Beyond the Law: The Covert Assassination of Iranian Nuclear Scientists


The development of Iran’s nuclear capability has resulted in profoundly complex political affairs for several decades. For Iranian nuclear scientists, these consequences have been fatal.  Since 2007, more than five prominent scientists have fallen victim to covert assassinations tactics, in an attempt to tarnish the very heart of the Iranian nuclear program. Despite the covert nature of the assassinations, sufficient evidence has surfaced tracing their origins back to the National Intelligence Agency of Israel (Mossad). For decades, the threat of a nuclear Iran has directly endangered Israel’s nuclear hegemony within the Middle East – compelling Israel to respond in a legally dubious and morally reprehensible manner.

Through the analysis of various international laws encompassing targeted killings, this paper evaluates the motives, efficacy and repercussions of targeting Iranian nuclear scientists. I offer an analysis of the assassinations through the lens of international humanitarian law, demonstrating salient violations of transnational norms and regulations. The second part of this paper evaluates covert assassination from a strategic policy standpoint, uncovering the unintended and grave consequences of targeting nuclear scientists. Furthermore, I explore the way in which covert assassination undermine global security and defy long-established conventions and pervading norms.


Background: The Assassinations

Targeting of atomic scientists in order to deter state weaponization predates the existence of nuclear weapons themselves. Concerned with the possibility of losing its nuclear monopoly in the region, Israel viewed Iran’s acceleration to nuclear weaponization as a colossal threat. Thus, Mossad created a plan in order to derail Iran’s nuclear pursuits. As part of the plan, five prominent nuclear scientists and physicists were murdered through covert operation. Those targeted included Ardeshir Hosseinpour, a nuclear physicist at the Isfahan uranium conversion plant; Massoud Ali Mohammadi, an expert in quantum physics at Tehran University; Majid Shahriari, an expert on nuclear chain reactions; Darioush Rezae Nejad, a nuclear physicist and researcher for the Iranian Atomic Energy Organization (IAEO); and Mostafa Ahmadi Roshan, a professor at a technical university in Tehran and a department supervisor at the Natanz uranium enrichment plant (Maher). Iran quickly attributed these killings to Israel and the U.S., and Iranian counterintelligence later revealed that Israel had recruited Iranian spies to carry out these covert assassinations. In addition to murdering valuable assets of Iran’s nuclear program, it also created what Mossad regards as “white defection”. The theory follows that fewer Iranian scientists would work on future Iranian projects out of safety concerns, thus denying Iran of valuable scientific expertise.



We start by clarifying the meaning of assassination under international law, and what constitutes an assassination under these terms. While no universally established definition of assassination has prevailed, the common variations contain a singular theme. As explored by Reisman, if an assassination is committed beyond the realm of armed conflict it is defined by having:(I) a specifically targeted victim; and (II) a political motivation. The latter requirement distinguishes an assassination from murder, since it implies an aggressor state rather than an individual. As previous scholars have noted, assassination is viewed as an unlawful covert action and should not be granted “any color of law” (Reisman, 689). They argue that a pattern is emergent: conditional tolerance for assassinations exists at the elite level, hence preventing it from becoming a matter of law.  Due to this, no explicit prohibition of assassination exists within the realm of international law.  For this reason, I adhere to the standard set by Reisman for an assassination for the remainder of this paper. In this case study, the assassination of Iranian nuclear scientists presents highly politicized motives and repercussions, thus they may be evaluated under Reisman’s definition. Lastly, “assassination” and “targeted killing” will be used interchangeably, although the latter is often utilized in the case of targeted terrorist killings. Nonetheless, all interchangeable forms of the “assassination” remain illegal under the realm of international law.


Assassination Under International Law

As often attributed to their covert nature, political assassinations have not been explicitly banned within the framework of international law. Through the analysis of various treaties and conventions, one may properly assess the illegality of assassination within the rights and obligations of a state. The role of customary international law is also critical; as rules of customary law are equally as binding as treaties. In addition to applicable statutes in international law, universal human rights law – presented through the UN Declaration of Human Rights as a critical aspect of customary international law –also provides valuable guidance when assessing targeted killings.


