Few words are more emotionally charged than ‘terrorism’ and ‘terrorist’. They are used to denote conduct that is not only criminal but also – worse – action that strikes at the heart of the people or the fundament of the nation State. On occasion, condemnation in such egregious terms can disclose more about the user than it does about the target of their denunciation. Sometimes those designated as terrorists may bask in the descriptor, wearing it as a badge of honour. But far more often, the recipients reject their label on the basis that either their raison d’être or their tactics, or both, are dedicated to the achievement of lofty goals: freedom, religious purity, the quest for social justice, or the defence of the oppressed or the economically vulnerable. As Adam Roberts, an expert on political violence, says, the word terrorism is confusing and dangerous but also ‘indispensable’.Footnote 1
While the etymology of the root of the word to terrorize is found in ancient Greek, and terror tactics have been employed throughout human history,Footnote 2 we have the French of the late eighteenth century of the current era (CE) to thank for the transmission into English of contemporary understandings of terrorism. Along with his Revolutionary colleagues, Maximilien Robespierre – a lawyer by profession – espoused and vaunted ‘La Terreur’ as a crucial mechanism in the sustenance of the French Revolution against the constant threats of its reversal by monarchists. Republican France thus employed brutality during the Reign of Terror not just as an incidental stratagem of governance but also as wilful, even existential State policy.Footnote 3
Since then, whether in any given society it has been predominantly States or non-State armed groups that have engaged in terrorism has waxed and waned, at least in popular perception, at variance depending on the epoch and the regime. For instance, in the lead up to and throughout the Second World War, the Nazis used terror to maintain their control over Germany and the territories they forcibly occupied. This they did with relentless fervour right until the regime’s bloody denouement in May 1945. In contrast, the 9/11 attacks have done much to imprint non-State Islamist terrorism as the predominant threat to Western civilization in the twenty-first century. First al-Qaeda, and then more recently the Islamic State that it spawned, have sought to replace democratic institutions with religious diktat and dedicated cruelty, moving from war crimes to crimes against humanity to genocide. Most frequently, however, the two types of armed entity – State and non-State – terrorize in ever-expanding lockstep: action provoking reaction and counteraction until the spiralling brutality wrought by each is almost symbiotic.
The Context and the Aim of the Book
The aim of this book is to describe the content of a relatively new branch of international law. While, as discussed here, Member States of the League of Nations elaborated a treaty against terrorism in the second half of the 1930s, it never entered into force. Thereafter, it was not until the early 1970s that efforts were renewed with a view to defining and suppressing terrorism. Piecemeal and sporadic efforts at global and regional levels have generated a myriad of conventions but no unitary definition. International counterterrorism law is thus an amalgam of instruments and legal provisions, a complex set of sectoral treaties informed and influenced by international human rights law, international humanitarian law, and resolutions of the United Nations (UN) Security Council.Footnote 4
Under the umbrella term of international counterterrorism law, terrorism itself can potentially be a targeted killing or an act of indiscriminate violence. In theory, any weapon can be used to commit an act of terrorism. It can be perpetrated by an insurgent, a traitor, the member of a drug cartel, or a lone wolf, as well as by an agent of a State. Indeed, even an act ostensibly of counterterrorism can itself be a terrorist act. What distinguishes a homicide from a terrorist murder under international law is a confluence of the status of the victim, the circumstances of the killing, and the intent of the killer.
Particular opprobrium is heaped on anyone deemed to be a terrorist, even though across national legal regimes such a person – man or woman, boy or girl – is defined in starkly different terms. But, howsoever any national jurisdiction prohibits terrorism in its domestic law, international law will still be relevant to that determination. It may sometimes deny the legitimacy of the label. It certainly regulates the treatment of anyone suspected of terrorist acts or inclinations, including their surveillance, the restriction of their rights, their detention and interrogation, their prosecution, and, upon conviction, their incarceration. International law will further determine the heavily constrained circumstances of if, when, and how a convicted terrorist may lawfully be executed.
Accordingly, this book describes the regulation of both terrorism and counterterrorism under international law. The legality of acts and measures to confront terrorism is to be assessed by reference to international human rights law and the law of law enforcement, as well as, when those acts and measures are directly related to armed conflict, international humanitarian law. Certain acts of terrorism rise to the level of international crimes, necessitating consideration of the personal responsibility of individuals under international criminal law. Especially (but not only) when force is used extraterritorially, jus ad bellum – the law on inter-State use of force – will also apply. In all cases where a State organ or agent has committed an internationally wrongful act, it will attract that State’s responsibility under international law.
Counterterrorism overlaps substantially and substantively with counterinsurgency, counterpiracy, as well as efforts to tackle arms, drug, and human trafficking. Nonetheless, a relatively coherent (albeit fragmented) corpus of international law details the repression of terrorism and terrorist acts in criminal law and regulates the response of States in both law and practice. Articulating the contours and content of international counterterrorism law is the aim of this book. In so doing, however, the book is not a legal commentary on the ‘Global War on Terror’, for such a work has already been largely written.Footnote 5 That said, analysis of the lawfulness of actions taken by the United States and its allies does by necessity feature prominently in this book for, since the beginning of the twenty-first century, terrorism has indeed been ‘the number one issue in international politics, security and law’.Footnote 6 But international counterterrorism law did not begin with the attacks against the United States on 11 September 2001, because – for the truism bears repeating – terrorism as a phenomenon did not start with 9/11.
