AN ASSESSMENT OF THE LAWFULNESS OF THE KILLING OF QASSEM SOLEIMANI BY THE UNITED STATES AND OF THE IRANIAN RESPONSE UNDER JUS AD BELLUM
by Ellie Cumberbatch*
[A] INTRODUCTION
On 3 January 2020, American drones targeted a convoy leaving Baghdad International Airport in Iraq, killing ten individuals including Iranian Major-General Qasem Soleimani.[1] Five days later, Iran responded with missile attacks on the Ayn Al Asad air base in Iraq, resulting in the severe brain damage of over one hundred United States military personnel.[2] These attacks occurred amid growing military tensions between the United States and Iran,[3] and both uses of force have been justified under the umbrella of self-defence. The U.S. government initially justified the strike as a measure to deter imminent attacks on United States embassies and personnel,[4] but later stated in a letter to the Security Council that the United States’s right to self-defence was invoked by Iran’s actions in the months prior to the strike.[5] Iran took a similar approach; in its letter to the Security Council the ambassador to the U.N. noted that Iran’s “armed forces have been the subject of armed attacks by the United States”, resulting in the armed forces taking “measured and proportionate action in self-defence”.[6]
However, whilst both states have claimed that the acts were necessary and proportional acts of self-defence,[7] a variety of legal theories have been advanced to support the claim that neither uses of force were consistent with the principles of jus ad bellum. Broadly speaking, contemporary jus ad bellum prohibits the use of force with the exception of Security Council measures and acts of self-defence.[8] The right to self-defence is not without limitations, and state practice post-9/11 has increasingly pushed the limits of this legal framework in an effort to expand its scope to include provisions such as pre-emptive self-defence and the “unwilling or unable” doctrine.[9] It is with this tension in mind that this essay will provide an assessment as to whether the targeted strike on Soleimani and the subsequent Iranian response can be considered lawful acts of self-defence under international law.
(1) Applicable legal framework
As noted by UN Special Rapporteur Callamard, the killing of Soleimani is “the first known incident in which a state has invoked self-defence as a justification for an attack against a State actor, in the territory of another State”.[10] Given this clear demonstration of the blurring of the lines between war and peace, it has generated a great deal of contention as to the appropriate legal frameworks to regulate such use of armed force. Despite both states denying that they are “at war”[11], there has been discord as to whether the United States and Iran can be considered to be in an international armed conflict. Consequently, a holistic examination of the international legal frameworks which regulate these uses of force is necessary for a complete assessment of their legality.[12] However, given the complexity of this assessment, and that the application of key jus in bello provisions is arguably contingent upon whether the conditions for jus in bello are satisfied[13], this paper will narrow its scope to provide an extensive initial analysis as to whether the uses of force by the United States and Iran can be regarded as lawful under the right to self-defence.
The legal framework of jus ad bello is provided for by article 2(4) of the United Nations Charter, which proclaims that “all members shall refrain from the threat or use of force against the territorial integrity or political independence of any state”.[14] This is recognised as a binding principle of customary international law and as jus cogens.[15] However, the Charter provides for two exceptions to the prohibition of force: force authorised by the Security Council, and the use of force in self-defence under Article 51.[16] Given that drones are not a prohibited weapon under international law and targeted killings may be regarded as legal acts of self-defence in some circumstances,[17] the lawfulness of the strike on Soleimani and the subsequent Iranian response must therefore be determined by the degree of compliance with Article 51 and relevant customary international law. Although the rules pertaining to the right to self-defence remain a widely debated topic and are therefore difficult to apply in practice,[18] two broad requirements for the lawful use of self-defence can be identified: (1) the existence of an ‘armed attack’ against the state;[19] and (2) a necessary and proportionate use of force.[20]
As a means of structuring an analysis of the lawfulness of the use of force by both States under jus ad bello, this essay will first provide an assessment of the extent to which both the United States and Iran can be considered to have suffered an armed attack, and whether this justifies the breach of Iraqi territorial sovereignty. Secondly, the paper will then go on to determine whether the action undertaken in response to these “armed attacks” was necessary and proportionate, thus falling within the required limitations on the use of force in self-defence. Finally, drawing upon these determinations, an analysis of the paper’s determination of the legality of the cases at hand will be provided. Overall, this essay finds that both uses of force fail to comfortably fit within the “rubric” of self-defence given the lack of substantial evidence supporting the existence of an armed attack or the necessity of both responses, particularly with regards to the violation of Iraqi sovereignty.
