (casting vote of the President of the PCIJ) and the long time which has passed since it was adopted. Nevertheless, the judgment produced three principles that still govern the lawfulness of the exercise of extraterritorial jurisdiction (Lotus Case 18–19).

7  The first principle is that whether a State may lawfully exercise extraterritorial jurisdiction is a matter of international law. This is not controversial. It makes sense that States cannot unilaterally decide the limits of their own competence to exercise jurisdiction beyond their territories.

8  The second principle is that, as a general rule, international law prohibits the exercise of extraterritorial enforcement jurisdiction unless this is specifically permitted:

Note that this principle refers specifically to the exercise of enforcement jurisdiction and not to prescriptive or adjudicative jurisdiction. The principle is again not controversial and reflects the law as it stands.

9  The third principle is that the exercise of extraterritorial prescriptive and adjudicative jurisdictions is permitted only if there is a sufficient connection between the State exercising it and the extraterritorial event. Unfortunately the PCIJ states this principle in more ambiguous terms:

While it is perfectly understandable that the PCIJ wished to point out that the exercise of extraterritorial jurisdiction by way of prescription and adjudication is less objectionable than by way of enforcement, State practice does not support the view that the exercise of any form of prescriptive and adjudicative jurisdiction beyond a State’s borders is permitted as long as there is no specific rule of international law prohibiting it.

10  What is a ‘sufficient connection’ may be established initially with reference to certain general principles of jurisdiction (see also Criminal Jurisdiction of States under International Law). However, it should immediately be pointed out that these principles must be employed with great caution. The suggestion sometimes made is that any exercise of extraterritorial jurisdiction that is in conformity with one of these principles is automatically lawful under international law. This would be far too simplistic. The principles differ considerably in the extent to which they offer a legitimate basis for exercising jurisdiction.

11  The ‘active nationality principle’ refers to the (criminal) jurisdiction a State may exercise in respect of its own nationals abroad, including not only natural persons but also companies, ships and aircraft that have its nationality. This principle dates back to pre-Westphalian times and is therefore well-established. Examples of the modern application of the active nationality principle in multilateral treaties may be found in Art. 5 (1) (b) Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment of 1984 ([adopted 10 December 1984, entered into force 26 June 1987] 1465 UNTS 112; ‘CAT’) and Art. 7 (1) (a) International Convention for the Suppression of the Financing of Terrorism ([signed 9 December 1999, entered into force 10 April 2002] 2178 UNTS 197). The principle is also increasingly being employed by States to criminalize certain serious offences such as acts of paedophilia and human trafficking when committed by their own nationals abroad.

12  The ‘passive personality principle’ refers to the (criminal) jurisdiction a State may exercise in respect of conduct abroad which injures its own nationals. This basis for jurisdiction has long been considered controversial. However, in their joint separate opinion in the Arrest Warrant Case Judges Higgins, Kooijmans, and Buergenthal asserted that the principle ‘today meets with relatively little opposition, at least so far as a particular category of offences is concerned’ (at 77). What the three judges apparently had in mind is that the passive personality principle is increasingly being included in treaties intended to combat crimes under international law. Examples are Art. 5 (1) (b) CAT and Art. 6 (2) (a) International Convention for the Suppression of Terrorist Bombings ([signed 15 December 1997, entered into force 23 May 2001] (2149 UNTS 256). Interestingly, these provisions also provide a legal basis for the exercise of jurisdiction in respect of nationals of non-States Parties to the treaties in question. This indicates that the provisions are regarded as codifications of customary international law.

13  The ‘protective principle’ refers to the (criminal) jurisdiction a State may exercise in respect of persons, property or events abroad that may constitute a threat to its essential interests, including acts against national security, such as coups d’état, terrorist acts, counterfeiting currency and forging passports (International Criminal Jurisdiction, Protective Principle). Although the validity of this principle is not contested it provides a rather uncertain basis for the exercise of extraterritorial jurisdiction because the conditions under which it may be relied upon are ill-defined.

14  The ‘universality principle’ refers to the (criminal) jurisdiction a State may or is required to exercise in respect of certain serious crimes irrespective of the location of the crime and irrespective of the nationality of the perpetrator or the victim. The universality principle is applicable only to certain crimes under international law that have been made subject to universal jurisdiction either by a multilateral treaty or under customary international law, such as genocide, war crimes, crimes against humanity, and torture (Torture, Prohibition of). Unlike the protective principle the interests protected are not those of the prosecuting State but those of the international community as a whole. Perhaps for this reason the universality principle long remained a theoretical concept only. It was contained in widely ratified treaties—with respect to war crimes, for example, in Art. 49 Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field of 1949 (75 UNTS 31), Art. 50 Geneva Convention for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea of 1949 (75 UNTS 85), Art. 129 Geneva Convention relative to the Treatment of Prisoners of War of 1949 (75 UNTS 135) and Art. 146 Geneva Convention relative to the Protection of Civilian Persons in Time of War of 1949 (75 UNTS 287)—but not applied in practice. The emergence of international criminal tribunals, demonstrating that war crimes could be successfully prosecuted, and sustained campaigning by human rights groups has changed this state of affairs.