Two prominent bodies of law arise in regards to political assassinations. Firstly, International Humanitarian Law (or “IHL”) or jus in bello, governs the conduct of war in times of armed conflict. Parallel to this, jus ad bellum establishes the requirements needed to enter armed conflict, as set out in the UN Charter and the customary international law of self-defence, such as legitimate authority, public declaration, just cause and war as the final resort. Published in 1944 as part of the famous Geneva Conventions – and before this, the Hague Conventions of 1907 – IHL sets rules for the treatment of combatants and non-combatants alike. The notion of jus in bello further includes the principles of proportionality and discrimination. The former establishes that any harm to civilians must be balanced against the military advantage anticipated from attack, while the latter ensures that legitimate targets, like soldiers, be treated differently from illegitimate targets, such as civilians.


In principle, however, Israel may attempt to justify the assassinations as valid acts of pre-emptive self-defence. The UN Charter recognizes a state’s right to self-defence in Article 51, stating:

“Nothing in this present Charter shall impair the right of individual or collective self-defence if an armed attack occurs against a member of the United Nations, until the Security Council has taken measures to maintain international peace and security. Actions taken by Members in the exercise of this right of self-defence shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain or restore international peace and security.”


The procedural requirement to report to the Security Council reflects the legitimacy and transparency of the state exercising self-defence. Conversely, it presents a narrow window where Israel may operate. Justifying the assassination of nuclear scientists would then require settling a wide array of surrounding political issues; the true gravity of the Iranian threat, the projected expediency of removing such threat, and the precise motives for doing so. Even so, the threat to Israel must be imminent, and the prospect of impeding the threat through assassination must be realistic. As discussed above, these issues encompass provisions of IHL concerned with necessity and proportionality under jus ad bellum.  Still, Israel cannot claim the assassinations were required through Article 51, as they do not meet the requirement of necessity nor immediacy.


Nonetheless, the case of Iran and Israel escapes evaluation under IHL, predominantly because neither state was in a state of “armed conflict” as per the IHL definition. Looking beyond their antagonistic history – often consisting of public and daring threats – the state of Iran and Israel cannot be assessed under the provisions of IHL. From this perspective, no act has risen to the level of an “armed attack”.  The International Criminal Tribunal defines “armed conflict” when there is “a resort to armed forces between states” or “armed violence between governmental authorities and organized armed groups” (International Criminal Tribunal for the Former Yugoslavia, para 70). Under the Geneva Conventions, it is defined as a difference arising between two states, thus “leading to intervention of members of the armed forces.” (Geneva Convention para 1).  These definitions of “armed conflict” fail to encompass the political status quo between Iran and Israel. The public positions of both governments deny a state of armed conflict, and the limited focus on Iranian scientists evade the application of international humanitarian law.


In addition, the basic principles of sovereignty must be considered. Since the establishment of the Peace of Westphalia in 1648, the principle of state sovereignty has become a guiding principle of international law. Westphalian sovereignty protects a state’s exclusive autonomy in its territory while emphasizing the legal equality of states. Article 2(7) of the United Nations Charter emphasizes the domestic jurisdiction of the state; stating that the United Nations has no authority to intervene in matters within the scope of domestic affairs. As enshrined in the United Nations system, Westphalian sovereignty is  a core pillar of the international system of governance.  In accordance to this principle and in the absence of armed conflict, Israel evidently violated Iranian state sovereignty by engaging in a violent act within its territory.


Beyond considerations of international humanitarian law and state sovereignty, human rights law  may be used as a guiding apparatus for evaluation. Under human rights law, it is often believed that a targeted killing is only “legal” – as a last resort – if it is required to protect life. This is only once all other means are exhausted, such as capture, in preventing that threat to life. However, it is important to note that human rights law is embodied through multiple treaties and statutes. The International Covenant on Civil and Political Rights (“ICCPR”) emphasizes the “inherent right to life” that “no one shall be arbitrarily deprived” of (ICCPR, Article 6, para 1). More significantly, the United Nations’ Declaration of Human Rights contends the human “right to life, liberty and security”. Under the declaration, human rights must be protected by the rule of law, and they apply to all humans within and beyond state borders. Thus, states are bound by fundamental human rights when acting within another state. Under human rights law, a state’s actions are not assessed based on territory but rather conduct. With this maxim in mind, a state must conduct operations in accordance to human rights standards “with regard to all individuals who may be under their effective control or who may be directly affected by their actions.” (Mezler, 137).  Even in the absence of state recognition, the United Nations Declaration of Human Rights has become widely accepted as reflecting customary international law, further impelling a state’s motive to comply.