[B] LIMITATIONS ON THE RIGHT TO SELF-DEFENCE: “IF AN ARMED ATTACK OCCURS”
In assessing the lawfulness of the United States’ strike on Soleimani and the subsequent Iranian response, it is first necessary to evaluate adherence to the key requirement of self-defence as provided for under Article 51 of the Charter: the existence of an armed attack.[21] As outlined in the Armed Activities case, Article 51 “does not allow the use of force by a State to protect perceived security interests beyond these parameters”.[22] However, the flexible language of this provision has generated considerable debate regarding the required thresholds for an act to be considered an “armed attack”.[23] This tension has been further exacerbated by state practice attempting to expand this provision to include attacks which have not yet occured- referred to as preemptive self defence- on the basis that states are unwilling or unable to mitigate imminent security threats.[24] The following section will address these issues, analysing the extent to which the actions of the United States and Iran were justifiable acts of self-defence in response to armed attacks, applying both broad and more restrictive interpretations to the Charter’s requirement that self-defence may only be invoked if an “armed attack” occurs.
(1) Justifications for the use of force
The dilemmas which arise from attempting to determine the criteria for an “armed attack” sit at the heart of assessments of the lawfulness of these uses of force. Iran and the United States justified their measures on two ill-defined grounds: the principle of imminence and the “accumulation of events” doctrine. Whilst several scholars consider the expansion of the term “armed attack” to include these grounds for self-defence to be impermissible,[25] there is a broad acceptance that preemptive acts of self-defence taken to avert imminent attacks is legal under Article 51 of the Charter.[26] With regards to the notion of an “accumulation of events”, there is also general support for the argument that a series of events can constitute an armed attack.[27] However, even if accepting the permissibility of these principles, lack of clarity regarding their criteria complicates assessments of legality. Taking these contentions into account, this section will provide an analysis of the extent to which the strikes on Soleimani and the Ayn Al Asad airbase can be considered to be responses to an “imminent” threat or a “series of armed attacks”. Further analysis will then be undertaken to determine the extent to which these “armed attacks” justified the violation of Iraqi territorial sovereignty.
a) Pre-emptive self-defence: the notion of “imminence”
There is a broad acceptance that the pre-emptive use of force in self-defence must be restricted to ‘“imminent threats”.[28] This principle was referenced by the Trump administration, which stated that the strike on Solemani was aimed at preventing “imminent attacks” on United States diplomats and military personnel.[29] However, the lack of explicit criteria for this provision has generated contention pertaining to the required thresholds for imminence. Firstly, scholars of the liberal school of thought contends that measures of self-defence to prevent an imminent attack are permissible if they meet the standard laid out in the Caroline formulation that a threat must be “instant, overwhelming and leaving no choice of means, no moment of deliberation”.[30] Secondly, expansionist scholars contend that a broader understanding of the right to preemptive self-defence must be utilised to “reflect the capabilities and aims of terrorist groups and rogue states”.[31] Recognising that Iran did not provide the justification of an “imminent threat” for its response[32] and it is not admissible “to ascribe to States legal views which they do not themselves formulate”,[33] this section will draw upon both schools of thought to determine whether the United States strike on Soleimani meets the criteria to invoke the right to preemptive self-defence.
Rooted in the liberal interpretation that states are only allowed to resort to the use of force in pre-emptive self-defence when the threat is real and imminent,[34] several scholars have argued that as the Trump administration failed to provide evidence in support of a tangible threat, the strike on Soleimani was unlawful under Article 51.[35] Drawing upon the ICJ’s judgement in Gabcikovo-Nagymaros that “‘imminent’ is synonymous with ‘immediacy’ or ‘proximity’ and goes far beyond the concept of possibility”,[36] it may be reasoned that “self-defence cannot be exercised merely on the ground of speculations”.[37] On this basis, Milanovic has argued that the lack of facts provided by the Trump administration pertaining to the perceived imminent threat “casts serious doubts on whether the various factual predicates for lawful self-defence could be met”.[38] This argument is supported by Callamard, who, drawing upon the Caroline formulation,[39] notes that the United States failed to provide any evidence of a threat “which left no choice of means, and no moment of deliberation”.[40] Consequently, as the United States’s expanded interpretation of the right to self-defence was utilised to counter an unspecified attack which it has not disclosed tangible evidence of, it may be reasoned that the attack constituted “an unlawful exercise of preventive self-defence”.[41]
However, expansionist interpretations of self-defence recognise that there is an argument that the United States’ justification of the targeted strike as self-defence in response to an “imminent threat” is permissible if Solemani was in fact planning attacks on Americans. As Sofaer has noted, given the difficulty of determining the imminence of a threat from ‘rogue’ states which utilise “weapons that can be easily concealed, delivered covertly, and used without warning”[42]; the traditional narrow interpretation is arguably not applicable to such security threats.[43] This argument appears to be supported by Chatham House, which proposes that an assessment of imminence should include whether the state is in possession of weapons of mass destruction and if the threat is likely to come without warning.[44] Given the widely acknowledged military capability of Iran and that it is considered to be a ‘rogue’ state by the United States[45], it may therefore be conceivable that Soleimani did pose an imminent threat in which “any further delay in countering [would] result in the inability of the defending state to effectively defend against or avert”.[46] However, the lack of evidence provided by the United States in support of this argument renders it difficult to make a conclusive judgement in favour of the lawfulness of the strike on this basis.
