On Jan. 3, a targeted drone strike near Baghdad International Airport killed Iranian Maj. Gen. Qassem Soleimani. Killed along with him was Abu Mahdi al-Muhandis, deputy commander of Iraq’s Popular Mobilization Forces (PMFs), or Hashd al-Shaabi, and leader of the Iraqi militia Keta’ib Hezbollah. Reportedly, four other persons were also killed. So, far there has been no official justification for the killing of al-Muhandis, just indirect reference to his role in Iraq, which would tend to show that, along with the other four people, he was not targeted.
A few hours after the strike, the U.S. Department of Defense (DoD) claimed that the U.S. military had taken this “decisive action” against Soleimani at the request of President Donald Trump because “General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region.” The statement went on to refer to the responsibilities of Soleimani and his Quds Force for the deaths of hundreds of American and coalition service members, attacks on coalition bases, and the attacks on the U.S. Embassy in Baghdad. The Pentagon concluded that “This strike was aimed at deterring future Iranian attack plans.”
Subsequently, Trump made a public statement claiming that the strike “aimed at stopping a war, not starting one.” Since then, U.S. officials have shifted the logic of their justification from the initial angle of retaliation and vague references to possible future attacks, to focus on the threat of “imminent” attack.
In its response, Iran has promised “vigorous revenge” for the U.S. attack. The US has then engaged in a belligerent tit-for-tat narrative including a promise to target Iranian cultural sites, which would itself be a violation of international humanitarian law (IHL).
Among commentators, much of the focus has been on the killing’s implications for peace in the Middle East and globally; on whether it served U.S. standing and interests, and on the political and military reasoning behind the decision to target Soleimani.
However, to date, the legality of the strike under international law, the focus of this article, has received considerably less attention. Analyzing the killing of Soleimani from an international law standpoint matters a great deal. It is, in my view, the main framework through which the extra territorial use of force ought to be assessed, whether the U.S. considers itself bound by it or not. Reasserting the primacy of international law in such times of crisis is a solemn and foundational duty of and for the international community.
My point of departure for analyzing the strike follows that of former UN Special Rapporteur Christof Heyns, who wrote in a 2013 report to the UN that for a particular drone strike to be lawful, it must satisfy the legal requirements under all applicable international legal regimes, namely: the law regulating inter-state use of force (jus ad bellum); international humanitarian law (jus in bello) and international human rights law (IHRL). It is also my view that on its own jus ad bellum is not sufficient to guide the use of force extra territorially and that other legal frameworks and principles apply. Such a position is backed up by the International Law Commission (ILC) Draft Articles on State Responsibility, which state that:
“As to obligations under international humanitarian law and in relation to non-derogable human rights provisions, self-defense does not preclude the wrongfulness of conduct.”
In my initial assessment of the strike, before the U.S. claimed responsibility, I focused on jus ad bellum and IHRL and argued that outside the context of active hostilities, the use of drones for targeted killing is almost never likely to be legal. Here, I will briefly present the requirements under both legal frameworks and then turn my attention to IHL and seek to explain why I did not, and do not, assume that international humanitarian law necessarily applied to this particular strike.
Jus ad bellum: According to Article 51 of the UN Charter and customary international law, a State may invoke self-defense, including more controversially, anticipatory self-defense, to justify its use of force in another State’s territory when an armed attack, having reached a certain threshold of gravity, occurs or is imminent. International jurisprudence and State practices suggest that self-defense cannot be invoked to prevent a threat from arising nor can it be invoked in retaliation for past events. It can be invoked only against a threat that is already present and which is “instant, overwhelming and leaving no choice of means, no moment of deliberation.” In addition to imminence, the targeted killing of Soleimani must also meet two other requirements under jus ad bellum: necessity and proportionality. Necessity demands that there would be no other alternative to the use of military force. Under the test of proportionality, force must be used only to the extent necessary. The US would thus have to prove that killing Soleimani would have prevented an imminent attack and that it was the only way of preventing such attack.
Following the initial DoD statement, the Trump and other officials have sought to insist that an attack under the direction of Soleimani was imminent, prompting the Washington Post to state that “imminent” is the key word in U.S. justifications for the killing of an Iranian general.
However, the few details made publicly available thus far do not establish a factual basis for the claim that any attacks were imminent, let alone that Soleimani was key to their implementation. On Jan. 5, the Iraqi prime minister stated that, to the contrary, General Soleimani had come to Iraq seeking to de-escalate tensions with the U.S. and had asked the Iraqi government to act as a mediator for this purpose, raising further doubts as to imminence of one or several “armed attacks.”
It is also worth emphasizing that if this was self-defense (executed preemptively), then the U.S. should have already informed the UN Security Council. Article 51 of the UN Charter imposes such an obligation immediately after the self-defense act. This has not (yet) happened, another factor calling into question the legality of the strike.