15  The ‘effects principle’ refers to the (civil) jurisdiction a State may exercise when foreign conduct produces substantial effects on its territory. In the United States v Aluminum Co of America (148 F 2d 416 [2^nd Cir 1945]) the US Federal Court observed: ‘it is settled law…that any state may impose liabilities, even upon persons not within its allegiance, for conduct outside its borders that has consequences within its borders which the state reprehends’ (at 443). Unlike the principles referred to above, the effects principle tends to be invoked in support of the exercise of extraterritorial jurisdiction in commercial rather than criminal cases. In spite of its US origin, the effects principle has also been relied upon by European States, such as Germany and France, and by the European Union (‘EU’) as a justification for their exercise of extraterritorial jurisdiction in anti-trust cases, for example with regard to Amazon, Apple, Facebook, and Google. There is, however, no universal agreement on the precise contents of the effects principle.

16  In other words, these five principles do not provide a coherent and straightforward model by which it can be authoritatively determined whether in a given situation the exercise of extraterritorial jurisdiction by way of prescription or adjudication is lawful or not. There is also considerable overlap between them. In practice States pick and choose from the principles in order to justify the policies they wish to adopt. The US, for example, favours application of the effects principle, because this generally supports its commercial policies. But it is very critical of the universality principle, because it may be relied upon as a legal basis for bringing US officials and members of its armed forces to justice before foreign courts. For the same reason, some African States have also adopted a critical attitude towards the universality principle.

D.  Prescriptive and Adjudicative Jurisdiction

E.  Enforcement Jurisdiction

23  Extraterritorial enforcement may range from conduct on the territory of another State authorized by that State (such as police investigations, the serving of court papers, discovery and the enforcement of judgments), to conduct without such authorization (such as abductions and assassinations; see also Abduction, Transboundary). Unlike the international legal regime applicable to extraterritorial prescription and adjudication, the legal regime applicable to extraterritorial enforcement is quite straightforward. Without the consent of the host State such conduct is absolutely unlawful because it violates that State’s right to respect for its territorial integrity.

24  Consent to extraterritorial enforcement may be granted through bilateral agreements or through multilateral instruments, such as the 1984 Inter-American Convention on Jurisdiction in the International Sphere for Extraterritorial Validity of Foreign Judgments ([done 24 May 1984, entered into force 24 December 2004] (1985) 24 ILM 468) or EU Council Regulation (EC) No 44/2001 of 22 December 2000 on the Jurisdiction and the Recognition and Enforcement of Judgments in Civil and Commercial Matters ([2001] OJ L12/1, 23). In practice, on-the-spot extraterritorial police investigations are often conducted without a formal agreement between the States involved on the basis of informal contacts between the police forces (see also Transboundary Cooperation between Local or Regional Authorities).

25  An example of extraterritorial enforcement without consent of the host State is the abduction from foreign territory of persons suspected of having committed criminal offences with the purpose of bringing them to justice in the abductors’ own State. Thus, Adolf Eichmann was abducted by Israeli agents from the Argentine Republic in 1960 (Eichmann Case); Israeli nuclear technician Mordechai Vanunu was abducted by Israeli agents from the Italian Republic in 1986; Panamanian General Manuel Noriega was abducted by US armed forces from the Republic of Panama in 1989; and Mexican doctor Humberto Alvarez-Machain was abducted by US agents from the United Mexican States in 1990. Such transfrontier kidnappings without the consent of the territorial State raise the question whether the violation of its territorial integrity and the violation of the human rights of the victim should not present an obstacle to his trial. However, in each of the above cases the domestic courts rejected defence arguments along these lines and relied on the doctrine male captus bene detentus. This doctrine has been discredited in most States, but in the US—where it is referred to as the Ker–Frisbie doctrine—the courts still adhere to it.