The League of Nations’ Terrorism Convention
Almost 100 years ago, Romania asked the League of Nations to consider drafting a ‘convention to render terrorism universally punishable’. But the request made in 1926 was not acted upon at the time.Footnote 7 Yet only a decade would elapse before events of international significance in France would spur the negotiation by States of the day of a treaty to prevent and punish terrorism. The Convention for the Prevention and Punishment of Terrorism, concluded in 1937 under the auspices of the erstwhile League of Nations, is a landmark in international counterterrorism law, even though it would never become formally binding.Footnote 8 It required the criminalization of terrorism perpetrated against another State (not the territorial State), with terrorism motivation delineated as criminal acts ‘intended or calculated to create a state of terror in the minds of particular persons, or a group of persons or the general public’.Footnote 9
Specifically, the text stipulated that each State was obligated under a ‘principle’ of international law to refrain from encouraging terrorist activities directed against another State and to prevent and punish such activities and to criminalize offences against the life or bodily integrity of foreign diplomats or the property of a foreign State.Footnote 10 The implication was that terrorism was the preserve of non-State actors, even though the Convention did not exclude the possibility that an agent of a State could engage in acts of terrorism. The negotiation of the Convention had been prompted by the 1934 assassination by separatists in Marseilles of the King of Yugoslavia, Alexander I, and the associated, but perhaps not intended, killingFootnote 11 of the French Minister for Foreign Affairs, Jean Louis Barthou.Footnote 12
Even though, along with France, Britain had pushed hard for the Convention’s successful conclusion, it never signed the fruit of the negotiations. In the event, nor did Germany or the United States – contested provisions on extradition and plans for prosecution of offenders at a proposed international criminal tribunal were the core of their opposition.Footnote 13 The League of Nations is of course no more, its impotence laid bare by the conflagrations of the Second World War it was supposed to prevent. Nevertheless, the articulation of the contours of terrorism and the motivation for terrorism in the 1937 Convention are certainly more than just historical curiosities, and their frequent citation by commentators today pays testament to the text’s contemporary relevance.
Terrorism Treaties within the United Nations
The book traces the path of international law on terrorism and counterterrorism in the modern era ever since the abortive efforts of the League of Nations. Following the conclusion of two multilateral treaties under the auspices of the International Civil Aviation OrganizationFootnote 14 governing the hijacking and bombing of aircraft in 1970 and 1971, respectively,Footnote 15 the first UN treaty of particular salience to the issue was the 1973 Convention on Crimes against Internationally Protected Persons.Footnote 16 The Convention was negotiated in response to a spate of kidnappings and killings of diplomatic agents, including the assassination of Karl von Spreti, the Federal Republic of Germany’s Ambassador to Guatemala, in 1970.Footnote 17 Again, therefore, the focus of burgeoning international counterterrorism law was on attacks against a foreign State. But the choice of theme for the first ‘sectoral’ terrorism treatyFootnote 18 was also a reflection of the inability of the international community to agree upon a general definition of international terrorism.
The conclusion of the Internationally Protected Persons Convention was followed in 1979 by another sectoral treaty, this time on hostage-taking, another common terrorist tactic in the 1970s. The 1979 Hostage-Taking ConventionFootnote 19 was the ‘first attempt to prescribe an offence with a “terrorist motive”’, that is to say, to seek to compel conduct by others through unlawful action.Footnote 20 That said, the Convention employs the term ‘terrorism’ only once, and only in the preamble, reflecting the polemic already affecting use of the term.Footnote 21 The putative States Parties thus declared themselves convinced of the ‘urgent necessity’ to improve international cooperation in support of effective measures to prevent, prosecute, and punish all acts of the taking of hostages – ‘as manifestations of international terrorism’.Footnote 22 The distinction drawn between international terrorism and purely ‘domestic’ terrorism, where crime, victims, and offenders are all in the same State, is addressed in more detail in Chapter 1.
In the decades following the adoption of the Hostage-Taking Convention, UN Member States concluded a series of global treaties on different forms of terrorism within the auspices of the United Nations. Of particular note are the 1997 Terrorist Bombings ConventionFootnote 23 and the 1999 Terrorism Financing Convention,Footnote 24 the latter being the most widely ratified UN counterterrorism treaty with 190 States Parties among the 197 that could adhere.Footnote 25 At the time of writing, the most recent global counterterrorism treaty was the Nuclear Terrorism Convention, concluded in 2005.Footnote 26 Its negotiation had begun in 1998 with a draft proffered by Russia,Footnote 27 which stated that the proposed convention was particularly significant insofar as it was the first international legal instrument in the domain of counterterrorism that was specially designed as a ‘pre-emptive instrument’.Footnote 28
What has still not been adopted under UN auspices is a ‘comprehensive’ convention on international terrorism, even though it has already been more than twenty years in the making.Footnote 29 The principal sticking point between States remains the precise contours of the definition of international terrorism, which continues to elude general agreement, let alone consensus. Consequently, as the International Criminal Tribunal for the former Yugoslavia (ICTY) observed in 2003, the offence of international terrorism has ‘never been singly defined under international law’.Footnote 30 Regrettably, this statement of more than twenty years’ vintage remains true today. A number of generalized counterterrorism treaties have, though, been successfully concluded at regional levels, each with its own particular definition.
