The U.S. killing of Iranian General Qasem Soleimani: of wrong trees and red herrings, and why the killing may be lawful after all

Published: 23 January 2020 Authors: Stefan Talmon and Miriam Heipertz

On 3 January 2020, at about 1am local time, the United States launched a drone strike, killing Iranian Major General Qasem Soleimani and nine members of his entourage near Baghdad International Airport. General Soleimani was the commander of the Quds Force, a military unit of the Islamic Revolutionary Guard Corps (IRGC) of Iran responsible for its foreign operations, supporting non-State actors in neighboring countries, including Shia militias in Iraq. The United States considered Soleimani as the mastermind behind numerous attacks by Iranian proxies against American troops in the Middle East.

The airstrike occurred amid rising military tensions between Washington and Tehran. Since September 2019 there had been 14 attacks by Iran and Iranian-supported militias on U.S. forces. During November and December 2019, on at least five occasions, the Iran-backed militia Kata’ib Hezbollah (KH) attacked bases hosting U.S. forces in Iraq. During a missile attack on 27 December 2019, a U.S. civilian contractor was killed and four American service members were injured. In response, on 29 December 2019 the United States conducted air strikes against the KH in Iraq and Syria, killing at least 25 members of the militia. This in turn prompted supporters of the KH to lay siege to the U.S. embassy on 31 December 2019 and 1 January 2020. Two days later the United States killed General Soleimani in a drone strike.

In a first reaction to the airstrike, the Federal Government spokesperson stated during the regular press conference on 3 January 2020:

“The American action is a response to a whole series of military provocations for which Iran bears responsibility. I am recalling the attacks on the tankers in the Strait of Hormuz and on the Saudi oil installations. We have condemned the attacks on coalition forces in Iraq and the recent attacks on the U.S. embassy.
We, too, view Iran’s regional activities with grave concern. We have reached a dangerous point of escalation. It is imperative now to contribute to de-escalation through moderation and restraint. The regional conflicts can only be resolved through diplomatic channels, and we continue to consult with our allies in that regard.”

The Federal Foreign Office spokesperson added:

“Over the past few weeks, we have repeatedly made it clear that we share the United States’ criticism of Iran’s destructive role in the region. […] In the past week, we repeatedly had to take a stand on the attacks against coalition forces in Iraq and we have also strongly condemned the attacks on the American embassy in Baghdad.”

While the spokesperson declined to provide a legal assessment of the U.S. action, he stressed that the action must not be seen in a vacuum but must be assessed against the background of Iran’s pervious conduct. On 30 December 2019, Germany had condemned “the increasing number of attacks” on Coalition troops in Iraq and squarely put the blame on Iran. Iran’s role in previous attacks on U.S. forces was also highlighted by Federal Foreign Minister Heiko Mass who tweeted:

“The US military operation followed a series of dangerous provocations by Iran. However, this action has not made it easier to reduce tensions. I made this point clearly to @SecPompeo as well.”

Both the United States and Iran were dissatisfied with Germany’s reaction to the strike. U.S. Secretary of State Mike Pompeo lamented the lack of stronger German support in an interview on 4 January 2020:

“Frankly, the Europeans haven’t been as helpful as I wish that they could be. The Brits, the French, the Germans all need to understand that what we did, what the Americans did, saved lives in Europe as well.”

Iran, on the other hand, took issue with the Federal Government spokesperson’s statement that the killing was a response to military provocations by Iran. The spokesperson for the Iranian Foreign Ministry denounced Germany’s position as an “indicator of Berlin’s unawareness of the realities on the ground in the region” and informed Germany that this “will, intentionally or unintentionally, align [Germany] with the United States’ state terrorism.” He declared:

“The Islamic Republic of Iran regards the German government’s stances in support of brutal and unilateral U.S. actions which are against international law as complicity in these actions, and Iran reminds the German government of General Soleimani’s key role in fighting the terrorism of ISIS, whose continued existence would have endangered the lives of countless number of people even in Europe.”