b) The accumulation of events doctrine
Whilst the legality of the strike on Soleimani on the basis of an ‘imminent threat’ is disputable, both states justified their uses of force on the basis that they had been “subjected to a series of attacks”.[47] As recognised by the Court in the Armed Activities case, there is considerable support that the ‘accumulation of events’ does affect the possibility of exercising the right to self-defence”,[48] raising the possibility that both states could potentially draw upon this doctrine to claim self-defence.[49] However, its applicability to the United State’s use of force is arguably limited by the lack of evidence that the series of attacks were in fact ongoing. Whilst in such cases it is difficult to determine “whether a series of attacks is continuing or whether it has come to an end with the latest attack”,[50] it may be argued that due to the “series of attacks” being intersected with acts of self-defence by the United States, the drone strike cannot be reasonably claimed as an act of self-defence on a cumulative basis.[51] This perspective is reinforced by Haque, who contends that “if one attack is clearly over, then the legal ‘clock’ resets”.[52] For example, as recognised by Ferro, “the United States already responded militarily on 29 December, thereby exhausting the possibility of again invoking the [accumulation of events] doctrine a few days later”.[53] Similarly, in its letter to the Security Council Iran recognised that in June 2019, “the armed forces of the Islamic Republic of Iran took measured and proportionate military action in self-defence…when a United States unmanned aircraft system, despite repeated radio warnings, violated Iranian airspace”.[54] Thus, the prior acts of self-defence carried out by both states raises considerable doubts as to the applicability of the “accumulation of events” doctrine to either uses of force.
(2) Violations of Iraqi sovereignty?
Given that both uses of armed force were carried out within Iraqi territory, it is also necessary to assess the permissibility of the use of force within a third state. With reference to the statement in article 2(4) of the United Nations Charter that “all Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state”,[55] it is widely recognised that states cannot take measures within the territory of another state without consent.[56] However, as noted by The International Law Commission, there are some circumstances which negate the illegality of attacks conducted on a foreign territory, including acts of self-defence against a State “responsible for its internationally wrongful acts.”[57] Recognising that consent was not provided for either strikes,[58] this essay will assess the extent to which the actions of both states were consistent with international law on the basis of the armed attacks being attributable to Iraq, or Iraq’s unwillingness to eliminate an imminent threat.
a) State responsibility
It is widely recognised that states may use force against a state which is deemed responsible for the armed attacks of a non-state actor. Whilst there are issues in determining state responsibility,[59] clarity can be ascertained from the United Nations General Assembly resolution on the “Definition of Aggression”, which finds that attacks in which that state had a “substantial involvement” constitute acts of aggression by the supporting state.[60] Further clarity is provided in the Nicaragua case, where the Court determined that the supplying of arms by a state to an armed group that then conducts armed attacks on a neighbour does not meet the threshold of “substantial involvement”, and thus does not invoke the rights of self defence.[61] However, the targets in this case were not non-state actors, but instead state actors and military personnel of Iran and the United States. With this in mind, and given that that both states attributed the “armed attacks” to one another and not to Iraq, it may be reasoned that the United States and Iran did not understand Iraq to be responsible for the attacks, meaning that the justification of self-defence was not available for either state to legally violate Iraq’s territorial sovereignty.
b) Unwilling or unable?
As Iran and the United States did not appear to have the right to violate Iraq’s territorial sovereignty on the basis of state responsibility, it is necessary to assess the extent to which the acts of force were permissible under the “unwilling or unable” doctrine. The United States government is of the view that it can legally use force in states which are “unwilling or unable” to take action to eliminate what it perceives to be imminent threats.[62] Despite the legality of this doctrine being heavily contested and international law providing little guidance to determine when it may be invoked,[63] some scholars have drawn upon the Bethlehem Principles to argue that considering Kata’ib Hezbollah’s close ties to Iraq, no consultation or evidence was required to determine that Iraq was unwilling to address the threat posed to United States personnel.[64] With reference to Principle 12, given that there is a “strong, reasonable, and objective basis” that obtaining consent would increase the risk that Iraq would alert the target and render the use of force ineffective[65], the United States was arguably entitled to operate under the assumption that Iraq would be unwilling to take action or provide consent.[66] Thus, it may be reasoned that the close ties between Iraq and Solemani “fundamentally transformed the legal nature of the situation”,[67] entitling the United States to legally take measures within Iraqi territory without concrete proof of Iraq’s position.