Although much – sometimes too much – is made of UN Security Council Resolution 1373, adopted in the aftermath of 9/11,Footnote 31 it nonetheless binds all UN Member States (and purports to bind all States), demanding that they put in place a wide range of regulatory and legislative measures to prevent terrorism.Footnote 32 This is so despite the ‘far from satisfactory situation’ in which the Council becomes the legislatorFootnote 33 and albeit without it even clearly defining what terrorism is.Footnote 34 In 1998, following the terrorist bombings by al-Qaeda in Nairobi and Dar es Salaam in East Africa, the Council had declared that the suppression of acts of international terrorism was ‘essential’ for international peace and security.Footnote 35 But while primary responsibility for the maintenance of international peace and security is generally delegated to the Security Council,Footnote 36 the Council has continued to affirm that UN Member States have the primary responsibility for countering terrorist acts.Footnote 37
The UN General Assembly too continues to be active on the issue. As Boulden observes, this global body adopted more than 110 resolutions on different aspects of terrorism between 1972 and 2020.Footnote 38 In September 2005, the World Summit Outcome document strongly condemned ‘terrorism in all its forms and manifestations, committed by whomever, wherever, and for whatever purposes’, terming it ‘one of the most serious threats to international peace and security’.Footnote 39 In December 2021, in the 76th Session of the Assembly, three such resolutions were adopted, on each occasion without a vote, demonstrating a solidarity that is not always replicated in State practice. In 2022, the 77th Session of the Assembly passed a further four resolutions (two of which were contested). The resolutions concerned measures to eliminate international terrorism;Footnote 40 preventing the acquisition of radioactive sources by terrorists;Footnote 41 measures to prevent terrorists from acquiring weapons of mass destruction;Footnote 42 and the designation of an International Day for the Prevention of Violent Extremism as and When Conducive to Terrorism.Footnote 43 Over the course of the last fifty years, the General Assembly has also taken overall charge of the elaboration of most of the global treaties on terrorism, mandating committees and working groups to take responsibility for their drafting.
In sum, international counterterrorism law comprises a patchwork of treaties, along with a number of customary rules and a set of general principles of law. These are supplemented by a swathe of international, regional, and domestic caselaw and the doctrinal views of leading jurists, as well as soft law instruments and politically binding resolutions promulgated both within and outside the United Nations. By synthesizing and analysing these rules, norms, and decisions, it is sought to bring a modicum of clarity to a complex branch of international law. Descriptions of acts of terrorism and related judicial decisions serve as illustrations both of the existence of rules and of their breach.
The Layout of the Book
Following this Introduction, the book is organized in eight chapters. Chapter 1 is dedicated to the multiple definitions of terrorism that exist in the absence of the adoption of the long-discussed Comprehensive Convention against International Terrorism as well as other definitions outside that Convention’s ostensible purview. The key components of international counterterrorism law are then articulated in Chapter 2, starting with a summary of the key UN treaties on terrorism along with an overview of the content and impact of human rights law, humanitarian law, jus ad bellum, refugee law, and international criminal law.
Coverage of international terrorism concerns especially the 1973 Internationally Protected Persons Convention, the 1979 Hostage-Taking Convention, the 1997 Terrorist Bombings Convention, the 1999 Terrorism Financing Convention, and the 2005 Nuclear Terrorism Convention, along with relevant aerial and maritime treaties. At the regional level, detailed consideration of relevant instruments includes the 1977 European Convention on the Suppression of Terrorism and the 2005 European Convention on the Prevention of Terrorism; the 1987 South Asian Association for Regional Cooperation (SAARC) Regional Convention on the Suppression of Terrorism; the 1998 Arab Convention on the Suppression of Terrorism; the 1999 Organisation of Islamic Cooperation (OIC) Convention on Combating International Terrorism; the 1999 Algiers Convention on the Prevention and Combating of Terrorism and its 2004 Protocol; the 2002 Inter-American Convention against Terrorism; and the 2007 Association of Southeast Nations (ASEAN) Convention on Counter Terrorism.
Analysis of national terrorism legislation in Chapter 3 covers the definitions of crimes and available sentences in domestic jurisdictions, drawing on the practice across every one of the 197 StatesFootnote 44 recognized by the UN Secretary-General in his capacity as treaty depositary. The unique nature and vastly varying breadth of terrorism across States is a remarkable feature of counterterrorism law. Chapter 4 moves on to consider the prosecution of terrorism suspects at national level. The chapter first considers sentences for terrorism in domestic law around the world, including the imposition of the death penalty and maximum sentences of imprisonment for terrorism offences. It then considers the conduct and outcome of selected terrorism cases, grouped regionally: in Brazil, Canada, El Salvador, Mexico, and the United States in the Americas; in Australia, China, Iran, Iraq, Lebanon, and Saudi Arabia in Asia and the Middle East; in Algeria, Kenya, Niger, and Somalia in Africa; and in Belgium, France, and the United Kingdom in Europe.
Operational surveillance of criminal suspects and individuals ‘of particular concern’ raises significant human rights issues, especially pertaining to the right of privacy and later the right to fair trial. The use of force against terrorist suspects by law enforcement agencies, whether in custody or in an extra-custodial situation, also brings into play the rights to life and to freedom from torture. These issues are tackled in Chapter 5. As two judges of the European Court of Human Rights observed in 2008: ‘States are not allowed to combat international terrorism at all costs. They must not resort to methods which undermine the very values they seek to protect.’Footnote 45
Despite the plethora of rules governing terrorism under international law, it would be a mistake to presume that terrorism is, per se, a specific international crime. That said, many terrorist acts are subject to punishment, whether as a war crime, as a crime against humanity, as well as, potentially, as genocide. An act of aggression can involve an act or multiple acts of terror. Chapter 6 thus considers the prosecution of terrorism under international criminal law. Certainly, the victims of terrorism should receive assistance to support their recovery and compensation for their losses, as Chapter 7 considers when looking at the responsibility of States under international law.
Outlook, the final chapter of the book, looks at terrorist threats that have been emerging in recent years or are on the horizon and the extent to which they are covered by extant international counterterrorism law. These include cyberterrorism and the use of fully autonomous weapons in counterterrorism. The book concludes with an assessment of the potential for the successful conclusion of the UN Comprehensive Convention against International Terrorism in the near future as well as for the – more probable – greater fragmentation of international counterterrorism law in the years to come.