On 5 January 2020, the Iranian Ministry of Foreign Affairs summoned the German chargé d’affaires in the absence of Germany’s ambassador to strongly protest against the “one-sided and unacceptable stances (from German officials) [which] run counter to the traditional cooperation between the two countries (Iran and Germany) and also to the regional stability and security.”

On the same day, the German Chancellor, together with the French President and the British Prime Minister, issued the following statement:

“We have condemned the recent attacks on coalition forces in Iraq and are gravely concerned by the negative role Iran has played in the region, including through the IRGC and the Al-Qods force under the command of General Soleimani.
There is now an urgent need for de-escalation. We call on all parties to exercise utmost restraint and responsibility. The current cycle of violence in Iraq must be stopped.
We specifically call on Iran to refrain from further violent action or proliferation, and urge Iran to reverse all measures inconsistent with the JCPOA. […]
We stand ready to continue our engagement with all sides in order to contribute to defuse tensions and restore stability to the region.”

While Germany acknowledged that the United States responded to military provocations by Iran, unlike other allies of the United States it did not expressly endorse a right to self-defence. When pressed for a legal assessment of the killing, the spokesperson for the Federal Foreign Office stated:

“On the general classification [of the killing of General Soleimani] under international law […]. We have seen the U.S. justification [for the airstrike, namely that General Soleimani is and was an eminent threat] […]. However, we lack information to verify the reasoning. It is clear to us that military use of force can only be the very last resort. For good reason there are strict limits to the use of force in international law, and as Federal Government we want to expressly adhere to this achievement. […] We currently do not have any specific and further information that would allow us to verify the justification under international law.”

This guarded statement, however, did not mean that Germany considered the killing outright unlawful under international law. On the contrary, it seems that Germany considered the U.S. justification of self-defence at least plausible, but that it did not have sufficient information on the facts to come to a final legal assessment. Asked on 15 January 2020 whether the Federal Government shared the legal view of the Research Services of the Federal Parliament that the killing of General Soleimani could not be legitimately justified in international law the spokesperson for the Federal Foreign Ministry answered with a clear: “no”.

Germany’s reluctance to take a clear stance on the legality of the strike may also be explained by its declared policy of “de-escalation” and “utmost restraint”. Any express statement either way could have compromised its position as an intermediary between the warring parties. If anything can be deduced from the German statements for international law, then it is that the killing was considered a response to a series of past acts by Iran and not an action in anticipation of future attacks by Iran. If at all, Germany treated the U.S. action as an act of self-defence against a continuing series of attacks rather than an act of self-defence against an imminent attack.

The German view of a response to a series of military provocations by Iran closely resembled the United States’ position of defensive action against a continuing series of attacks by Iran on U.S. forces and installations in Iraq. For example, on 31 December 2019, the U.S. State Department spoke of a “campaign” of attacks directed by Iran. In a statement released on 2 January 2020 U.S. Secretary of Defense Mark T. Esper spoke of “a string of attacks against bases with U.S. forces” and “continued attacks against our personnel and forces in the region” by Iran. In its report to the UN Security Council, in accordance with Article 51 of the UN Charter, the United States also referred to a series of past attacks. It stated:

“These actions were in response to an escalating series of armed attacks in recent months by the Islamic Republic of Iran and Iran-supported militias on United States forces and interests in the Middle East region […].Over the past several months, the United States has been the target of a series of escalating threats and armed attacks by the Islamic Republic of Iran. […] The actions taken by the United States occurred in the context of continuing armed attacks by the Islamic Republic of Iran […]. Additionally, Qods Force-backed militias have engaged in a series of attacks against United States forces.”

Finally, U.S. Attorney General William Barr said at a press conference on 13 January 2020:

“This was a legitimate act of self-defense because it disrupted ongoing attacks that were being conducted, a campaign against the Americans. And it reestablished deterrence, it responded to attacks that had been already committed.”