International human rights law (IHRL): As a general principle, the intentional, premeditated killing of an individual would be unlawful under international human rights law. There are exceptions to this rule. For instance, the death penalty is permitted for States that have retained it but only when implemented under very strict conditions. The use of lethal force by State agents may be lawful only as a means of last resort for achieving one legitimate purpose: that of protecting life. Intentionally lethal or potentially lethal force can be used only where strictly necessary to protect against an imminent threat to life. There is an extensive jurisprudence and legal opinions on this matter. But, at a basic level, for the strike against Soleimani to be lawful under IHRL, the U.S. would have to demonstrate that he constituted an imminent threat to the lives of others and that, in order to protect those lives, there was no other option but to use lethal force against him.
Thus far, the justifications advanced by U.S. officials and the U.S. president have focused largely on the past activities of Soleimani and the grave crimes for which he is deemed responsible. And, there certainly seems to be plenty of evidence linking Soleimani to serious human rights violations in Iran, Syria, Iraq and elsewhere. But his past involvement in human rights violations or, indeed, in acts of terror, is not sufficient to make his killing lawful. Further, it is hard to see how the U.S. could explain and justify the killings of five other people traveling with him or standing around the car at the time of the drone strike. Those deaths can only be described as arbitrary deprivations of life under human rights law and should result in State responsibility and individual criminal liability. While international humanitarian law may permit so-called collateral damage, this is not the case under international human rights law or at least not to the same degree. In this particular case, the killings of these other individuals would clearly constitute a violation of U.S. obligations under article 6 of the International Covenant on Civil and Political Rights (ICCPR). In view of the presence of these five individuals, including al-Muhandis decisions should have been made not to proceed with the targeted killing.
Since 1995, the U.S. has argued that obligations under the ICCPR only apply to individuals who are both within the territories of a State party and subject to that State party’s sovereign authority, (although it amended this position with regard to the extra territorial application of the Convention Against Torture in 2014). The U.S. position runs contrary to that of the UN Human Rights Committee (HRC), to the jurisprudence of the International Court of Justice and to State practice – all of which have confirmed that human rights treaties obligations apply to the conduct of States outside national boundaries. In its recent General Comment on the Right to Life (General Comment 36), the HRC has determined that the scope of a State responsibility to protect extends to
“all persons subject to the State’s jurisdiction, that is, all persons over whose enjoyment of the right to life it exercises power or effective control.”
The functional theory of the extraterritorial application of human rights treaties is particularly relevant to the case of a drone strike: The US had power or control over Soleimani’s enjoyment of the right to life. While such arguments may not influence the practice of the U.S., it is important to point out that, in its rejection of its extra territorial human rights obligations, the U.S. is an extreme outlier. The drone strike on Soleimani constituted most probably a violation of U.S. obligations under article 6 of the ICCPR.
International humanitarian law (IHL): In my initial assessment of the targeted killing of Soleimani, I focused solely on the law governing the use of force and on international human rights law as the two applicable bodies of law, rather than on international humanitarian law. Several factors prompted me to do so, all of which pointed to different doctrinal interpretations and tensions and thus to the absence of legal certainty as to the existence of an international armed conflict (IAC).
According to the so-called “first shot” theory, even
“minor skirmishes between the armed forces, be they land, air or naval forces, would spark an international armed conflict and lead to the applicability of humanitarian law. Any unconsented-to military operations by one State in the territory of another State should be interpreted as an armed interference in the latter’s sphere of sovereignty and thus may be an international armed conflict under Article 2(1).”
It could thus be argued that the incidents over the last few weeks such as the Dec. 27 rocket attack in Kirkuk that killed an American contractor or the U.S. airstrike on Dec. 29 against five facilities in Iraq and Syria controlled by Kata’ib Hezbollah, or the U.S. strike itself against Soleimani constituted the beginning of an IAC, thus triggering the applicability of IHL. The “first shot” theory has many benefits, including that of addressing the uncertainty as to what constitutes the beginning of an IAC and as to when humanitarian law must be applied.
To the best of my knowledge, no State, expert commentator or expert body, such as the International Committee of the Red Cross, had identified the escalation of the conflict between the U.S. and Iran as amounting to an international armed conflict. Thus far, the debate as to whether the strike triggered an IAC has been at best discrete and expert-led. It seems somewhat unreasonable to suggest retroactively that an IAC — opposing Iran to the United States — had been waged for several days or weeks prior to the killing in question and that therefore IHL, as opposed to IHRL, constituted the lex specialis during all this time. It is well established that a formal declaration of war is not necessary for an IAC to be in effect. But it is reasonable to expect, at the very least, some open debates then (rather than now) about whether some of the serious incidents over the last month constituted the beginning of an IAC. At the very least, one would have also expected U.S. officials to discuss this possibility and for U.S. democratic institutions to be informed that the incidents had reached the level of an IAC.
