State Practice in Assassination: What is Old is New Again

In July 2024, CNN reported that American and German intelligence agencies had thwarted a Russian plan to kill Armin Papperger, the chief executive of Rheinmetall, a company known as “the largest and most successful German manufacturer of the vital 155mm artillery shells that have become the make-or-break weapon in Ukraine’s grinding war of attrition.” This followed other revelations that an ancient tool of statecraft—assassination—is increasingly being used to influence world affairs.

Previously, on September 18, 2023, Canadian Prime Minister Justin Trudeau announced that Canadian security agencies had been actively “pursuing credible allegations of a potential link between agents of the Government of India and the killing of a Canadian citizen, Hardeep Singh Nijjar.” The Indian government denied involvement, but in November 2023, the U.S. government indicted an Indian national with links to Indian intelligence for an audacious plan to kill American/Canadian Sikh activist Gurpatwant Singh Pannun. The case undermined the Indian government’s denials in the Niijar case, as the indictment connected the two incidents.

These instances are not unique. In the 21st century, assassination has risen repeatedly in the context of the shadow conflict between Iran and its proxies and Israel and the United States. In a recent post on Articles of War, Professor Michael Schmitt analyzed whether the July 2024 Israeli killing of Fuad Shukr, a Hezbollah senior military commander, by a missile strike in Beirut, and the reported death of Ismail Haniyeh, the Chief of Hamas’s Political Bureau in Tehran—also attributed to Israel—constituted “assassinations” under international humanitarian law (IHL). On September 27, 2024, Israel killed the Hezbollah leader, Hassan Nasrallah, by means of an airstrike in Beirut, an event widely reported as an assassination.

On September 19, 2024, Israel announced the arrest of an Israeli citizen who had been recruited by Iranian intelligence to conduct espionage and assassinate either the Israeli Prime Minister or the head of Shin Bet as “revenge for the killing of Hamas leader Ismail Haniyeh in Teheran.” This is not the only alleged assassination plot in the context of hostilities with Iran. Another occurred in the aftermath of the American drone strike in Baghdad on January 2, 2020, that killed the visiting Iranian Major-General Qassem Soleimani and the deputy commander of the Iraqi paramilitary Popular Mobilization Forces, Abu Mahdi al-Muhandis. Reports indicate that Iran has been involved in plots to kill former President Trump and other U.S. officials in retaliation for the death of Major-General Soleimani.

Iran has also been implicated directly or through proxies in plots to kill or take other action against “enemies” of the regime (Israeli and non-Israeli), including political supporters of the Iranian opposition. This includes plots in Europe (see here, here, here, here, and here) and the United States (see here and here). Israel itself has long been linked to assassinations targeting former Nazis, scientists who work in weapons programs, and the leaders of terrorist organizations (see Dan Raviv & Yossi Melman, Spies Against Armageddon: Inside Israel’s Secret Wars, p. 281). A particular focus in recent years has been the targeting of Iranian nuclear scientists, including the November 2020 killing of Iran’s top scientist, Mohsen Fakhrizadeh, outside Tehran, allegedly by means of an artificial intelligence-assisted machine gun remotely controlled by satellite.

A clear acknowledgment—even a degree of public acceptance—of such activity is perhaps best represented by the creation of Tehran, an Apple TV+ television show about undercover Mossad agents who carry out operations in Iran, including assassination. Other States have reportedly carried out or plotted attacks against opponents either internationally or internally, including Ukraine (see here, here, here, and here), Rwanda (hereand here), Pakistan (here and here), Saudi Arabia (here), and China. Regarding China, Roger Faligot outlines in his book, Chinese Spies: From Chairman Mao to Xi Jinping, a 1999 effort by Chinese Guoanbu “cleaners” to track down a founding cyber dissident, “Blondie Wong,” in Europe and Canada (p. 391-92).

This post explores the norm against assassination in peace and war, its relationship to targeting opposing leaders and civilians, the legal framework associated with assassination, its occurrence in shadow conflict, and ultimately the ongoing degradation of the norm.

The Norm Against Assassination

Like “terrorism,” international law does not define the term “assassination.” However, the international legal community broadly uses the term to describe a form of killing during both peace and war. Assassination is historically associated with a radical religious sect in the Middle East called the Assassins. As Bernard Lewis indicates in his book, The Assassins: A Radical Religious Sect in Islam (p. 2), assassination has come to mean “a murder, more particularly one who kills by stealth or treachery, whose victim is a public figure and whose motive is fanaticism or greed.” However, in everyday usage, particularly following 9/11, the term “assassination” encompasses a wide range of attacks involving “killing a specific individual in order to achieve a specific goal—(such as) saving the lives of people the target intends to kill, averting a dangerous act that he is about to perpetrate, and sometimes removing a leader in order to change the course of history” (Ronen Bergman, Rise and Kill First: The Secret History of Israel’s Targeted Assassinations, p. xxi).