While most commentators discussed the killing under the aspect of pre-emptive self-defence, the U.S. report to the UN Security Council in accordance with Article 51 of the UN Charter made no mention of pre-emptive self defence or an imminent armed attack. As the International Court of Justice (ICJ) pointed out in the Nicaragua case, it is not admissible “to ascribe to States legal views which they do not themselves formulate.” According to the Court, a distinction must also be made between “justifications solely advanced in a political context” and those “advanced as legal arguments.” To this it may be added that a distinction must be made between domestic (constitutional law) and international law arguments. Much of the “imminent threat” and “imminent attack” rhetoric employed by President Trump and other U.S. government officials seems to have been geared towards a domestic audience and the question of the President’s war powers under the U.S. Constitution. While the President’s power to go to war without congressional approval is limited by the Constitution and the War Powers Act of 1973, he is always permitted to defend the country and U.S. forces stationed abroad against imminent attacks. It may be for this reason that U.S. Attorney General William Barr called the concept of imminence “something of a red herring” when defending the Soleimani strike as “a legitimate act of self-defense.” It thus seems that the majority of commentators have been barking up the wrong tree when they very skillfully showed that the United States did not have a right to pre-emptive self-defence because there was no imminent armed attack. Rather than putting the killing of General Soleimani to scrutiny under the head of pre-emptive self-defence, it should be examined whether the killing was lawful as an act of self-defence against a continuing series of attacks against the United States by Iran. Three questions must be distinguished here: first, whether the use of force against Iran was lawful under the jus ad bellum; secondly, whether the killing of General Soleimani complied with international humanitarian law and international human rights law; and, thirdly, whether any breaches of international law with regard to Iraq were justified.

Justification of the killing under the jus ad bellum

Under the jus ad bellum, lawful defensive use of force would require: (1) that the attacks on U.S. forces and installations in Iraq reached the required scope and scale to amount to an armed attack on the United States in the sense of Article 51 of the UN Charter; (2) that the armed attack was attributable to Iran; (3) that at the time of the killing of General Soleimani the armed attack was ongoing, and (4) that the use of force was necessary and proportionate.

The first requirement of a lawful use of force by the United States is therefore that there existed an armed attack on the United States. Use of force falling short of an armed attack in gravity and scale must be countered through other means. The two-day siege of the U.S. embassy by KH militiamen with limited damage to property would hardly qualify as an armed attack. However, the United States does refer to “an escalating series of armed attacks in recent months” and so does Germany in its statements. The United States has long been a proponent of the so-called “accumulation of events” doctrine, according to which a series of attacks of lesser gravity and scale may collectively amount to an armed attack. The ICJ left open the possibility of an accumulation of events amounting to an armed attack. In Nicaragua, the ICJ stated that a series of forcible acts “may be treated for legal purposes as amounting […] collectively to an ‘armed attack.’” The attacks, each of which might not qualify as an armed attack in scale and effect, could reach the required threshold of gravity when taken together. This view was reiterated by the ICJ in its judgments in the Oil Platforms and Armed Activities cases. In legal proceedings before an international court or tribunal, the burden of proof that the events taken together reached the gravity threshold and constituted an armed attack under the accumulation of events theory would lie with the United States. Considering the potential of abuse, it has been rightly pointed out that the accumulation of events doctrine must be construed restrictively and should apply only where successive attacks are linked in time, cause and source. Given that the six attacks occurred within the spell of two months, were all carried out against U.S. forces and installations in Iraq, and were all perpetrated by the KH militia, the U.S. argument that the “series” or “campaign” of attacks by the KH militia amounted to an armed attack in terms of Article 51 of the UN Charter cannot be dismissed out of hand.

The attacks on U.S. troops and installations present in the territory of Iraq may be considered an armed attack on the United States. Armed attacks on a State’s outposts abroad also trigger the right to self-defence. The United States has long held the view that attacks on its military forces and installations, diplomatic and consular missions, and nationals abroad can justify action in self-defence. While there may be some argument about whether a State’s nationals and embassies qualify as “outposts” for the purposes of Article 51 of the UN Charter, it is generally accepted that an armed attack by a State on the troops of another State based by consent within the territory of a third State may be deemed an armed attack on the State whose troops have been attacked. This is also shown by Article 3(d) of the Definition of Aggression which considers attacks on the land, sea or air forces of a State abroad as an act of aggression. Such attacks may be carried out either by the armed forces of another State or by irregular forces sent by or on behalf of another State.

