Home EJIL Analysis The Legality of Turkey’s Possible Self-Defence Action against ISIS: A Response to Ashley Deeks

The Legality of Turkey’s Possible Self-Defence Action against ISIS: A Response to Ashley Deeks

Published on June 25, 2014        Author: 

SinaSina Etezazian is a PhD Candidate at Monash Law School.

In a recent blog post at Lawfare, Professor Ashley Deeks analyses the manner in which Turkey may lawfully protect the Turks taken hostage by the jihadist group ISIS (the Islamic State in Iraq and Syria).  She contends that ‘if the Maliki government loses total control of the country, Turkey almost certainly would be legally justified in using force in Iraq to rescue its nationals’ in accordance with Article 51 of the UN Charter.  She also takes the view that the forcible protection of citizens abroad may be equated with permissible self-defence when:

(1) the nationals in question face imminent threat of (or have suffered actual) injury;

(2) the host state is unwilling or unable to protect or rescue them; and

(3) the action of the intervening state clearly is limited to the goal of rescuing its nationals – that is, it is not engaging in pretextual intervention.

However, Deeks is on shaky legal ground concerning the ‘unwilling or unable’ and ‘last resort’ requirements. I do not aim here to consider the legal status of the protection of nationals abroad; I have discussed it elsewhere  (and it has also been addressed in length on this and other blogs and forums since the Russian intervention in Crimea). Instead, I want to explore a distinction that can be drawn between forcible responses to territorial and non-territorial attacks with respect to the ‘unwilling or unable’ and ‘last resort’ tests, clarifying why – contrary to what Deeks asserts – Turkey might not be allowed to undertake unilateral forcible measures to protect its nationals in Iraq on the basis of the right of self-defence.

The ‘Unwilling or Unable’ Test and a Distinction between Responses to Territorial and Extraterritorial Attacks

The point that Deeks makes regarding the ‘unwilling or unable’ test can hardly be said to reflect existing law, as it is founded on the claim that ‘unwilling or unable’ extends to the protection of nationals abroad, which is itself a very controversial issue in modern jus ad bellum. Let us suppose for the sake of argument that ‘unwilling or unable’ qualifies as a new norm of customary international law that allows for the exercise of the right of self-defence against non-state actors when the host state is unwilling or unable to prevent its territory being used as a base for launching attacks against the victim state’s soil. Even allowing that position, it is extremely unlikely that its scope has been so widened as to include the military rescue of nationals threatened extraterritorially.

It is true that the ‘unwilling or unable’ test has attracted some level of support from the international community since 9/11, especially when the attack has been directed against the territory of the victim state (as was apparent from states’ reaction to the September 11 attacks). Nonetheless, the most recent trend in state practice clearly demonstrates that the argument for ‘unwilling or unable’ would be uncertain at best in scenarios where Article 51 has been invoked to rescue nationals allegedly at risk outside their territory. Russia, for example, soon after it intervened militarily in Ukraine, chose to shift away from the forcible protection of nationals abroad towards ‘intervention by invitation’ as the main legal justification for its action. Similarly, in February when five Iranian soldiers were abducted by the militant organisation Jaish-ul Adl and taken across the border to Pakistan, Iran sought to rely on peaceful measures, not self-defence action, to secure their freedom. This was despite the fact that one of the Iranian officials had been quoted as warning that ‘if Pakistan doesn’t take the needed steps to fight against the terrorist groups we will send our forces into Pakistani soil.’ Importantly, even when Jaish-ul Adl announced that it had executed one of the soldiers, rather than respond with force in self-defence, Iran wrote a letter to the UN Secretary General, urging ‘the global community’ to cooperate with the Iranian government on the release of its nationals and to tackle the threat posed by extremists in the Middle East.

Returning to the current crisis, Turkey has ‘agreed to try diplomatic methods to bring about the hostages’ release.’ Thus, in spite of the fact that Turkish ministers ‘are said to be assessing military options too’, Turkey has not claimed defensive force to regain custody of its citizens. It is therefore beyond doubt that the ‘unwilling or unable’ test has weak legal standing in cases where the attack has been extra-territorial, including where it has been directed against citizens overseas (assuming that the attack or its imminent threat against nationals abroad meets the definition of armed attack for the purpose of lawful self-defence).

The Last Resort’ Requirement and a Distinction between Responses to Territorial and Extraterritorial Attacks

Moreover, by suggesting that, should the Iraqi government lose ‘total control of the country’, force can be used in self-defence against ISIS to protect the kidnapped Turks there, Deeks would seem to adopt a very broad approach to ‘last resort’ as a requirement inherent in the necessity of defence. The ‘last resort’ requirement means that the claimant state may use force within the meaning of Article 51 only if non-forcible measures are unlikely to be practicable to bring the conflict to the end. This view can be inferred from customary international law governing self-defence and the view of a number of highly respected commentators published by The Chatham House Principles of International Law on the Use of Force in Self-Defence (page7), along with the jurisprudence of the International Court of Justice (ICJ) and the relevant contribution (paragraph 120) made by the International Law Commission (ILC).