Not all States adhere to this expanded use of the term, as lawful targeting under IHL is not assassination at all. For example, according to Ronen Bergman, “

Many people associate assassination with political killing within a State, examples of which include the 1963 assassination of President John F. Kennedy, and the attempted assassinations of President Ronald Reagan in 1981 and former President Donald Trump in 2024. Other examples include the 1970 murder of Canadian politician Pierre Laporte in Montreal by the terrorist group Front de Liberation du Quebec (the FLQ) and the 2007 suicide bombing of former Prime Minister Benazir Bhutto in Pakistan. Assassinations can even precipitate larger armed conflict, as occurred with the 1914 assassination of Archduke Franz Ferdinand.

In ancient times assassination was an acceptable practice of statecraft, even in armed conflict. As a commentary on the 2nd century BCE Indian classic, The Arthrashastra, indicates war is not limited to physical warfare, but includes “Gudayuddha, (or) ‘clandestine war’… covert methods to achieve the objective without actually waging a battle, usually by assassinating the enemy” (p. 676). However, as early as the 17th century, States condemned assassination as injurious to the trust between sovereigns, contrary to a “warrior’s honor,” and linked to disorder and chaos (Ward Thomas, The Ethics of Destruction: Norms and Force in International Relations, p. 57-67).

Applying the concept of assassination in wartime is challenging, as nearly all killing is for a political purpose. Instead, as Professor Schmitt has noted, during armed conflict, assassination is primarily linked to the concept of treachery or perfidy. Treachery is broadly defined as “behaviour that deceives or is not loyal to someone who trusts you.” Importantly, assassination is inconsistent with the idea of open warfare. With the emergence of the nation-State came the development of mass armies. The ideal for warfare became open and more conventional, “using treachery crossed the line from war to assassination,” and “clashes between large masses of men—rather than intrigue—was the proper way for conflicts to be settled” (Thomas, The Ethics of Destruction, p. 63).

The prohibition against assassination during war may be most readily associated with the treacherous wounding, killing, or capture of an opponent (see 1907 Hague Land Warfare Regulations, art. 23(b); 1977 Additional Protocol I, art. 37; and 1998 Rome Statute, arts. 8(2)(b)(xi), 8(2)(e)(ix)). However, it also encompasses a broader range of activities which result in death including, as summarized in Article 23(f) of the Hague Land Warfare Regulations, making “improper use of a flag of truce, of the national flag or of the military insignia and uniform of the enemy, as well as the distinctive badges of the Geneva Convention.”

Furthermore, the use of poison during peace and war is associated with assassination. In this regard, The Arthashastra is replete with references to the use of poison by clandestine agents. Regarding armed conflict, Article 23(a) of the Hague Regulations bans the use of poison. Article 70 of the 1863 Lieber Code identified poisoning as a secretive and dishonourable form of killing that would “put someone out of the pale of the law and usages of war.”

This does not mean the use of poison in the context of assassination is a thing of the past. Examples include Mossad’s alleged involvement in the 1997 attempted poisoning of Khaled Meshal in Jordan (Bergman, Rise and Kill First, p. 453-466), the 2010 poisoning death of Mahmoud Al-Mabhouh in a Dubai hotel (p. 610-24), and the 2022 incident in Tehran involving two Iranian scientists (see here and here). Similarly, in 2023, the wife of Ukraine’s military intelligence commander suffered heavy metals poisoning that required hospitalization and a number of defence intelligence staff fell ill, allegedly the handiwork of would-be assassins operating at the direction of Russian intelligence agents. Russia in particular uses poisoning as a tactic, having been linked to poisonings on numerous occasions, including in the United Kingdom against former Russian intelligence personnel (i.e., the 2006 killing of Alexander Litvinenko and the 2018 attempts against Sergei Skripol).

Notably, assassination encompasses activity that extends beyond treachery. As Article 148 of the 1863 Lieber Code states:

The law of war does not allow proclaiming either an individual belonging to the hostile army, or a citizen, or a subject of the hostile government, an outlaw, who may be slain without trial by any captor any more than the modern law of peace allows such intentional outlawry … . Civilized nations look with horror upon offers of rewards for the assassination of enemies as relapses into barbarism.