26  Another example of extraterritorial enforcement action without consent of the host State is the cross-border assassination of non-combatants suspected of having committed criminal offences (see also Combatants). Such targeted killings (Targeted Killing) may be carried out through precision weapons launched from the air including from drones. This technique was first practised by Israel in the Occupied Territories and by the US in various places around the world but has since also been adopted by other States and armed groups (see also Israel, Occupied Territories). The first reported case occurred in 2002. The New York Times reported that six suspected terrorists driving a Jeep in a remote area in Yemen had been killed by a missile launched from an unmanned Predator drone operated by the US Central Intelligence Agency (J Risen and J Miller ‘Threats and Responses: Hunt for Suspects; CIA is Reported to Kill a Leader of Qaeda in Yemen’ New York Times [5 November 2002]). In 1985, French secret agents sunk the Greenpeace vessel Rainbow Warrior in New Zealand killing one of the people on board (Rainbow Warrior, The). But unlike the US and Israel, the French government subsequently apologized for the action and agreed to pay compensation to both New Zealand and Greenpeace, thus acknowledging that it had acted contrary to international law.

F.  Countermeasures

27  The exercise of extraterritorial jurisdiction contrary to international law will not be recognized by other States. It may also give rise to State responsibility and countermeasures by injured States. A peculiar type of countermeasure against the unlawful exercise of extraterritorial jurisdiction consists of so called ‘blocking statutes’. Blocking statutes attempt to prevent the implementation of extraterritorial measures by prohibiting compliance with them. They may prohibit the recognition and enforcement of foreign judgments, prohibit cooperation with foreign court proceedings or provide for the recovery of damages suffered as a result of extraterritorial enforcement measures. Examples of such statutes are the UK’s Protection of Trading Interests Act 1980 ([20 March 1980] (1982) 21 ILM 834) and the EU’s Council Regulation (EC) 2271/96 of 22 November 1996 on the Protection against the Effects of the Extra-Territorial Application of Legislation Adopted by a Third Country, and Actions Based thereon or Resulting therefrom ([1996] OJ L309/1, 6), both adopted in response to legislation with a contested extraterritorial reach by the US.

G.  Evaluation

28  Extraterritorial enforcement action without the consent of the host State clearly remains prohibited under international law. However, the exercise of extraterritorial jurisdiction by way of prescription and adjudication is on the rise. This may cause difficulties if, for example, a merger between two companies is approved in one State and refused in another. Problems of conflicting jurisdiction may be resolved through international cooperation and harmonization of standards. There appears to be a certain amount of convergence of State practice, at least between the US and the EU, in the important area of economic and commercial policies. Representatives of the US and the EU now occasionally consult on the approval of mergers, for example. This should contribute to the prevention of conflicts and the development of a consensus on what is and what is not permitted. At the same time, an increasing number of treaties in the field of international criminal law have codified the principles of extraterritorial jurisdiction in accordance with which perpetrators of crimes under international law—such as human rights violators, terrorists and drug-traffickers—may be brought to justice outside the countries in which they committed their offences. As these treaty provisions are increasingly being relied upon as a legal basis for bringing offenders to trial, this generates a steady flow of judgments further legitimizing the exercise of jurisdiction in respect of crimes committed abroad.

29  According to some observers, the time may therefore now be ripe for a codification of the general rules and principles applicable to the exercise of extraterritorial jurisdiction. This codification might provide, for example, that in order validly to exercise jurisdiction extraterritorially over a person, property, or event, a State must have a sufficient degree of connection to this person, property or event. A valid prima facie connection could be asserted with reference to one or more of the principles of jurisdiction listed above. The codification might also distinguish between types of extraterritorial jurisdiction which are less intrusive and therefore less likely to conflict with other States’ conduct such as prescription, on the one hand, and more problematic forms such as enforcement, on the other. The codification might furthermore provide that the exercise of extraterritorial jurisdiction is subject to certain limitations. Accordingly, it may not be incompatible with the prohibition of interference with the territorial integrity of other States and the prohibition of intervention in their internal affairs. Following the approach adopted in the Restatement (Third) of Foreign Relations Law of the United States, the codification might also provide that the exercise of jurisdiction should be ‘reasonable’ and not contrary to the principles of comity.

30  It is doubtful, however, whether the time is really ripe for such an ambitious general codification of the entire field of extraterritorial jurisdiction. Indeed, it is doubtful whether meaningful rules can be conjured up at all. The topic extraterritorial jurisdiction has been on the long-term programme of work of the International Law Commission (ILC) since 2006 but no work has been done on it so far except for a note by the Secretariat (UN ILC ‘Extraterritorial Jurisdiction’; see also Codification and Progressive Development of International Law). Therefore, it may be necessary for some time to come to attempt to pursue accommodation on a sectoral basis and to formulate rules and principles applicable to certain regimes of international law only.