In fact, the total loss of control may not be taken as evidence that options other than force have become impracticable to resolve the tension in question. Going back to the Iranian border guards taken hostage in Pakistan, for example, it was some Sunni clerics inside Iran, not the Pakistani government, who played a major role in convincing Jaish-ul Adl to release the soldiers. In other words, mediation as a non-coercive means of dispute resolution could practicably settle the given situation, no matter how effective the Pakistani government had been in terms of control of its country during the crisis. Likewise, the extent of control the Maliki government exerts over Iraq appears unlikely to be a particularly relevant factor in determining whether the ‘last resort’ criterion of necessity has been met.

Another important issue to take into account with regard to ‘last resort’ is a distinction that can be drawn between responses to territorial and non-territorial attacks – although such a distinction has yet to acquire the status of customary international law (James A Green, The International Court of Justice and Self-Defence in International Law, pages 76-86). Since the establishment of the UN, when faced with extra-territorial attacks, states have been more willing to pursue options entailing negotiations prior to the use of force. Examples include the measures taken by the United States before acting forcibly against Cambodia in 1975 (the Mayaguez crisis) and the perceived terrorists targets in Afghanistan and Sudan in 1998. On the contrary, when the attack to which the victim state is responding has occurred against its territory, the victim state is much more inclined to resort to self-defence immediately, as demonstrated by the Seychelles’ prompt self-defence action in response to the terrorist attack that was undertaken against its territory in 1981.

The position that one can take concerning the distinction between territorial and extraterritorial attacks was somewhat reinforced in April 2010 when Leiden Policy Recommendations on Counter-Terrorism and International Law (paragraph 39) concluded that ‘[I]n the case of an attack by terrorists that is not attributable to a state, Article 51 should be read to require that the attack be large-scale in order to trigger the right of self defence’. The Leiden Recommendations reflect the work of government legal advisers as well as international law scholars and legal practitioners from a number of states. As the Recommendations made clear, ‘in assessing the scale (of such attack), account may be taken of a series of attacks emanating from the same territory and the same terrorist group’. No doubt an attack on the nationals abroad (or its imminent threat), as might occur to the kidnapped Turks in Iraq, does not meet the criteria set out by Leiden Recommendations, and therefore may not constitute the threshold of an armed attack that would give rise to the right of self-defence.


The question of whether the ‘unwilling or unable’ test has crystallised as a rule of custom is one thing. The controversy as to whether the test in question has anything to do with the use of force against non-state actors to defend citizens threatened overseas is quite another. Certainly, in the wake of 9/11, the international community has increasingly accepted the idea of a victim state engaging in self-defensive measures against non-state actors in another state’s territory when that state has proved unable or unwilling to prevent the non-state actors from attacking the victim state’s territory. However, the radical expansion of the ‘unwilling or unable’ test, as proposed by Deeks with regard to the protection of nationals abroad, appears to have no foundation in state practice and opinio juris relating to defensive action. The same can be said of Deeks’ conception of the ‘last resort’ requirement. Even if Maliki’s administration at some point becomes totally unable to assume control of Iraq, Turkey would not be entitled under current international law to resort to self-defence with the aim of protecting its nationals taken into custody there. Leaving aside the matter of legality, furthermore, in cases of citizens under threat outside their territory, diplomacy seems to have been a more effective and reliable path than the resort to force.

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12 Responses

  1. […] On EJILTalk: The Legality of Turkey’s Possible Self-Defence Action against ISIS […]

  2. Jordan

    Thanks for the interesting viewpoints. I would state that there is no “unwilling or unable” limitation of the inherent right of self-defense under CIL or Article 51 of the U.N. Charter and there is no requirement that lawful measures of self-defense be a “last resort” — assuming, according to the majority view, that an armed attack has begun or is underway or that a process of armed attacks is ongoing. Also, the vast majority of writers agree that non-state armed attacks can trigger the right if self-defense, e.g., Chatham House group and see
    see also the new draft article at

  3. Jordan

    p.s. one is reminded of the Israeli use of force in a surgical fashion to save Israeli nationals from execution in Uganda when they had been under armed “attack” by non-state actors that were holding them as hostages.

  4. Ian Henderson


    Noting your Iran and Turkey examples, could both of these examples also be interpreted as each State claiming the legal right to use force but choosing not to for non-legal reasons?

  5. Sina Etezazian


    Thanks for the comments.