However, given that the Bethlehem Principles do not provide concrete legal guidance as to how determinations of unwillingness are to be made, assumptions of legality on this basis are weak.[68] Several scholars have argued that contrary to the interpretations of Bethlehem, it is necessary to provide substantial evidence to demonstrate a state’s unwillingness. For example, Schmitt asserts that “the victim state must first ask the [host] state to meet its legal duty…only if it is unable to do so.. the victim state may act militarily in self-defense”.[69] This interpretation is mirrored by Callamard, who notes that “given the absence of consultation prior to the drone strike…there was no evidence that Iraq was unwilling or unable to cooperate”.[70] In fact, it may be reasoned that the lack of evidence and consultation resulted in a misjudgement of Iraq’s willingness to mitigate the threat, as demonstrated by reports that in June 2020 Iraqi forces arrested Kata’ib Hezbollah operatives to pre-empt an attack on United States targets in Baghdad.[71] Thus, even if accepting the lawfulness of the doctrine, given the lack of consultation by both states prior to the use of force on Iraqi territory,[72] it may be reasoned that there is a lack of the required evidence for Iraq’s unwillingness to be used as a legal basis for self-defence for either state.
[C] LIMITATIONS ON THE USE OF FORCE: A PROPORTIONAL AND NECESSARY RESPONSE?
In order to assess the lawfulness of the strike on Soleimani and the subsequent Iranian response, it is also necessary to determine the extent to which the force used was in both cases proportionate and necessary. Although these principles are not mentioned in the Charter, the ICJ has established that it is a principle of customary international law that use of force in self-defence must be “proportional to the armed attack and necessary to respond to it”[73], and thus failure to meet either test would render the use of force unlawful.[74] These requirements are of particular importance to ensuring that the use of force is used for defensive rather than offensive purposes, and thus limited to achieving the objective of ending or repelling illegal armed attacks.[75] Recognising that even if the threats posed were recognised to be armed attacks, the force used in response must still have been necessary and reasonable in the circumstances of the case to comply with international law, this section will assess the extent to which it was permissible to use defensive force in response to the attacks, and whether the extent of the force used was justifiable.
(1) Necessity
To meet the requirement of necessity, states must only use force in self-defence when it is necessary to bring an attack to an end, or to avert an imminent attack.[76] Whilst the ICJ’s evaluation of necessity has been limited, guidance may be found in the Oil Platforms case where the Court directly connected the nature of the target to the necessity of the response.[77] Applying this criteria to the cases at hand, an argument in favour of the necessity of the targeted strike can be drawn from statements by the Trump administration that killing Soleimani was required due to his instrumental role in the planning of a future attack.[78] As noted by Milanovic, “considering KH’s close ties to Iraq, their open pledge of loyalty to Iran and the regular meetings with Soleimani, there may be evidence that Iran, through its Quds forces, planned, ordered and controlled the KH attacks on US forces in Iraq”.[79] Evidence in support of this argument can be found in reports that in the months following the targeted attack, Kata’ib Hezbollah did in fact agree to ceasefire operations against United States interests in Iraq.[80] On the basis of a determination as to whether the target was required to bring an attack to an end, it may be reasoned that in this case, striking the key personnel of what the United States designates as a terrorist group may have in fact been necessary.[81]
However, this argument is weakened by the recognition that whilst it is plausible that killing Soleimani did have a tangible impact on the prevention of future attacks, this is purely conjecture given that the United States has offered no evidence in support of this.[82] Further doubt on the necessity of the strike is generated by reports that United States officials were aware that Iran “had not yet approved any plans by the general for an attack”.[83] Operating under the assumption that these reports are correct, there is little evidence that the strike on Soleimani was necessary to avert an imminent attack. This is further supported by a statement by the Army General Milley that “violent plots by Soleimani might still happen despite his death”[84]. Thus, given the reasonable doubt that the strike on Soleimani was necessary to avert an imminent attack, it may be reasoned that the necessity of the attack by the United States is questionable. A similar argument can be applied to the Iranian missile strike; it is difficult to argue that an attack on an air base used to train Iraqi soldiers would be necessary to bring a “series of attacks” by the United States to an end, and support for this can be found in statements that indicated that the attack was in fact an act of “fierce revenge”.[85] Thus, it may be argued that the principle of necessity was not met by either state given the lack of evidence that there were no alternatives other than the use of force on the specific targets to bring attacks to an end.[86]
Further arguments that the United States’ and Iranian attacks failed to meet this requirement are rooted in the acknowledgement that as they were carried out in Iraqi territory, the necessity of carrying out the attacks in this location must also be demonstrated.[87] As recognised by Milanovic, “the US would need to demonstrate that it had to strike at Soleimani when and where it did… and that it could not wait to strike at Soleimani elsewhere”.[88] Given that the immediacy of the attack is disputable, it is questionable that the United States’ strike had to take place in Iraq during the days that Soleimani was visiting. Furthermore, it was not suggested that Iraq was the location of an imminent attack, and Soleimani was liable to international travel which suggests that he could be targeted anywhere else in the world.[89] On this basis, Callamard notes that there is little evidence to suggest that the condition of necessity was met.[90] With regards to Iran, there is also little basis for the argument that it was necessary to strike the Ain Al Asad air base in Iraq, as attacks would not be prevented by such a measure given that the prior use of force had been carried out with drones which are not constrained to singular locations. Thus, it may be determined that neither military attacks were necessary to either put an end to a series of attacks or prevent an imminent threat.