Secondly, the armed attack by the KH militia would have had to be attributable to Iran in order to allow for the use of force in self-defence against Iran. KH is a Shia paramilitary group in Iraq. While it is formally a part of the Iraqi armed forces, its prime loyalty lies with Iran. KH considers the Iranian Supreme Leader’s religious instructions to have primacy over Iraqi State law. It is mainly funded and trained by the Iranian Quds Forces commanded by General Soleimani. Training, equipping, funding, and providing intelligence and operational support to an armed group is not, however, sufficient for attributing KH’s acts to Iran. Under the ICJ’s “effective control” test, KH’s actions are only attributable to Iran if Tehran exercised effective control over KH’s attacks on U.S. forces in Iraq. Admittedly, the threshold is high. Considering KH’s close ties to Iran, their open pledge of loyalty to Iran and the regular meetings with General Soleimani, there may be evidence that Iran through its Quds Force planned, ordered and controlled the KH attacks on U.S. forces in Iraq. This is what the United States claimed in its official statements. Referring to KH as having a “strong linkage to the Islamic Revolutionary Guards Quds Force”, Secretary of Defence Esper stated on 2 January 2020 that the KH attacks on U.S. forces in Iraq were “directed by the Iranian regime,” “orchestrated” by Soleimani and that KH had received “direction from Iran”. In a briefing on 31 December 2019, a State Department official stated that the United States considered the KH militia “Iranian-commanded”.

Germany also considered Iran to be behind the attacks on U.S. forces in Iraq. On 3 January 2020, a spokesperson for the Federal Government referred to “a series of military provocations for which Iran bears responsibility.” While in the language of international law “bearing responsibility” is not the same as “being responsible,” the Federal Foreign Office in other statements expressly spoke of “provocations by Iran” or “Iranian provocations” and, even more to the point, “a number of attacks on US and international troop presences in Iraq by Iran and by militias supported by Iran.”

Thirdly, the legality of the use of force in self-defence requires that an armed attack “occurs.” As the United States claimed to respond to an “escalating series of armed attacks” this requires that the series of armed attacks was continuing. The question is thus whether on 3 January 2020, the United States could expect further attacks in the series of attacks of which six had already taken place since November 2019. Unlike in the case of pre-emptive self-defence, such prospective armed attacks must not be imminent. U.S. Attorney General William Barr stated on 13 January 2020: “I think when you’re dealing with a situation where you already have attacks underway, you have a campaign that involves repeated attacks on American targets, I don’t think there’s a requirement, frankly, for, you know, knowing the exact time and place of the next attack.” In case of a series of attacks, it suffices that the next expected attack forms part of the existing series of attacks. In situations where attacks do not occur on a daily basis but are more isolated, it is more difficult to assess whether a series of attacks is continuing or whether it has come to an end with the latest attack. The United States first claimed to act in self-defence on 29 December 2019 when it bombed bases of the KH militia in the Iraqi-Syrian border region. U.S. Secretary of Defence Mark Esper explained that these “attacks were aimed at reducing KH’s ability to launch additional attacks against U.S. personnel.” There is no indication that this act of self-defence ended the series of Iran-orchestrated attacks by the KH militia against U.S. targets in Iraq. On the contrary, on 31 December 2019 members of the KH militia tried to storm the U.S. embassy in Baghdad. The United States was expecting more attacks to come, as can be seen from the fact that in the wake of the siege of the U.S. embassy in Baghdad the U.S. Government deployed additional troops to the region. In his 2 January 2020 statements, Secretary of Defense Esper referred to “future Iranian attack plans” and emphasised that “General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region.” In particular, he directly warned Iran against further attacks, stating: “Let me speak directly to Iran and to our partners and allies. To Iran and its proxy militias: we will not accept continued attacks against our personnel and forces in the region.”