As demonstrated above, there exists a rule of customary international law against violation of a person’s right to life; irrespective of territory, citizenship, and treaty ratification of the involved states. Undoubtedly, the explicit assassination of the Iranian nuclear scientists deprived them of this right to life. As a signatory of the aforementioned treaties, the state of Israel defied its obligations under international human rights law. For an assassination to be “legal” under human rights law, it must be “strictly necessary” and as a final resort to protect life. For Israel, great difficulty persists in establishing the necessity and urgency of the targeting of nuclear scientists.

Israel stands a slightly better chance utilizing the ICCPR in defence of their covert assassination. As aforementioned, the ICCPR forbids the “arbitrary taking of life”, with the components of “arbitrariness” as (I) requirement of a sufficient legal basis; (II) requirement of necessary; (III) requirement of proportionality; and (IV) requirement of precaution. (2006) Once again, Israel runs into the issue of necessity and sufficient legal basis. The UN’s Basic Principles of the Use of Force and Firearms also embody similar principles of the right to life. Parallel to the themes of human rights law, it states that lethal weapons may only be used in self-defence and only when less extreme means are insufficient to achieve these means (1979). It echoes the importance of “non-lethal” means of enforcement in an attempt to protect life.


Policy Considerations and Unintended Consequences

In the absence of international law and the legal implications, the covert campaign against Iran’s nuclear Programme offers valuable insight for the theory and practice of coercive diplomacy. In what remains, I analyze the strategic significance in Israel’s decision to target scientists, and the subsequent unintentional consequences of covert action.


Firstly, it is clear that attacking Iran with military force was an unappealing option for Israel and the U.S. alike. The spillover effects of a full blown war and the consequent risks associated with it prove to be too costly for both states. Similarly, hostility between the states would prevail, along with increasing domestic support for the Islamic regime. It would also create a greater justification to establish an Iranian nuclear program, in the possibility of additional strikes. Within the greater arena of international relations, other states may condemn aggressor states in the event of military action. While the United States and Israel have a far greater military advantage over Iran, brute power asymmetry does not always guarantee a beneficial outcome for the aggressor state. Todd Sechser refers to this phenomenon as ‘Goliath’s Curse’. His research on coercive diplomacy states that as coercers gain more power, their threats may often fail – often because a challenger’s military power “exacerbates information problems that make its threats less likely to succeed” (628). Thus, coercive diplomacy can minimize ‘Goliath’s curse’ by applying the correct amount of pressure on a state, while assuring the likeliness of a state’s willingness to cooperate. Jentleson et al. recognize successful coercive diplomacy as a balance between “credible fore and deft diplomacy” (53). Thus, covert assassinations of Iranian scientists demonstrated the power of Israel and its allies to Iran. It signalled their power to retard Iran’s nuclear efforts. Additionally, the strikes targeted the heart of the nuclear program, representing increasing animosity towards Iran, despite the lack of a full-scale military attack.


As aforementioned, no state has come forward and taken responsibility for the assassination of Iranian scientists. Contemporary literature argues that states have become increasingly concerned with the protection of their reputation, hence the growing prevalence of covert action. Often, the focus is weighted on the reputation of the aggressor state in the face of international shaming. However, the reputation of Iran is equally important in the equation. Beyond international considerations, if Iranian leaders had quickly submitted to the demands of the West, it may have signalled a weak Iranian regime to its domestic population. Sechser notes “when a target capitulates to a threat, it reveals information about the limits of its resolve” (628). In other words, complying with a threat entails reputation costs for Iran, while revealing the perceived strength of the Islamic regime. At the same time, ramping up Iran’s nuclear efforts could have brought even more pressure and coercive action from outside states. States, such as Israel, could utilize Iran’s surge in nuclear efforts as justification for more covert assassinations. Thus, many scholars emphasize Iran’s incremental developments in building a nuclear weapon – in an effort to demonstrate its willpower domestically, while avoiding costly international ramifications. Volpe further asserts that Iran made “incremental advances” in order to “leverage concessions from the international community” (521).