Under this view, assassination is associated with forms of “outlawry,” such as executing detainees without trial and offering rewards for killing an enemy. In his 2022 book, Command, Lawrence Freedman indicates that during Saddam Hussein’s 1990 invasion of Kuwait, the 16th Republican Guard Special Forces Brigade infiltrated Kuwait City with the task of seizing the Kuwaiti rulers and giving them the option of cooperating. Execution at the palace awaited the emir if he did not do so, but he ultimately escaped to Saudi Arabia, thereby avoiding what might be called an assassination (p. 262).

Targeting Leaders

The period between 1880 and 1914 has been called the “golden age of assassination,” largely due to the actions of anarchists, revolutionaries, and terrorists (see Christopher Andrew, The Secret World: A History of Intelligence, p. 425-48). However, during this same period, the preference for open warfare resulted in the codification in IHL of the norm against assassination during armed conflict. While not reflected in that law, the norm was particularly strong concerning the targeting of enemy heads of State, even if they were otherwise lawful targets. In other words, the prohibition against assassination was a normative concept broader than the action eventually criminalized under IHL (e.g. treacherous killing, wounding, or capture of an enemy).

The norm against targeting political leaders applied in both peace and war. As an example, an offer in 1939 by the British military attaché serving in Berlin to kill Adolf Hitler by means of a sniper rifle prompted a response from the Foreign Minister, Lord Halifax, saying “We have not reached that stage … when we have to use assassination as a substitute for diplomacy.” During the Second World War, the Special Operations Executive (MI5) and Secret Intelligence Service (MI6) developed plans to assassinate Hitler, though none came to fruition.

The targeting of leaders did extend to senior military personnel. In 1942, Czech agents trained in Britain killed SS General Reinhard Heydrich, and in April 1943—in an attack that did not involve treachery—the United States intercepted and shot down the plane carrying Admiral Isoroku Yamamoto. However, as Max Hastings notes in his 2015 book, The Secret War: Spies Codes and Guerrillas 1939-1945, “

Periodically, killings have extended to national leaders, such as during coups. In 1979, for example, Russian forces entered Afghanistan, spearheaded by special forces units that eliminated the sitting Afghan leader. However, the norm against the assassination of political leaders in peace and war remained a strong one until the end of the 20th century. For example, in the lead-up to the 1990 Gulf War, the Allies put forth (and President George H.W. Bush rejected) a proposal to kill Saddam Hussein (Thomas, The Ethics of Destruction, p. 47-49).

President George W. Bush, on the other hand, did not seem to share his father’s trepidation. The 2003 opening salvos of the invasion of Iraq involved a concerted but unsuccessful effort to kill Saddam Hussein with air strikes. Attacking an enemy leader—even the otherwise lawfully targetable head of the enemy’s armed forces—represented a marked departure from the historical normative rule. As noted above, since then, cross-border attacks on individuals have become more widespread. Another recent attempt at assassination unfolded during Russian efforts to infiltrate Kyiv and kill President Volodymyr Zelensky in the opening stages of Russia’s February 2022 invasion.

Targeting Civilians

As is reflected in the Canadian and Australian IHL manuals (paras. 6.12 and 7.25, respectively), the term “assassination” has also described the killing of a person who is not a combatant (e.g. a non-combatant or “civilian”) for political or religious reasons. Such action violates Article 8(2)(b)(i) of the Rome Statute, which prohibits directing attacks against civilians. This mirrors the peacetime understanding of the term “assassination,” an unlawful killing for a political purpose.

Examples of the alleged killing of civilians include the reported Ukrainian targeting of Aleksandr Dugin, a Russian ultranationalist, in a Moscow suburb, which instead killed his daughter, Daria Dugina, and attacks on “collaborators” in occupied Ukraine who do not appear to have been taking a direct part in hostilities. The Ukrainian SBU reportedly claimed responsibility for killing a former Ukrainian member of parliament, Ilya Kyva, near Moscow, in an attack that raises questions whether a peacetime or wartime legal framework applies. These killings warrant further investigation to determine their lawfulness, as does the alleged Russian targeting of one of its own military pilots in Spain, Maksim Kuzminov, who had defected to Ukraine in August 2023.