Finally, the use of force in self-defence must have been necessary and proportionate. In the case of self-defence against a continuing series of attacks, the necessity and proportionality of defensive action may be difficult to assess. However, it is generally agreed that even in this situation self-defence must not be retaliatory or punitive, but that its aim must be to halt the series of attacks. In his remarks on the killing of General Soleimani on 3 January 2020, U.S. President Trump made it clear that the action was intended to halt future attacks, declaring: “We took action last night to stop a war.” Other government officials also made it clear that the United States killed General Soleimani to halt and deter future Iranian attacks and to protect U.S. personnel in Iraq. Necessity requires that no alternative, less intrusive means be available to halt the series of attacks. Proportionality relates to scope, scale and target of the response. Both requirements are to be determined ex ante and the State acting in self-defence must be given a certain leeway in the assessment of the situation. In its first response to the series of Iran-backed attacks, the United States on 29 December 2019 bombed bases of the KH militia in the Iraqi-Syrian border region in order to reduce “KH’s ability to launch additional attacks against U.S. personnel.” This response, however, did not stop attacks by KH on U.S. personnel in Iraq as the attempted storming of the U.S. embassy in Baghdad by members of the KH militia a few days later showed. The United States considered Iran and, in particular, General Soleimani to be behind these attacks. U.S. President Trump stated on 3 January 2020: “The recent attacks on U.S. targets in Iraq, including rocket strikes that killed an American and injured four American servicemen very badly, as well as a violent assault on our embassy in Baghdad, were carried out at the direction of Soleimani.” The United States also argued that General Soleimani “was actively developing plans to attack American diplomats and service members in Iraq and throughout the region.” In its report to the UN Security Council the U.S. Government declared that it had killed Qasem Soleimani “in order to deter the Islamic Republic of Iran from conducting or supporting further attacks against the United States or United States interests, and to degrade the Islamic Republic of Iran and Islamic Revolutionary Guard Corps Qods Force-supported militias’ ability to conduct attacks.” If General Soleimani was indeed the “mastermind of the most recent attacks against U.S. forces in Iraq,” and if he was planning further attacks on U.S. forces and institutions in Iraq and the region, killing him in a precision strike would have been both a necessary and proportionate defensive action to halt the series of attacks by Iran and Iranian-backed militias.

Compliance with international humanitarian law and international human rights law

The armed attack by Iran and the use of force in self-defence by the United States gave rise to an international armed conflict between the two States, albeit a localised low-intensity armed conflict. Unlike non-international armed conflicts, there is no minimum threshold of intensity or duration of the hostilities. There exists an international armed conflict “whenever there is a resort to armed force between States.” This international armed conflict between Iran and the United States did not start with the killing of General Soleimani on 3 January 2020, but began much earlier with the attacks by Iran and its proxies on U.S. forces in Iraq in November and December 2019. The United States first responded to the Iranian attacks on 29 December 2019, when it bombed positions of the KH militia in the Syrian-Iraqi border region. The existence of an international armed conflict is a question of fact, irrespective of whether the parties publicly acknowledge the conflict or not.

Any defensive action taken by the United States must therefore comply with the rules of international humanitarian law regulating and limiting conduct in international armed conflicts. General Soleimani was the military commander of the Quds Force, an official branch of the regular armed forces of Iran. As a member of the Iranian armed forces he qualified as an enemy combatant. Unlike “objects”, enemy combatants may legitimately be attacked as “military objectives” irrespective of whether they make an effective contribution to military action of the enemy and whether their killing offers a definite military advantage. In any case, both requirements would have been fulfilled in the present case. According to the United States, General Soleimani had been directing the attacks against U.S. forces in Iraq. As an enemy combatant directly involved in the attacks, he was a military objective who could be lawfully targeted and attacked under international humanitarian law. U.S. Attorney General William Barr thus correctly stated the law when he said on 13 January 2020: “The general in charge of these efforts, Soleimani, was clearly a legitimate military target.” The members of the Quds Force who were killed in the drone strike also qualified as enemy combatants. Leaders of the KH militia killed in the strike could either be targeted as members of a militia forming part of the armed forces of Iran or belonging to Iran, or as civilians taking “a direct part in hostilities.” In any case, their killing may be considered proportionate collateral damage of a precision drone strike to eliminate the mastermind behind the ongoing series of attacks against the United States.