Unintended Consequences

Despite the potential appeal for covert action, an array of unintended – and undesirable – consequences may occur as a result of covert action. More fundamentally, the looming inability to predict the outcomes of one’s action and the prioritization of short term interests over long term diplomacy can further aggravate undesirable consequences. In the context of Iranian counter proliferation, covert assassination may thwart diplomacy, inspire retaliatory measures, spread domestic sympathy for the regime, and undermine the ethical legitimacy of the aggressor states.


For Iran, the covert assassinations proved to be a powerful catalyst in bolstering support for the Islamic regime. Islamic fundamentalists and hardliners utilized the event as justification to further demonize the West during a time of rising fear and anxiety. It may also act as a unifying common enemy among Iranians, further contributing to Western resentment and fulfilling justification for Iran’s nuclear ambitions. After the assassinations, Iran launched a series of media campaigns referring to the scientists as ‘nuclear martyrs’ while parading their images throughout the country. Reports from Iran claim the propaganda-heavy homage to the nuclear scientists was part of Tehran’s strategy to generate public support for its nuclear program (Esfandiari).


In addition to the domestic backlash, aggressor states may face international backlash due to their outward violation of international law. These covert assassinations, as mentioned above, are clear abuses against long withstanding international norms and laws.  Many critics believe that the target of Iranian scientists violated international norms and principles against assassination. As noted by Waldron, assassination cannot operate within a ‘neutral principle’ (5). When contemplating the incorporation of a norm allowing covert assassination within the realm of international law, Waldron urges states to consider whether they would be comfortable with this norm “in the hands of their adversaries”. For Israel, the mere potential for Iran to partake in similar covert assassinations would surely undermine state security.


For these reasons, Waldron also asserts that the norm against political assassinations should be upheld for both strategic and ethical reasons (130). Through this perspective, covert assassinations undermine the broader international norm against killing. Moreover, violating international legal norms may embolden other states to act similarly. From a state’s strategic perspective, the erosion of the norm against covert assassination can prove to be increasingly problematic on an international scale. Fundamentally, these actions undermine valuable international norms which foster accountability and transparency among states.  By granting certain actors the right to covert assassination – justified on the basis that their targets are likely to harm them, or have already done so –the likelihood that all international actors become willing to evade such norms undoubtedly increases. These actors are not limited to the scope of international states, but rather terrorist actors with morally reprehensible ambitions. Whibley states that the power of a state builds on the respect and enforcement aspect of norms, and the way in which states exercise power has direct and indirect effects on the emergence of new norms (121). That is, the emergence of such norms are established by the acknowledgement and enforcement of these norms by other states, through similar practice.



The development of Iran’s nuclear capability has resulted in a prolonged diplomatic standoff with the West, lasting for nearly two decades. In the long run, however, the assassination of nuclear scientists did little for Israel’s benefit. While it disrupted Iran’s nuclear ambitions for a brief moment in time, the assassinations did not completely halt Iran from pursuing nuclear capability. Less than a few months later, Iran ramped up their efforts, which were briefly halted following Obama’s Joint Comprehensive Plan of Action (JCPOA) deal. Iran also paraded the ‘martyrs’ for years to follow, in an attempt to rally public support and prove the ‘need’ for nuclear capability.


Within the greater scope of international affairs, the assassinations – characterized as ethically and legally indefensible – reflect the long term recognition of the international community that erosion of these norms may end up harming their own security. As the Iranian case demonstrates, covert action is unlikely to completely unravel and derail a state’s nuclear ambition, thus a clear understanding of the consequences is significant for future policy implications. This also reveals areas where greater analysis may be beneficial – for example, whether covert assassinations may be an effective tool in deterring future generations and to what degree states will condemn aggressor states. Further, the covert assassination of Iranian scientists presents a myriad of legal, ethical, and policy considerations for future areas of scholarship.


This paper offered an analysis of the assassination of nuclear scientists through the lens of international laws, and long-held established norms. By closely assessing the motives, efficacy, and repercussions of the covert assassinations, I demonstrated the myriad of potential undesirable and unintended consequences for states who violate these international norms. As observed by George Orwell, actions are held to be good or bad, “not on their own merits but according to who does them”. The salient and fatal covert campaign against Iran represents the dangers of shrugging our shoulders and turning a blind eye, as we may unintentionally descend into an era of lawlessness and chaos.


















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