A Brief History of Terrorism
Before turning to the consideration of contemporary international counterterrorism law, however, a brief historical perspective of terrorism is offered. Naturally, no history of terrorism could ever hope to be comprehensive; what follows, therefore, is by definition a succinct and partial representation of selected key events and issues. Fear is a form of control and a means to maintain power, as regimes great and small have demonstrated for millennia. Others might legitimately have chosen different events.
Furthermore, one should really begin with the existence of homo sapiens as a species, for terror tactics are as old as the animal kingdom, and human history from its earliest moments is replete with examples. But given the etymology of the term terrorism, the classical world is perhaps as good a place as any to start. For the word is first found in ancient Greek and, more directly with regard to its contemporary meaning, in later-age Latin. While the term is often used loosely and with a degree of abandon, what is at the core of terrorism is the employment of certain tactics and/or the choice of a number of targets. This explains the term’s foundation in the Latin word terrere, meaning to frighten; to alarm; or to deter by provoking great fear. The Latin, in turn, has a cognate in the Greek τρέω, meaning to flee in fear or to be afraid of. Homer, for instance, used the verb on numerous occasions in The Iliad.Footnote 46 Of course, the fact that I may feel terrorized as a result of the actions of a particular person does not mean that the perpetrator of that conduct is, in legal parlance, a terrorist. Indeed, his or her actions may not even be criminal in any objectively rational assessment. Hence, the legal interrelationship between the actions, intent, and perceptions of the subject and object is intricate, or, at the least, rather more nuanced than one might instinctively expect.
The Romans employed crucifixion as a brutal form of capital punishment in part to deter others from rising up against the empire, an early counterinsurgency/counterterrorism mechanism that employed terror as its modus operandi.Footnote 47 Jesus was thus crucified on the basis that he had instigated rebellion against Rome.Footnote 48 But the Romans did not invent crucifixion: responsibility is often attributed to the Persians who developed the technique somewhere between 400 and 300 BCE.Footnote 49 Crucifixion is a method of capital punishment in which the victim is tied or nailed to a large wooden cross or beam and left hanging until eventual death from either exhaustion or asphyxiation or a combination of the two. It is described by one commentator as ‘quite possibly the most painful death ever invented by humankind’.Footnote 50 As a consequence, the word ‘excruciating’ in English is derived from crucifixion, reflecting the slow but extreme suffering it engenders.Footnote 51
Fourteen centuries later, in medieval Europe, Vlad ‘the Impaler’ was a prince whose bloodthirsty acts would later inspire the fictional creation by Bram Stoker of the world’s most famous vampire, Dracula.Footnote 52 Vlad III, whose epithet was only accorded to him post-mortem, had been held captive by the Turks for a while, a condition that weighed heavily on him. After his father was ousted as ruler of Wallachia, Vlad, now free again, launched a campaign to regain authority over his lands. During his captivity, he had seen how the Ottomans would sometimes impale their enemies.Footnote 53 He now used the technique to consolidate his power and strike fear into his enemies.Footnote 54 On one occasion, he invited hundreds of querulous aristocrats – the exact number is uncertain – to a banquet. Knowing his authority would be challenged, he had his guests stabbed and, their bodies still twitching, impaled.Footnote 55 On another occasion, Vlad dined serenely amid an army of defeated warriors who were writhing in agony on impaled poles. At a later time, he had a reported 20,000 people impaled and displayed outside the city of Targoviste. The sight was so horrific that, when confronted with the thousands of decaying bodies being picked apart by crows, the invading Ottoman Sultan, Mehmed II, turned tail and headed back to Constantinople.Footnote 56
Beginning in the late fifteenth century, the Spanish Inquisition used torture to terrify heretics to admit heretical practices. A thousand years earlier, Pope Gregory I had ordered judges not to accept any statement made under torture (although he remained comfortable with burning heretics alive).Footnote 57 But Friar Tomás de Torquemada, the first Inquisitor-General, believed that the devil had to be driven out of the body of heretics by force. He and others of similar persuasion devised a series of the most extreme suffering to be inflicted on the victims of the Inquisition, transmogrifying interrogation of troubled souls into torture ‘as a fine art’. In so doing, ‘he virtually exterminated the Spanish middle class and so crippled Spanish trade that it never completely recovered’. Among many other acts, changing one’s underwear on a Saturday or cutting the fat off meat was clear evidence of heresy.Footnote 58
Sometimes the intent behind terrorism is to retain power, while in other instances it is an attempt to overthrow a regime and seize power, whether on the basis of religious or ideological motivations. The Gunpowder Plot of 1605, the aim of which was to restore a Catholic to the throne of England, is sometimes cast as a planned act of terrorism. Poorly contrived and incompetently executed, it is doubtful the Plot could ever had succeeded. But the amount of decaying explosives hidden under the House of Lords, if actually detonated, could have killed hundreds if not thousands.Footnote 59 In 2005, David Starkey claimed that the ‘parallels between the actions of the plotters and modern-day terrorists are terrifying and the motivation is the same – that religion is the only important thing and that if the Government does not subscribe to the idea that your religion is absolute it must be removed’.Footnote 60 No stranger to controversy,Footnote 61 the historian once described the Gunpowder Plot as the Tudor equivalent of 9/11:
Look at what the plotters did. They put one ton of gunpowder in a room underneath the Houses of Parliament. Had it gone off, it would have killed the king, the chancellor, all the important bishops and judges. It was their Twin Towers and the effect would have been immense.Footnote 62
But the undoubted starting point for discussion of the English term terrorism – as opposed to acts of terror – is the French Revolution. For, as noted above, despite its origins in classical languages, we have late-eighteenth-century CE France to thank for the arrival of ‘terrorism’ (and ‘terrorist’) into English. The words derive from the terms the French came to employ during the French Revolution to describe the newly installed Republican government’s elimination of its vanquished monarchist foes and violent repression of its ‘counter-revolutionary’ enemies. Revolutionary goals were usually pursued through capital punishment at the guillotine.Footnote 63 On other occasions, revolutionary justice would be meted out on the streets in massacres at the hands of roving mobs.Footnote 64
The Reign of Terror (le Règne de la Terreur, or simply ‘la Terreur’) traversed two main periods, a first in 1792 and the second – the ‘Great Terror’Footnote 65 – in 1793–94.Footnote 66 It was a ‘gruesome and protracted’ period of State violence, one that ‘set the political tone for much of the use of these words ever since’.Footnote 67 Central to the Great Terror – its ‘charter’ in the words of the historian Simon Schama – was the Law of Suspects, a decree passed on 17 September 1793 by the euphemistically named ‘Committee of Public Safety’ (as illustrated on the cover of this book).Footnote 68 The Law authorized the creation of revolutionary tribunals to try those suspected of treason against the Republic and to punish the convicted with death.Footnote 69 Even hoarding food staples would be made a capital offence, while the criteria for arrest were so ‘elastic’ that the prisons would swell to around 7,000 in Paris alone.Footnote 70 The Committee of Public Safety would swiftly become the most concentrated State machine France had ever experienced, with revolutionary leaders engaging in ‘unconscionable slaughter’.Footnote 71
Indeed, Robespierre and the other revolutionary delegates to the French National Convention elected to draft the new Constitution had adopted terror as overt State policy.Footnote 72 Speaking before the Convention, the young jurist declared: ‘Terror is merely justice; prompt, severe, and inflexible. It is therefore an emanation of virtue, and results from the application of democracy to the most pressing needs of the country.’Footnote 73 But terror was not only cruel by design – it was also arbitrary and vengeful in its application as Hibbert illustrates:
Hundreds of innocent people suffered with those whom the Revolutionary Tribunal had some cause to consider guilty, some of them through clerical and administrative errors, or even because their accusers chose not to spare them. Others were denounced by jealous or vindictive neighbours. One victim was fetched from prison to face a charge which had been brought against another prisoner with a similar name. Her protests were silenced by the prosecutor who said casually, ‘Since she’s here, we might as well take her’.Footnote 74
With dozens being guillotined daily at certain times – a macabre record was thirty-two severed heads in only twenty-five minutesFootnote 75 – terror was, Robespierre claimed, only a weapon of oppression when in the hands of despots.Footnote 76 In similarly noted language, Saint-Just, the political philosopher and fellow revolutionary leader, declared that the republic ‘consists in the extermination of everything that opposes it’.Footnote 77 By 1794, however, delegates became increasingly fearful that they too would become victims to the orchestrated and seemingly relentless bloodletting from Robespierre and his Jacobin club allies.Footnote 78 As the revolutionary regime lapsed into factionalism, they accused Robespierre of criminal abuse of power (which, without a hint of irony, they called ‘terrorisme’) and sent him to the guillotine.Footnote 79
The term in French entered the Dictionnaire de l’Académie française, already in its fifth edition, in 1798 to describe a ‘system, regime of terror’.Footnote 80 But despite its use in English since the French Revolution, only in Noah Webster’s final revision of his famous dictionary (the edition of 1840) would he include a definition of terrorism: ‘TERRORISM, n. A state of being terrified, or a state impressing terror’.
That same edition of 1840 also saw the addition of the word ‘terrorist’, drawing on the definition in the Dictionnaire de l’Académie française, with similarly explicit references to the French Revolutionary period: ‘TERRORIST, n. [Fr. terroriste.] (Fr. Hist.) An agent or partisan of the revolutionary tribunal during the reign of terror in France’.Footnote 81 More than 130 years later, in 1973, a further meaning connected to terrorism was added to the relevant entry in Merriam-Webster’s dictionary:Footnote 82 ‘violent or destructive acts (such as bombing) committed by groups in order to intimidate a population or government into granting their demands’.Footnote 83 North American language and culture were thus placing non-State actors front and centre as the architects of terror.