(2) Proportionality
Whereas necessity determines whether armed force may be used to respond to an actual or imminent armed attack, proportionality requires that the defensive response be no more than necessary to defeat the armed attack and remove the threat of attacks in the future.[91] While proportionality is accepted as a requirement for self-defence under customary international law, no consensus has developed among legal scholars with regards to its exact criteria.[92] Whilst some scholars are of the belief that defensive action must be equivalent with the first use of force,[93] most argue that the test for proportionality comes down to whether the defending state used the amount of force which was proportional to repelling the attack.[94] Accordingly, for the purposes of assessing the proportionality of the cases at hand, a mixed model of proportionality which draws upon both tests will be applied.
With regards to a quantitative assessment of whether the armed attacks and the defence were “commensurate in terms of casualties and damage incurred”,[95] whilst it is difficult to determine what either state perceives to be the “first attack”, it may be reasoned that both uses of force were disproportionate in relation to all prior attacks identified. In its letter to the Security Council, the most substantial attacks identified by the United States were sustained by unmanned aircraft and aerial systems, in addition to the siege upon the United States embassy in Baghdad in which there were no casualties.[96] With the scale of these attacks in mind, the United States drone strike which resulted in the death of ten individuals, including one of the most powerful men in Iran,[97] may be interpreted as a disproportionate response in terms of casualties and damage incurred. In Iran’s letter to the Security Council, two major prior attacks pertaining to violations of Iranian airspace by unmanned aircraft systems were identified.[98] Even if the ‘first attack’ identified were the strike upon Soleimani, the missile attack which resulted in severe brain damage of over one hundred U.S military personnel[99] is clearly unproportionate in terms of scale of damage when compared to the prior attacks incurred.
Under the assumption that the defending state is entitled to engage in the extent of force required to repel an armed attack,[100] it may be argued that the United States’s measures were in fact proportional given that previous lighter approaches had failed to successfully avert future threats. For example, Ferro highlighted that on 29 December 2019 the United States bombed bases of the Kata’ib Hezbollah militia to reduce “KH’s ability to launch additional attacks against United States personnel”, but this was proved to be ineffective given the attacks by Kata’ib Hezbollah on United States personnel in the storming of the embassy in Baghdad a few days later.[101] Thus, given the potential capacity of the future attacks given that the United States recognises Iran as a “rogue” state, it may be reasoned that the extent of the measures taken by the United States can be deemed an appropriate pursuit of the military defeat of the aggressor. However, this argument is once again weakened by the United States failing to disclose knowledge of a threat from Solemani that is tangible, immediate and to the United States in particular; this renders assessments of the proportionality of the strike difficult given the lack of evidence provided with regards to what it was countering.
[D] AN ASSESSMENT OF LAWFULNESS UNDER JUS AD BELLUM
(1) Concluding remarks on self-defence
As recognised by Dinstein, under no circumstances can the use of force by both parties to a conflict be lawful under the provisions of jus ad bellum simultaneously.[102] However, following a determination of the compliance of the cases at hand with Article 51 and relevant customary international law, this essay finds that there is a lack of credible evidence that either state meets the criteria for their uses of force to be considered lawful acts of self-defence. Firstly, with regards to both the killing of Soleimani and Iran’s missile strike, there is a strong argument that neither strikes meet the requirements that acts of self-defence must be in response to an armed attack, even under the broadest of interpretations. Secondly, the lack of clarity surrounding the purported threats presents significant difficulties in determining the lawfulness of the strike with regards to the requirements of necessity and proportionality in both cases. On these bases, this essay finds that both the United States strike on Soleimani and the subsequent Iranian missile attack clearly demonstrate a lack of “fit” with the requirements of self-defence under both the Charter and customary law.
Additionally, a clearer argument can be established with regards to the illegality of the United States and Iranian uses of force given that both attacks were carried out in the territory of a third state. It may be reasoned that the lack of reasonable grounds for breaching state’s sovereignty to carry out the attacks on Iraqi territory as opposed to within the territory of the parties to the dispute clearly results in a failure to meet the requirements of self-defence pertaining to the existence of an armed attack or threat attributable to a failing on Iraq’s part, and a necessary use of force. On this basis, both the United States strike on Soleimani and the Iranian missile strike may be considered to be unlawful uses of force under the jus ad bellum framework, constituting an impermissible violation of Iraqi territorial sovereignty under the United Nations Charter.
(2) A reasonable armed reprisal?