Although the United States has long considered international humanitarian law a lex specialis, which displaces the application of human rights law in international armed conflicts, the general view is that both bodies of law are, in principle, applicable side by side and are complementary. This raises the question of whether the United States was bound by its international human rights obligations when it killed General Soleimani in Iraq. The United States takes the view that, for example, the International Covenant on Civil and Political Rights (ICCPR) is not applicable extraterritorially. Again, this is largely a minority view. However, the extraterritorial application of human rights law would have required that General Soleimani was subject to the “jurisdiction” of the United States when he was killed at Baghdad International Airport. Persons outside a State’s territory are only considered to be within its jurisdiction if they are present in foreign territory under the effective control of the State or if they are subject to the physical power and control of agents of the State. General Soleimani was neither subject to the physical control of U.S. personnel nor was the Baghdad International Airport area under the effective control of the United States. Control of the airspace above a foreign territory is not considered sufficient. Similarly, a “cause-and-effect” notion of jurisdiction has been dismissed. The violation of a right does not automatically establish jurisdiction over the person affected. Thus, in the Banković case, the European Court of Human Rights found that the killing by a State of a person in an airstrike in a foreign country did not establish jurisdiction over that person and that, consequently, the case was not admissible. The finding of a violation of General Soleimani’s rights under the ICCPR is thus excluded due to the lack of a jurisdictional link between him and the United States. However, even if the ICCPR had been applicable in the present case, the killing of General Soleimani would not have violated his right to life under the Convention. Article 6(1) of the ICCPR prohibits only the arbitrary deprivation of life. The killing of a combatant during an international armed conflict in accordance with international humanitarian law cannot be considered arbitrary.

Justification of any breaches of international law with regard to Iraq

General Soleimani and members of his entourage were killed together with a high-ranking Iraqi military leader and several Iraqi citizens at Baghdad International Airport without the approval of the Government of Iraq. The Iraqi Government subsequently condemned the killing “in the strongest possible terms” as an act of “aggression”, a “flagrant violation of the terms under which U.S. forces are present in the country,” and a violation of “the sovereignty of Iraq and the principles of international law.” This raises the question of whether possible breaches of international law with regard to Iraq could be justified on the basis that the United States acted lawfully in self-defence under the jus ad bellum.

Self-defence is accepted in customary international law as one of the circumstances precluding the wrongfulness of the use of force. For example, Article 21 of the Articles on State Responsibility, adopted by the International Law Commission (ILC) in 2001, provides:

“The wrongfulness of an act of State is precluded if the act constitutes a lawful measure of self-defence taken in conformity with the Charter of the United Nations.”

While the United States used force in self-defence in Iraq, it did not use defensive force against Iraq. Although the attacks on U.S. forces in Iraq were carried out by the KH militia, which formally forms part of the Iraqi armed forces, the United States was not attacked by Iraq but by Iran. When carrying out the attacks KH did not act as an organ of the State of Iraq. KH had been trained, equipped, and funded by the Iranian Quds Forces and its prime loyalty lay with Iran. It is apparent that KH did not attack U.S. and coalition forces on the orders of the Iraqi Government, especially as several Iraqi policemen and soldiers were also killed and wounded in the attacks. When KH militia members carried out the attacks against allies of the Iraqi Government who were present in the country with the consent of that Government and entitled to its protection under international law, they deliberately put themselves outside the command and control structures of the Iraqi Government; that is, they did not act in their capacity as members of the Iraqi army. Article 7 of the ILC Articles on State Responsibility attributes to the State unauthorised or ultra vires acts of an organ of the State only if the State organ “acts in that capacity.” The situation here is not one of excess of authority by a State organ, but one of a State organ being placed at the disposal of another State. Rather than being so placed by the Iraqi Government, though, KH placed itself at the disposal of Iran. In this case, the conduct of KH can be considered only an act of Iran.