The Oxford English Dictionary has retained the original sense of terrorism pertaining to the French Revolution, but likewise offers a second, more general meaning: ‘A policy intended to strike with terror those against whom it is adopted; the employment of methods of intimidation; the fact of terrorizing or condition of being terrorized.’Footnote 84 More succinct is the corresponding definition in the Cambridge English Dictionary: ‘(threats of) violent action for political purposes’.Footnote 85
In the twentieth century, the Nazis engaged in terrorism as State policy on an unparalleled scale across Europe both prior to and during the Second World War. While it may seem inappropriate to engage in comparative analysis, among the many pogroms perpetrated since the French Revolution, the terror inflicted by the Nazis across Europe beginning in the late 1930s and through to their ultimate defeat in April 1945 is totemic.Footnote 86 The Holocaust against the Jews is the greatest single crime of human history. In Eastern Europe, the atrocities perpetrated by the Einsatzgruppen, the Schutzstaffel (SS) paramilitary death squads, were based, in Benjamin Ferencz’s words, on ‘the principles of unmitigated terror and murder’.Footnote 87 In concluding his opening remarks for the prosecution in the trial of a chosen twenty-three of their commanders, which opened in September 1947, he stated:
The judgment of the International Military Tribunal declares that two million Jews were murdered by the Einsatzgruppen and other units of the Security Police.Footnote 88 The defendants in the dock were the cruel executioners, whose terror wrote the blackest page in human history. Death was their tool and life their toy. If these men be immune, then law has lost its meaning and man must live in fear.Footnote 89
Hitler’s nemesis, Joseph Stalin, had himself perpetrated massacres on a massive scale in the 1930s. The Great Purge, also known as the ‘Great Terror’ (a retrospective term which historians have borrowed from the French Revolution),Footnote 90 was Stalin’s campaign in 1936–38 to eliminate dissent within the Communist Party and anyone else he deemed a threat to his leadership. Although estimates vary widely, as many as 750,000 people are believed to have been executed and more than a million others were dispatched to gulags (forced labour camps).Footnote 91 Stalin signed a decree making families liable for crimes committed by a husband or father, meaning that children as young as twelve could be subject to the death penalty. As many as 81 of the 103 generals and admirals in the Soviet Union were executed, initially rendering the Soviet armed forces unable to resist Operation Barbarossa, the German invasion of Russia in 1941.Footnote 92 Millions of Soviet citizens would die unnecessarily as a result.
A Brief History of Terrorism since the Second World War
Outside the Soviet Union, terrorism persisted – and in many instances flourished – after the end of the Second World War. Sometimes terror has been the work of organs or agents of the State, while in other instances non-State armed groups have been its primary instigators. The targets have been political opponents, ethnic minorities, and adherents of other religions. Since then, however, the perception has become widespread that terrorism is primarily the work of non-State armed groups, a tendency that has been accentuated by prominent attacks in recent decades. The 9/11 attacks made al-Qaeda the ‘exemplar’ of global terrorism in the first decade of the twenty-first century; in this it was replaced in the second decade by Islamic State.Footnote 93 Accordingly, although the origin of the term terrorism was State action, it has broadened to encompass any group that uses terror tactics as its modus operandi.
Genocide, the term coined by Raphael Lemkin in 1944 to describe the Holocaust against the Jews, was formally outlawed by United Nations treaty four years later.Footnote 94 But this ‘odious scourge’, as the Preamble to the 1948 Genocide Convention terms an attempt by a State or an armed group to destroy a minority group, would not be outlawed in practice. Since 1945, genocide has been perpetrated against, among others, Mayans in Guatemala (in 1982–83); Kurds in Iraq (in February–September 1988); Tutsis in Rwanda (in April–July 1994); Muslims in Bosnia and Herzegovina (in July 1995); Darfurians (belonging to Fur, Masalit and Zaghawa groups) in Sudan (in 2003–08); Yazidis in Iraq (in 2014–16); and Rohingya in Myanmar (in October 2016–January 2017 and subsequently). Wherever genocide has been perpetrated, terror is invariably at its heart.
The genocide in Rwanda in 1994 is perhaps the most notorious example of the second half of the twentieth century of the international ‘crime of crimes’. Based on detailed analysis of data for one province, Verpoorten has estimated that between 600,000 and 800,000 Tutsis were murdered, with only some 30 per cent of the pre-genocide Tutsi population surviving.Footnote 95 Machetes were the weapon of choice for many of the Hutus responsible, particularly the Interahamwe militia.
Félicien Kabuga, a Rwandan businessman arrested in Paris in May 2020, had gone on trial before the UN Residual Mechanism that followed the closure of the International Criminal Tribunal for Rwanda (ICTR) accused of assisting and inciting the perpetration of genocide.Footnote 96 It had been widely reported that, in the months leading up to the genocide, 581 tonnes of machetes were imported by supporters of the Habyarimana regime. Mr Kabuga was accused of using his companies to import vast quantities of machetes for supply to the génocidaires for the purpose of genocide.Footnote 97 Although the charges relating to the importation of the machetes were later dropped (with the requisite mens rea difficult to prove), the prosecution was seeking to sustain in fact and in law that Kabuga was directly responsible for the content of broadcasts on Radio-Télévision des mille collines that incited genocide; that he provided moral, logistical, material, and financial support to the Interahamwe in the capital, Kigali, and in the prefectures of Gisenyi and Kibuye; and that he distributed machetes to the Interahamwe with complicit genocidal intent.Footnote 98 But in June 2023, Mr Kabuga’s dementia brought the trial to a premature halt. In August, judges in the Appeals Chamber rejected an ‘alternative finding procedure’ whose aim would have been to provide some measure of justice for the victims. The Trial Chamber was instructed to impose an indefinite stay of proceedings ‘in view of Mr Kabuga’s lack of fitness to stand trial’.Footnote 99
A far less well-known genocide is the slaughter of indigenous Mayans in Guatemala in the early 1980s. In the 1970s, the Maya had been protesting against the country’s repressive government, calling for greater equality and inclusion of the Mayan language and culture. In 1980, the Guatemalan army instituted ‘Operation Sophia’,Footnote 100 which sought to end an insurgency by destroying the civilian base in which the guerrillas hid. The programme specifically targeted the Mayan population.Footnote 101 Over the next three years, the army destroyed 626 villages, killed or forcibly disappeared more than 200,000 people, and displaced a further 1.5 million internally. The army’s scorched-earth policy involved the destruction or burning of buildings and crops, the slaughter of livestock, the fouling of water supplies, and the violation of sacred places and cultural symbols. In addition to the army’s special units (known as the ‘Kaibiles’), private death squads were employed for the operation. The US government gave significant support to the Guatemalan regimes in furtherance of its anti-Communist campaigns during the Cold War.Footnote 102 In February 1999, the UN-supported Commission of Historical Clarification released its report, Guatemala: Memory of Silence, which concluded the army had committed genocide against four specific groups: the Ixil Mayas; the Q’anjob’al and Chuj Mayas; the K’iche’ Mayas of Joyabaj, Zacualpa, and Chiché; and the Achi Mayas.Footnote 103
Terror has also been a common feature of crimes against humanity, that is to say, crimes committed in the course of a widespread or systematic attack against a civilian population. One of the means by which terror is perpetrated is in the course of indiscriminate bombing, whether that occurs within or outside international armed conflicts. Vietnam is one of the best known examples of a conflict where all sides carried out atrocities. North Vietnamese regular forces and Vietcong guerrillas engaged in widespread and systematic acts of terror across South Vietnam. For most of this period, the US Air Force was bombing North Vietnam as well as neighbouring Cambodia and Laos, cumulatively dropping more bombs than were used in the whole of the Second World War. Millions were killed or seriously injured, the majority civilians. Ground offensives in South Vietnam also killed many women and children. During the Tet offensive in 1968, one US commander is reported to have uttered the memorable phrase (or something akin to it): ‘It became necessary to destroy the town in order to save it.’Footnote 104 The US bombing of Cambodia would give rise to the Khmer Rouge, whose Kampuchean regime under Pol Pot would see another two million murdered.