The Legal Framework

Assessing assassination first requires consideration of the legal framework under which the killing occurs. In addition to IHL, there are two relevant bodies of law: international human rights law, and the legal framework controlling the State’s use of force in self-defence. Human rights law is particularly relevant to peacetime assassination, although it also continues to operate during armed conflict. In contrast, IHL, a more permissive legal regime regarding the use of force, only applies when an armed conflict exists.

Notably, while Israel has been associated with hundreds of killings throughout its history, “the vast majority of those killings were by army units, mainly in uniform.” One 2012 estimate provided that less than 50 killing operations had been carried out by Mossad (Raviv & Melman, Spies Against Armageddon, p. 281) although there have been more allegations since then. Moreover, Israel has been engaged in a number of long-term armed conflicts, which fall under IHL’s framework. For example, Israel has been at war with Syria since 1967, with considerable hostilities occurring since 2011, and has claimed to continuously be in an armed conflict with Hamas and other Palestinian terrorist organizations since 2000. As I noted in an earlier post it can be argued that Israel is also at war with Iran both directly and indirectly through the application of the “legal effective control,” “substantial involvement,” or “overall control” tests regarding its proxies (e.g., Syria, Hezbollah, and Hamas). This suggests that many Israeli strikes have been “targeted killings,” which are lawful under IHL unless they were carried out treacherously or involved targets not amounting to a lawful military objective.

In assassination discussions, some disagreement may arise concerning the lawfulness of targets. For example, Hays Parks indicated in an influential 1989 memorandum that the killing of “civilian scientists occupying key positions in a weapons program regarded as vital to a nation’s national security or war aims” would not constitute assassination (p. 6). It is not clear how many States would agree with this interpretation given the work by the International Committee of the Red Cross to narrowly interpret “direct participation in hostilities,” and an overall effort to outlaw the concept of quasi-combatants in the post-Second World War era. However, to the extent the Parks interpretation is applicable to Iranian scientists, the issue then becomes whether Israel’s attacks were carried out treacherously (e.g. through use of poison).

Importantly, States have increasingly relied upon the third legal framework, the right to self-defence, to carry out cross-border attacks. Throughout the Cold War, the international legal community interpreted Article 51 of the UN Charter very narrowly. Furthermore, the 1986 Nicaragua case established a gravity threshold regarding its use, although not all States agree with that approach (para. 195). However, an increase in transnational terrorism and technological advances such as the development of armed drones, led to a more expansionist interpretation that justified attacks where a territorial State has been unwilling or unable to deal with the threat.

The United States has repeatedly relied on self-defence, including: the 2008 killing in Damascus of the Hezbollah operations chief, Imad Mughniyeh, carried out in cooperation with Israel; the 2011 raid in Pakistan that killed Osama bin Laden; the 2020 drone strike in Baghdad against Iranian Major-General Qassem Soleimani and Iraqi Popular Mobilization Force leader, Abu Abu Mahdi al-Muhandis; a 2022 drone attack in Kabul against al-Qaeda leader Ayman al-Zawahiri; and a similar attack in 2024 in Baghdad that reportedly killed Iraqi Shiite militia leader Abu Baqir al-Saadi. Claiming to act in self-defence seeks to situate the strikes as lawful “targeted killings” rather than assassinations. Less clear, however, is whether the United States always considered such strikes to have occurred in the context of an armed conflict, and therefore, under IHL’s rules.

The right to act in self-defence operates at the strategic level authorizing the strike, while IHL governs the tactical aspects of such a strike. As I have written elsewhere, although the principles governing self-defence govern State action, either IHL or human rights law regulates the use of force, depending upon whether there is an armed conflict in existence (p. 72-89). A failure to identify the character of the hostilities underpinning defensive responses casts a shadow of uncertainty over the legal basis for the operation. This, in turn, invites allegations of assassination in respect of targeting.

Shadow Conflict

Much of the 21st century’s conflicts in which allegations of assassination arose took place at the lower end of the violence scale. Doctrinal terms developed to address this reality include “gray zone” and “hybrid warfare” (see here and here), “liminal warfare” (see David Kilcullen, The Dragons and the Snakes: How the Rest Learned to Fight the West, p. 152-153), “surrogate warfare” (Andreas Krieg and Jean-Marc Rickli, Surrogate Warfare: The Transformation of War in the Twenty-First Century, p. 4), and in the case of Israel, the “Campaign Between Wars.”