As a result of the failure of the cases at hand to meet the requirements for self-defence, it is necessary to assess whether the use of force by Iran and the United States can be considered to be a “reasonable” armed reprisal.[103] Broadly defined as a breach of international law in response to a violation by another state in order to enforce compliance,[104] whereas self-defence is directed towards establishing future state security, reprisals aim to punish past behaviour.[105] Whilst generally recognised as illegal under both the Charter and customary international law,[106] practice of the Security Council suggests that “while reprisals remain de jure illegal, they have gained de facto acceptance”.[107] Thus, assessments as to whether the cases at hand fall within the “rubric” of self-defence or armed reprisal, whilst not necessarily generating different outcomes in terms of lawfulness, may give rise to differing degrees of acceptability amongst the international community. However, as it is generally accepted that armed reprisals can only be invoked against the actual wrongdoing state and not against third parties,[108] it is evident that, due to the measures being carried out in Iraq, the hostilities carried out by both states fail to “fit” within the scope of both self-defence and a reasonable armed reprisal.
[E] CONCLUSION
This paper has highlighted the failures of both the United States’ and Iran’s use of armed force to meet the requirements to be considered lawful under the jus ad bellum framework. This is due to a lack of credible evidence that Iraq was either responsible for an imminent attack, or unwilling to address a threat upon either the United States or Iran within its territory, which in turn gave rise to a lack of necessity of the strikes. The findings of this study provide an initial understanding as to why the cases at hand appear not to fall within even the broadest interpretations of the right to self-defence or a “reasonable” armed reprisal, as recognised by Callamard, “even the legality of a strike under Article 51 of the Charter does not preclude its wrongfulness under international humanitarian or human rights law”.[109] Consequently, further research is necessary in order to determine whether (1) the situation amounts to an international armed conflict; (2) the targeted killing fulfilled the requirements of necessity and last resort under international human rights law, and; (3) the targets were considered to be legitimate under jus in bello, and the use of force was governed by the principles of distinction, proportionality and precaution.
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*LLM International Law student at the University of Edinburgh
[1] W Martel “United States Drone Strike in Iraq Kills Iranian Military Leader Qasem Soleimani” (2020) 313 AJIL 1
[2] M Nichols “At U.N., United States justifies killing Iranian commander as self-defense” Reuters (London, 9 Jan 2020)
[3] AJIL Contemporary Practice of the United States, “Trump Administration’s Iran Policies Raise Questions About the Executive’s Authority to Use Force Against Iran” (2019) AJIL 845
[4] United States Department of Defense Statement by the Department of Defense (Jan 2 2020)
[5] UNSC Letter dated 8 January 2020 from the United States Ambassador to the UN addressed to the Secretary-General (2020)
[6] Ibi
[7] Ibid
[8] J Moussa “Can jus ad bellum override jus in bello? Reaffirming the separation of the two bodies of law” (2008) 90 IRRC 372 at 965
[9] At M Bothe “Terrorism and the Legality of Pre-emptive force” (2003) 40 EJIL 2 at 227-240
[10] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 60
[11] L Loveluck “Trump says Iranian military leader was killed by drone strike ‘to stop a war,’ warns Iran not to retaliate’” The Washington Post (Washington, 4 Jan 2020)
[12] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 31
[13] J Moussa “Can jus ad bellum override jus in bello? Reaffirming the separation of the two bodies of law” (2008) 90 IRRC 372 at 963
[14] Charter of the United Nations 1945)1 UNTS XVI article 2(4)
[15] Nicaragua v. United States of America (Merits, Judgement) [1986] ICJ Rep 14 ICGJ 112 para. 69
[16] Charter of the United Nations 1945)1 UNTS XVI article 51
[17] J Paust “Use of Armed Force Against Terrorists in Afghanistan, Iraq and Beyond” (2002) 35 CILJ 3 at 538
[18] D Kretzmer “Inherent Right to Self-Defence and Proportionality in Jus Ad Bellum” (2013) 24 EJIL 1 at 262
[19] Charter of the United Nations 1945)1 UNTS XVI article 51
[20] Request for Advisory Opinion by the General Assembly of the United Nations) [1996] ICJ Rep 226 ICGJ 205, para. 41