There may be good reasons to suggest that the Jan. 3 strike triggered an IAC as opposed to previous incidents. For a start, the earlier events involved proxy fighters on behalf of Iran, rather than Iran’s own military forces. For this reason, the targeting of Soleimani stands out. It may be the first example of the use of a drone strike against members of a State armed forces as opposed to a non-State actor. Secondly, Soleimani was arguably one of the highest-ranking officers within the Iranian military apparatus. Finally, coming in the wake of a multitude of incidents over the last month, it may be said that the U.S. strike finally tipped the scale towards an IAC.
In the context of a non-international armed conflict (NIAC), the prevalent position is that individual drone strikes by themselves are not likely to meet the necessary threshold of violence for a NIAC to come into existence. The ICRC is of the position that such a principle does not apply to an IAC because there is no intensity requirement. The International Law Association’s Committee on the Use of Force differs, arguing that “an armed attack that is not part of intense armed fighting, is not part of an [international] armed conflict.”
The notion that an IAC was in effect either by the time of the strike against Soleimani or as a result of the strike, is further complicated by the fact that the strike, and the attacks that preceded it, took place largely in a third country i.e. Iraq. If the strike (or the incidents before) triggered an armed conflict and IHL between Iran and the U.S., it would seem logical that such a conflict also included Iraq. Indeed, under one IHL doctrine, Iraq’s lack of consent for the strike and, indeed, previous U.S. interventions on its territory, could mean that another IAC was triggered, between the U.S. and Iraq.
These arguments are not meant to completely reject the existence of an IAC. But it seems to me that the conceptual and practical elegance of the first shot theory may mask a number of empirical and doctrinal difficulties. Further, it ought to be accompanied by well thought out analyses of specific incidents by expert or political bodies and warnings that the threshold of an IAC has been breached or is about to be breached. Finally, while there are very good reasons to insist that the U.S. strike should be bound by IHL, there are equally good reasons to insist that it should have been bound by IHRL. Indeed, IHRL offers far stronger protection to civilians. In any case, both IHL and IHRL apply in the context of armed conflict. Absent derogation, human rights obligations continue to apply in time of war or armed conflict.
Finally, it remains questionable whether, under the rules applicable under IHL, the killing of Soleimani would be lawful. While there is no doubt that he constituted a legitimate military target, the U.S. should still demonstrate that the attack was also justified by military necessity i.e. helping in the defeat of the enemy. It would also have to prove that the harm caused to the other five persons, including an Iraqi militia head, was proportionate to the military objective. The information provided over the last three days by U.S. officials involved in the decision-making has certainly not been sufficient to meet these thresholds i.e. has been insufficient to justify the killings under IHL. The burden is naturally on the United States to prove it acted lawfully.
In the immediate aftermath of the killing of Soleimani, naturally enough, much emphasis has been placed on avoiding further violence and on ways to “de-escalate” the tensions. But the questions regarding the lawfulness of the strike should not be ignored.
One country in particular, namely Iraq, should be at the heart of such efforts, given that the strike occurred on its territory. The Iraqi government should be demanding that the UN Secretary-General establish an international inquiry or send a fact-finding mission to address the targeted killing and the other incidents that preceded it, or assist Iraq to conduct such an investigation with international participation. The process of investigation itself may also assist in cooling things down. Under Article 35 of the UN Charter, Iraq (not just Iran) could also bring the “dispute” to the urgent attention of the UN Secretary-General and Security Council.
The UN Secretary-General himself should be bold: He should trigger Article 99 of the UN Charter to bring the matter to the attention of the Security Council given the situation clearly threatens international peace and security. The U.S. will use its veto power to prevent an actual resolution, but the Security Council must at least attempt to face up to its responsibilities. And the UN Secretary-General should place those responsibilities in front of it. If nothing else, the Security Council’s inability to act meaningfully will strengthen arguments for its reform. Nonetheless, it would be irresponsible for the Security Council to be a mere bystander to last week’s U.S. strike or indeed for the acts by Iran-backed proxy forces preceding it.
The targeted killing also reveals a need for stronger technical expertise and more capacity in service of international decision-making bodies, exercised and delivered without fear or favor. Thus far, the UN does not appear to have found its place in this crisis – neither in de-escalation efforts or in resolution of the conflict even though that is its role, and even though it has stewardship over some of the key legal instruments. The vacuum its absence creates will likely be filled by unilateral initiatives of the various parties, auguring poorly for the outcome.
It may be that the UN bodies perceive their actions to be of limited consequence, but there is much more at stake than this moment alone. There are various spaces that ought to be occupied, including those related to the defense, advocacy and application of the rules, to the search for accountability, and in assertion of the primacy of international law. Confronted with the targeted killing of Soleimani, or to others of similar gravity, the UN cannot afford to be absent or impotent, or to have a hand in making itself irrelevant.
I wish to thank Sarah Katherina Stein, Columbia University Law School, for her invaluable research and expertise.
 International Law Commission (ILC), ‘Commentary to art 21, MArticles on Responsibility of States for Wrongful Acts’ (2001)
 I will not address here the debate on whether Article 51 authorises self-defense in anticipation of an attack.