The attacks occur in a political and operational context in which belligerents prioritize public awareness and the limits of international tolerance over the technicalities of international law. As General David Petraeus and Andrew Lloyd note in their 2023 book, Conflict: The Evolution of Warfare from 1945 to Ukraine, “(e)conomic sanctions, targeted assassinations and political influence campaigns are becoming more common, more alluring and in some cases, less detectable than actions on the usual battlegrounds of land, sea, air and space. Perpetual low-level conflict masked by plausible deniability both de-intensifies war and makes it more ubiquitous” (p. 406).

States may rely on a variety of forces to conduct killings in the shadows where “plausible deniability, not firepower, forms the center of gravity” (Sean McFate, The New Rules of War, p. 199). Many actions by forces operating in the shadows—such as the Israeli naval commando sniper rising from the sea in 2008 to kill Syrian Brigadier General Mahmoud Suleiman—are lawful targeted killings in the context of ongoing hostilities. Organizations identified with incidents of cross-border killings and potentially assassination include the Israeli Mossad (i.e., Caesarea /Kidon or “Bayonet” units); Russia’s military intelligence organization, the Main Directorate of the General Staff of the Armed Forces of the Russian Federation; the Iranian Revolutionary Guards Force, Quds Force Unit 840; China’s Ministry of State Security (the Guoanbo); the Security Service of Ukraine, as well as its Military Directorate of Intelligence; and more recently alleged, India’s foreign intelligence service, the Research and Analysis Wing.

When such activity is traceable to the State involved, some States have apparently sometimes entered into murder-for-hire contracts with criminal organizations, such as the Hells Angels (see here and here), the Russian mob network, the “Thieves in Law,” and the Dutch “Mocro mafia,” to carry out the killings. As a result, law enforcement authorities are increasingly involved in thwarting such attacks. This highlights once again that contemporary hostilities frequently occur at the intersection of the legal boundaries of IHL, human rights law, and the law governing State self-defence.

The murky world of shadow conflict has a limited history of accountability. Perception can determine how States approach transnational killing. As reported in the Nijjar killing, “(a) former senior U.S. intelligence official said: ‘This is Modi looking at the world and saying to himself, ‘The United States conducts targeted killings outside of war zones. The Israelis do it. The Saudis do it. The Russians do it. Why not us?’’ And none of the (nations) we just mentioned pay much of a price.” Another report indicates “(o)ne retired Ukrainian intelligence officer grumbled that ‘countries that kill their enemies on the other side of the world with drones can hardly complain about our methods … . This is a fight for Ukraine’s survival. Our allies shouldn’t try to tie our hands or look over our shoulders.’”

Concluding Thoughts

The norm against assassination is being significantly degraded. As such, it represents yet another challenge to the international rules-based order established at the end of the Second World War. In addressing this decline, the international community should take action that not only focuses on accountability, but also on countering the perception that such killing is acceptable. First, the international community must pay greater attention to what is happening in the shadows at the lower end of the violence scale. This includes encouraging media attention to shine a light on the dark corners where such killing occurs.

Second, the international community must challenge States that claim to be acting legally. It should not be sufficient for a State to say it carried out the attack in self-defence. Rather, States should identify the legal framework governing its use of force and explain how such action meets the parameters of IHL or human rights law.

Third, States must demand accountability even if there is an inability at the time to lay charges or commence criminal proceedings. Despite the initial criticism he received, Canadian Prime Minister Justin Trudeau justly condemned the actions of Indian intelligence authorities in the fall of 2023, well before the U.S. government indicted an Indian national for similar action. In the situation of an armed conflict, the international community should demand greater accountability, not only with respect to the actions of opponents and unpopular States, but also from allies. Condemning an opponent for what may be an unlawful killing, but not doing the same for an allied State, significantly undermines the norm against assassination. Finally, as some States have done (see here, here, here, and here), the domestic authorities of each State should investigate and take appropriate action against those within their jurisdiction who are alleged to be involved in assassination. Similar to espionage, and increasingly sabotage, international law does not on its own offer a sufficient impediment for those seeking to carry out assassination in the 21st century.

If the norm against assassination is not reinforced, then perhaps Mark Galeotti offers the most accurate comment on a potentially dystopian future regarding a means of statecraft once viewed as far too treacherous and dishonourable to be permitted. As he notes, “(a)ssassinations have become too difficult to conceal, too provocative to ignore. (And not everyone can rely on drones to kill those they would see dead, or get away with their use.) Instead, though, the state can turn to the professionals in murder when they want to reach out and touch someone” (The Weaponization of Everything: A Field Guide to the New Way of War, p. 116).

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Ken Watkin served for 33 years in the Canadian Forces, including four years (2006-2010) as the Judge Advocate General.

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