Terrorism would also flourish at home in the United States. But as Brian Michael Jenkins remarks, and despite the heavy toll of 9/11, the incidence of terrorism has declined dramatically since the 1970s. In that decade, 1,470 separate acts of terrorism unfolded within the nation’s borders and 184 people were killed.Footnote 105 As Jenkins further noted:
Terrorists perfected their tactical repertoire in the 1970s. They employed six basic tactics, some of which had been practised for centuries: assassination, bombing, kidnapping, airline hijacking, barricaded hostage situations and armed assaults. Assassination had emerged as a terrorist tactic in the 11th century. With the invention of dynamite in the 19th century, terrorist bombings became increasingly common – and remain the most common terrorist tactic.Footnote 106
Palestinian groups and those supportive of the Palestinians engaged in terror attacks around the world from the early 1970s. The killing of Israeli athletes at the Munich Olympic Games in 1972 was only one of a number of incidents that shocked the world.Footnote 107 Members of the Black September group stormed the athletes’ apartment in the Olympic Village, killing two of the group and taking nine others hostage. In return for the release of the hostages, they demanded that Israel release more than 230 Arab prisoners being held in Israeli jails as well as two German terrorists. In a later shootout at Munich airport, all nine Israeli hostages were killed along with five terrorists and one West German policeman.Footnote 108
Carlos ‘the Jackal’, whose real name is Ilich Ramírez Sánchez, is a Venezuelan national currently serving a life sentence in prison in France for terrorist offences under French law. In September 2021, the life sentence given to the Marxist supporter of the Palestinian cause four years earlier for a deadly grenade attack on a Paris shop in 1974 was confirmed. A member of the Popular Front for the Liberation of Palestine at the time, Carlos denied responsibility for the attack at his trial. Prosecutor Remi Crosson du Cormier declared that democracy had ‘two principal enemies – totalitarianism and terrorism’, suggesting that Mr Ramírez Sánchez was among those ‘who threaten democracy by their actions’. At his trial he told the judge, ‘Yes, I have regrets – because I’m kind-hearted – that I did not kill people I should have killed.’Footnote 109
Carlos, now in his early seventies, is serving separate life sentences for the murders in 1975 of two French policemen and a police informer, as well as for a series of bombings in Paris and Marseille in 1982 and 1983 that killed eleven people and left dozens more injured.Footnote 110 Carlos had become one of the world’s most wanted fugitives as a result of leading the attack in Vienna in 1975 on a meeting of the OPEC (Organization of the Petroleum Exporting Countries) oil cartel.Footnote 111 The ‘Arm of the Arab Revolution’ group called for the liberation of Palestine. The targeting of Arab leaders led to their becoming rather more supportive of the development of both counterterrorism efforts and counterterrorism law under UN auspices.Footnote 112
In the United States, the Oklahoma City bombing of April 1995 had been perpetrated by a domestic terrorist, Timothy McVeigh.Footnote 113 It was the worst act of home-grown terrorism in the nation’s history, with 168 people killed, including 19 children, and hundreds more injured.Footnote 114 Six years later, the attacks on the United States by al-Qaeda changed the world. In the four aircraft hijacked by the 19 terrorists, in the twin towers of the World Trade Center into which two of the aircraft crashed, and at the Pentagon, a cumulative total of almost 3,000 people from more than ninety nations died and thousands more were injured.Footnote 115 al-Qaeda, which means ‘the Base’ in Arabic, had already engaged in acts of terror in Africa, with the bombings of the US embassies in Nairobi and Dar es Salam on 7 August 1998. A total of 224 people died in the blasts and more than 4,500 were wounded, the vast majority Africans.Footnote 116
Islamic State grew out of the unlawful invasion of Iraq in 2003 that was led by the United States with the support of a number of military allies, including the United Kingdom. In the run-up to the invasion, the United States had spoken before the UN Security Council of the significance of Abu Musab al-Zarqawi, a Jordanian national. In making the case for war in Iraq, Secretary of State Colin Powell mistakenly identified him as a crucial link between al-Qaeda and Saddam Hussein’s regime. In fact, he was not even formally a member of al-Qaeda at the time, reportedly being closer to a number of Iranian groups.Footnote 117 But al-Zarqawi would go on to exploit his new-found prominence on the global stage to create al-Qaeda in Iraq. He was killed by a US drone strike in June 2006, shortly after the group had been rebranded the Islamic State of Iraq.Footnote 118 His would be a deadly legacy, for the organization he founded would evolve under the intellectual leadership of his number two, Abu Ali al-Anbari, into one that would drive Iraqi security forces out of key cities in Western Iraq, beginning with Fallujah in December 2013.Footnote 119
In 2014, the group, by then renamed ‘Islamic State’, captured Mosul in Nineveh governorate. Islamic State was now being led by Abu Bakr al-Baghdadi, after the death of Abu Omar al-Baghdadi at the hands of Iraqi and US forces in a joint operation in April 2010.Footnote 120 On 4 July 2014, Abu Bakr al-Baghdadi had declared the establishment of an Islamic caliphate from the pulpit of Mosul’s medieval al-Nuri mosque.Footnote 121 A month later, the ‘Sinjar massacre’ marked the beginning of genocide of Yazidis by Islamic State, with the killing and abduction of thousands of Yazidi men, women, and children in Sinjar city and the surrounding Sinjar district in Nineveh.Footnote 122