[21] Charter of the United Nations 1945) 1 UNTS XVI Article 51
[22] Democratic Republic of the Congo v. Rwanda [2005] ICJ Rep I68 ICGJ 31 para. 148
[23] At Y Dinstein, War, Aggression and Self-Defence (2001) 159-191
[24] L Van den hole “Anticipatory Self Defence Under International Law” (2003) 19 AUIL Rev 1 at 74
[25] At E Erikson Legitimate Use of Military Force Against State-Sponsored International Terrorism (1989) 217
[26] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 52
[27] Democratic Republic of the Congo v. Rwanda [2005] ICJ Rep I68 ICGJ 31 para. 132
[28] At L Ferro “Killing Qasem Soleimani: International Lawyers Divided and Conquered” (2021) 53 CWRJ
[29] A Chung “United States ‘self-defense’ argument for killing for killing Soleimani meets skepticism” Reuters (4 January 2020)
[30] The Caroline Case [1840] BFSP 1137 (Sourced from D.J Harris Cases and Materials on International Law 1976)
[31] A Sofaer “On the Necessity of Pre-emption” (2003) 14 EJIL 2 at 221
[32] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 61(b)
[33] Nicaragua v. United States of America (Merits, Judgement) [1986] ICJ Rep 14 ICGJ 112 para. 226
[34] Ibid 268
[35] At M Milanovic “The Soleimani Strike and Self-defence against an Imminent Armed Attack” (2020) EJIL 1
[36] Hungary v Slovakia Judgement, Merits [1997] ICJ Rep 7 ICGJ 66 para. 54
[37] Y Dinstein, War, Aggression and Self-Defence (2001) 235
[38] At M Milanovic, “The Soleimani Strike and Self-defence against an Imminent Armed Attack” EJIL (2020) 1
[39] The Caroline Case [1840] BFSP 1137 (Sourced from D.J. Harris Cases and Materials on International Law 1976)
[40] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 52
[41] At L Ferro “Killing Qasem Soleimani: International Lawyers Divided and Conquered” (2021) 53 CWRJ 1
[42] Ibid
[43] A Sofaer “On the Necessity of Pre-emption” (2003) 14 EJIL 2 at 209
[44] Chatham House “Principles of International Law on the Use of Force by States in Self-Defence” (2005) ILPWP para. 4
[45] J.R. Bolton “Remarks to the Conference of the Institute for Foreign Policy Analysis and the Fletcher School’s International Security Studies Program” (2003)
[46] E Wilmshurst “Anticipatory self-defence against terrorists” in L Herik (eds), Counter-Terrorism Strategies in a Fragmented International Legal Order (2013) 361
[47] UNSC “Letter dated 29 January 2020 from the Iranian Ambassador to the UN addressed to the Secretary-General” (2020); UNSC “Letter dated 8 January 2020 from the United States Ambassador to the UN addressed to the Secretary-General” (2020)
[48] Democratic Republic of the Congo v. Rwanda [2005] ICJ Rep I68 ICGJ 31 para. 132
[49] F Talmon, “The United States Killing of Iranian General Qasem Soleimani: Of Wrong Trees and Red Herrings, and Why the Killing May be Lawful after All” (2002) Bonn Research Papers on Int’l Law 18 at 7
[50] Ibid
[51] At L Ferro “Killing Qasem Soleimani: International Lawyers Divided and Conquered” (2021) 53 CWRJ at 1
[52] At A Haque “United States Legal Defense of the Soleimani Strike at the United Nations: A Critical Assessment” (2020) JS 1
[53] L Ferro “Killing Qasem Soleimani: International Lawyers Divided and Conquered” (2021) 53 CWRJ at 1
[54] UNSC “Letter dated 29 January 2020 from the Iranian Ambassador to the UN addressed to the Secretary-General” (2020)
[55] Charter of the United Nations 1945 1 UNTS XVI, article 2(4)
[56] N Duhem “The Legitimacy of Anticipatory Self-Defence in Combating Transnational Terrorism” (2020) Universiteit Ghent at para. 56
[57] U.N. International Law Commission “Commentary to Article 21: Responsibility of States for Internationally Wrongful Acts” Supplement No. 10 A/56/10 (2001) para. 8
[58] A Ibrahim “Iraqis denounce Iran missiles as ‘violation of sovereignty’’ Aljazeera (Doha, 8 Jan 2020)
[59] C Martin “Going Medieval: Targeted Killing, Self-Defense and the Jus Ad Bellum Regime” in C Finkelstein Targeted Killings: Law and Morality in an Asymmetrical World (2011)
[60] UN General Assembly resolution Definition of Aggression (UN Doc. A/RES/3313 1974), article 3(g)
[61] Nicaragua v. United States of America (Merits, Judgement) [1986] ICJ Rep 14 ICGJ 112
[62] Stimson ‘Recommendations and Report of the United States Task Force on US Drone Policy’ (2014) 10
[63] Chatham House ‘Principles of International Law on the Use of Force by States in Self-Defence’ (2005) ILP WP for an argument in favour of its necessity post 9/11; At Stimson, ‘Recommendations and Report of the United States Task Force on US Drone Policy’ (2014) for an outline of it opening the door for misuse.