While the essential effect of Article 21 of the ILC Articles on State Responsibility is to preclude the wrongfulness of conduct of a State acting in self-defence vis-à-vis the attacking State, the ILC pointed out that “there may also be effects vis-à-vis third States.” In particular, Article 21 “leaves open all issues of the effect of action in self-defence vis-à-vis third States.” It has long been accepted that acts of self-defence by a belligerent on the territory of a neutral or non-belligerent State may be considered lawful if the territory is used by the enemy as a base for military operations against the belligerent, or if the troops of a belligerent, which are lawfully present in the territory of a neutral or non-belligerent State, are attacked there by the enemy. Under the principles contained in the Charter of the United Nations, the use of force in self-defence in such a situation, however, can only be lawful if the measures taken are necessary and proportionate to put an end to the armed attack.

The measures taken by the United States in the territory of Iraq must be considered necessary if there was no alternative means available to halt the series of attacks against U.S. personnel in that country. The standard applied here is that of “unable or unwilling” – defensive force may be used if the neutral or non-belligerent State is unable or unwilling to prevent the use of its territory for purposes of hostile military operations against the belligerent. It was this standard U.S. State Department officials were referring to when they said in a special briefing on the bombing of KH positions in the Iraqi-Syrian border region on 29 December 2019:

“[W]e have warned the Iraqi Government many times, and we’ve shared information with them, to try to work with them to carry out their responsibility to protect us as their invited guests. […] So it’s their responsibility and duty to protect us, and they have not taken the appropriate steps to do so.
[W]e’ve been voicing our concerns over these kinds of attacks against bases that are hosting coalition forces. We’ve voiced our concerns with senior Iraqi Government officials repeatedly. We have asked them to arrest and bring to justice the perpetrators. […] the Iraqi Government needs to ensure the safety of American forces, and there’s just been too many attacks, attempted attacks against American and Iraqi forces.”

Only hours before the Soleimani strike, U.S. Secretary of Defence Esper again drew attention to the unmet request for protection stating:

“In response [to the attacks on U.S. troops by KH militias in November and December 2019], […] we have urged the Iraqi government to take all necessary steps to protect American forces in their country. I personally have spoken to Iraqi leadership multiple times over recent months, urging them to do more.”

This “unable or unwilling” doctrine in the context of trilateral inter-State relations must not be confused with the more recent doctrine of the same name which was used by the United States and other States in the context of the so-called “war on terror”. The second doctrine was intended to justify measures of armed self-defence against non-State actors on the territory of another State which refuses or does not have the military or law enforcement capabilities to eliminate a terrorist threat emanating from its territory. While the latter is highly controversial and prone to abuse, the former – the original, so-to-speak – has long been recognised in international law. Where a neutral or non-belligerent State (Iraq) does not fulfil its duties – is unable or unwilling – a belligerent (the United States) is permitted to use force in self defence on the territory of that State against the enemy (Iran).

A precision drone strike killing the military leader who was considered the mastermind behind the Iranian attacks on U.S. forces in Iraq while that leader was present in Iraq must also be considered a proportionate response to the series of attacks; especially as the nine members of his entourage also killed in the strike were either enemy combatants or KH militia members involved in the attacks against the U.S. forces in Iraq.


The argument of self-defence against an armed attack by Iran on U.S. personnel in Iraq constitutes a credible and convincing justification of the killing of General Soleimani under international law. The argument, however, hinges on the facts: namely, (1) whether the attacks by the KH militia on U.S. personnel formed part of a series of attacks that, at the time of the killing, could be considered as continuing, and (2) whether Iran exercised effective control over KH’s attacks on U.S. forces in Iraq. Without detailed knowledge of these facts no legal assessment of the killing can be made. The German reaction to questions on the legality of the killing indicates that the United States did not share the relevant intelligence with the Federal Government – in that case, Germany was genuinely unable to assess the killing in terms of international law. Alternatively, it may have been unwilling to do so for political reasons.

Category: Use of force


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  • Stefan Talmon

    Stefan Talmon is Professor of Public Law, Public International Law and European Union Law, and Director at the Institute of Public International Law at the University of Bonn. He is also a Supernumerary Fellow of St. Anne’s College, Oxford, and practices as a Barrister from Twenty Essex, London. He is the editor of GPIL.

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  • Miriam Heipertz

    Miriam Heipertz is a law student at the University of Bonn, where she is also student research assistant at the Chair for German, Comparative and International Criminal Law.

    View all posts

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