Islamic State’s reach penetrated deep into Syria with its nominal headquarters established in Raqqa. At its peak in January 2015, Islamic State controlled an area across Syria and Iraq equivalent to the size of the United Kingdom and had attracted tens of thousands of foreign fighters to its cause.Footnote 123 Its brutality was legendary. In November 2014, the Independent International Commission of Inquiry on the Syrian Arab Republic established by the UN Human Rights Council issued a report entitled ‘Rule of Terror: Living under ISIS in Syria’, in which it described Islamic State as a terrorist group that had ‘become synonymous with extreme violence directed against civilians and captured fighters’.Footnote 124 It stated:
Civilians, including men, women and children, ethnic and religious minorities who remain in ISIS-controlled areas live in fear. Victims and witnesses that fled consistently described being subjected to acts that terrorise and aim to silence the population. … ISIS has beheaded, shot and stoned men, women and children in public spaces in towns and villages across north-eastern Syria. … By orchestrating systematic harm against a civilian population, ISIS has demonstrated its capacity and intent to wilfully apply measures of intimidation and terror, such as violence to life and inhuman treatment inflicting great suffering and injury to bodily integrity.Footnote 125
Islamic State’s overwhelming military defeat in Iraq and Syria in 2017 did not, however, end its use of terror tactics. According to the Syrian Observatory for Human Rights, at least 600 people were killed in dozens of attacks by Islamic State in Syria in 2021.Footnote 126 In Iraq, a double-suicide bombing in January in central Baghdad and a suicide bombing in July in Sadr city each killed more than thirty people.Footnote 127 In February 2022, its (then) latest leader, Abu Ibrahim al-Hashimi al-Qurayshi, was killed in the course of a US raid in Syria; he was reported to have detonated a suicide vest, killing his own children in the process.Footnote 128 In November 2022, Islamic State announced the appointment of his successor, Abu al-Husain al-Husaini al-Quraishi.Footnote 129 He in turn was killed only a few days later, in Syria.Footnote 130
In Syria, the violent repression of peaceful protests during the Arab Spring led to civil war, and terror was a tactic routinely employed by the regime in Damascus. In February 2021, Eyad al-Gharib was convicted and sentenced to fifty-four months’ imprisonment for aiding and abetting crimes against humanity. He had arrested anti-Assad protesters who were then transported to the Al-Khatib centre, a facility known as ‘Hell on Earth’.Footnote 131 In January 2022, a German court sentenced a fifty-eight-year-old Syrian colonel, Anwar Raslan, to life in prison for crimes against humanity for his role in the torture of more than 4,000 people in the same facility. The court heard how detainees were beaten and doused in cold water. Others were raped or hung from the ceiling for hours on end. Torturers tore out the fingernails of their victims and administered electric shocks. One survivor told the media he could hear the screams of people being tortured all day, every day. Thousands died from their suffering.Footnote 132
As this brief historical overview has illustrated, sometimes terrorism is directed at the general population or a segment of it, or a particular minority, while at others it is aimed at a nation’s leadership. Peaceful protest is never to be deemed terrorism under international law, even though it is treated as such in a number of repressive national jurisdictions. Always relevant is the unlawful, often barbaric nature of the act and the intent of the perpetrator, whether that is expressed verbally or in writing or where it is otherwise manifest. These issues are explored in Chapter 1.
Debate though continues to surround the extent to which international law should address the conduct of State actors as terrorism. The United States is at the vanguard of those arguing that treaties should focus on the repression of the activities of non-State actors given that other rules of international law constrain the acts of States. But for a number of other States, especially many within the Non-Aligned Movement (NAM),Footnote 133 the actions of States (and particularly the United States) should also be the focus of attention and not those armed groups representing peoples engaged in a struggle for national liberation. Already in 1973, many States were arguing in the United Nations that State terrorism ‘was the most harmful, noxious, cruel, pernicious or dangerous form of terrorism’.Footnote 134
As a matter of law, it is clear that any entity (State or non-State) and indeed any individual can engage in terrorism, even absent membership of or adherence to an existing terrorist group. It is primarily the intent of the salient individual, group, or entity that distinguishes an ‘ordinary’ crime of murder from a terror attack. That intent may be expressed or it may be inferred from the nature and consequences of the act or acts that are perpetrated. And what is clear from practice is that terrorism may even be perpetrated when a State is ostensibly engaged in counterterrorism. Indiscriminate violence and, a fortiori, violence targeted at civilians is evidence of terror tactics. Such violence can occur on land, at sea, in the air, and even in cyberspace.