[64] At P Labuda “The Killing of Soleimani, the Use of Force against Iraq and Overlooked Jus Ad Bellum Question”’ EJIL (2020)
[65] D Bethlehem “Principles relevant to the scope of a state’s right of self-defense against an imminent or actual armed attack by nonstate actors” (2012) AJIL 106 principle 12
[66] Ibid, principle 11
[67] United States of America v Iran [1981] ICJ Rep 3 ICGJ 124 para. 74
[68] C Martin“Challenging and Refining the ‘Unwilling or Unable’ Doctrine” (2019) 52 SSRN 230
[69] M Schmitt Drone Attacks under the Jus ad Bellum and Jus in Bello: Clearing the ‘Fog of Law (2010) 9
[70] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 78
[71] Center for International Security and Cooperation ‘Kata’ib Hezbollah’ (2021) FSI Mapping Militants CISAC
[72] A Ibrahim “Iraqis denounce Iran missiles as ‘violation of sovereignty’’ Aljazeera (Doha, 8 Jan 2020)
[73] Request for Advisory Opinion by the General Assembly of the United Nations [1996] ICJ Rep 226 ICGJ 205, para. 41
[74] J Gardam Necessity, Proportionality and the Use of Force by States ( 2004) 16
[75] N Duhem “The Legitimacy of Anticipatory Self-Defence in Combating Transnational Terrorism”, Universiteit Ghent (2012) 7
[76] Chatham House “Principles of International Law on the Use of Force by States in Self-Defence” (2005) ILP WP 7
[77] Islamic Republic of Iran v. United States of America [2003] ICJ Rep 161 ICGJ 74 para. 51
[78] United States Department of Defense “Statement by the Department of Defense” (Jan 2 2020)
[79] M Milanovic“The Soleimani Strike and Self-defence against an Imminent Armed Attack”(2020) EJIL 1
[80] J Davison “Iraqi militias say they have halted anti-United States attacks” Reuters (London, 11 October 2020)
[81] United States Department of State “Terrorist Designations and State Sponsors of Terrorism: Foreign Terrorist Organisations” (Feb 7 2009)
[82] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 61(b)
[83] H Cooper “As Tensions with Iran Escalated, Trump Opted for the Most Extreme Measure” New York Times (4 Jan 2020)
[84] M Hosenball “Trump says Soleimani plotted ‘imminent’ attacks, but critics question just how soon” Reuters (London, 3 Jan 2020)
[85] A Rubin “Iran Fires on United States Forces at 2 Bases in Iraq, Calling it ‘Fierce Revenge” New York Times (London, 7 Jan 2020)
[86] O Schachter “Self-Defense and the Rule of Law”(1989) 83 AJIL 267
[87] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 68
[88] M Milanovic“The Soleimani Strike and Self-defence against an Imminent Armed Attack” (2020) EJIL 1
[89] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 73
[90] Ibid para. 61(a)
[91] A Deeks “Unwilling or Unable: Toward a Normative Framework for Self-Defense” (2020) 52 Va. J. Int’l L 494
[92] S Etezazian “The nature of the self-defence proportionality requirement” (2016) 3 Journal on the Use of Force and Int’l Law 261
[93] J Gardam Necessity, Proportionality and the Use of Force by States (2004) 17
[94] Y Dinstein War, Aggression and Self-Defence (2001) 743
[95] L Van den Herik “Counter-Terrorism Strategies in a Fragmented International Legal Order” (2013) 389
[96] UNSC, “Letter dated 8 January 2020 from the U.S Ambassador to the UN addressed to the Secretary-General” (2020)
[97] W Martel “United States Drone Strike in Iraq Kills Iranian Military Leader Qasem Soleimani” (2020) 114 AJIL 313
[98] UNSC “Letter dated 29 January 2020 from the Iranian Ambassador to the UN addressed to the Secretary-General” (2020)
[99] W Martel “United States Drone Strike in Iraq Kills Iranian Military Leader Qasem Soleimani” (2020) 114 AJIL 313
[100] Y Dinstein War, Aggression and Self-Defence (2001) 743
[101] L Ferro “Killing Qasem Soleimani: International Lawyers Divided and Conquered” (2021) 53 CWRJ 1
[102] Y Dinstein War Aggression and Self-Defence (2001) 743
[103] A Haque “United States Legal Defense of the Soleimani Strike at the United Nations: A Critical Assessment”(2020) JS 1
[104] M Weller The Oxford Handbook of the Use of Force in International Law (2017) 881
[105] B Levenfeld “Israel’s Counter-Fedayeen Tactics in Lebanon: Self-defense and Reprisal Under Modern International Law” (1982) 21 Colum. J. Transnat’l L 37
[106] N Rontzitti “The expanding law of self-defence” (2006) 11 JSCL 354
[107] D Bowett “Reprisals Involving Recourse to Armed Force” (2017) 66 AJIL at 1-36
[108] U.N. International Law Commission “Commentary to Article 21: Responsibility of States for Internationally Wrongful Acts” Supplement No. 10 A/56/10 2001 article 14
[109] HRC Targeted killings through armed drones and the case of Iranian General Quassem Soleimani (UN Doc. A/HRC/44/38 2020) para. 31