  6. Sina Etezazian


    Thanks for the question. In my view, it would be difficult to draw such a conclusion. Rather, given the fact that both Iran and Turkey had/have not invoked the right of self-defence to protect their citizens in danger extra-territorially (in these cases) but instead had/have relied primarily on options not involving force may be seen as an indication that these states have willingly adopted a legal obligation to refrain from taking unilateral coercive measures under such circumstances – even where the host state is unwilling or unable to protect their nationals.

  7. Jordan

    From: Carmi Lecker [mailto:%63%61%72%6D%69%2E%6C%65%63%6B%65%72%40%67%6D%61%69%6C%2E%63%6F%6D]
    Sent: Thursday, July 03, 2014 10:24 AM
    Subject: New York City Bar Association Releases Report on Legality of Targeted Killings by U.S. Drones Under International Law/19.6.14

    City Bar Releases Report on Legality of Targeted Killings by U.S. Drones Under International Law
    Thursday, Jun 19, 2014 – 3:28pm
    Anticipating that targeted killings by drones may increase in the future, both by the United States and by other countries, the New York City Bar Association today released a report analyzing the legality of targeted killings by drones launched by the United States in the context of international law.
    While noting that there are serious constitutional, moral and policy issues associated with targeted killings using drones, some of which the City Bar has addressed elsewhere, today’s report—titled “The Legality Under International Law of Targeted Killings by Drones Launched by the United States”—deals strictly with the legality of drone strikes under current international law. The 181-page report characterizes the international legal issues as “complex,” and the analysis “complicated” because, among other reasons, “although the analysis of the legality of a drone strike is highly fact-specific, the facts surrounding the strikes are unclear.”
    Based on the facts in the public record, the report concludes that while the U.S. invasion of Afghanistan was a legitimate act of self-defense in response to the 9/11 attacks by al-Qaeda, those attacks no longer supply a legal basis for additional measures, such as drone strikes, against al-Qaeda or its alleged affiliates. Rather, under international law, “If the continued use of force is to be justified on the basis of self-defense, it must be justified by current armed attacks,” the report states.
    Under international law, the Report concludes, “the inherent right to self-defense is available against non-State actors, such as terrorist groups…if there is an actual or threatened ‘armed attack’ by the non-State actor.” In exercising the right of self-defense, the State may use force against a non-State actor, constrained by the principles of necessity and proportionality, within the territory of another State so long as force is directed against that actor and not another State, even in certain circumstances before an armed attack has occurred if the State has “no choice of means” to protect itself short of the use of force. The report observes, based on publicly-available information, that many States appear to have consented to U.S. drone strikes, making unnecessary any self-defense analysis.
    The use of force in another State’s territory without its consent, based on a claim of “self-defense,” triggers a duty to make disclosures to the United Nations Security Council under Article 51 of the UN Charter, the report explains. “[I]f Pakistan currently denies consent to U.S. drone strikes, as it has stated publicly, the U.S. has a duty to report to the Security Council on its invocation of Article 51 with respect to those strikes,” the report states. “Consistent with its prior practice, the U.S. should disclose the armed attack(s) giving rise to the right to act in self-defense and the measures that the U.S. is taking in the exercise of that right. It does not appear that the U.S. has met its disclosure obligations under Article 51 with respect to Pakistan.”
    Even if the use of force on another State’s territory is lawful, the report explains, the legality of killing a particular individual depends upon the existence of an armed conflict. According to the Report, “Except in extreme circumstances, a targeted killing outside of an armed conflict is almost certain to be contrary to [International Human Rights Law], which guarantees to each individual the right to life.” Whether an “armed conflict” exists is a determination that must be made on a State-by-State basis by considering the “intensity of the conflict” and “whether the individual non-State organizations in those countries have the structure required to qualify as ‘parties’ to an armed conflict.” The report explains that the issue of an alleged “global war” is irrelevant under international law if the United States is involved in domestic armed conflicts within individual States, even against different parties.
    The Report states that where it is determined that the United States is involved in an armed conflict with a non-State actor, “we follow the [International Committee of the Red Cross] Guidance that the principle of distinction permits the United States to target and kill a member of the non-State actor’s ‘armed forces,’ i.e., a member of the armed group who performs a ‘continuous combat function,’” the report states.
    Beyond the Article 51 requirements concerning the use of force on another State’s territory, the report concludes that “the United States is not required to make further disclosures on targeted killings under international law, no matter how desirable such disclosures might be as a matter of policy or ethics.”
    The Report makes clear that it “does not address the legality of the targeted killings under domestic U.S. law. Nor does it discuss the appropriate policy that should be followed even if that policy is not prohibited by law. However, we recognize that decisions regarding the U.S. targeted killings policy must be considered in the context of this nation’s democratic process. There are serious constitutional and other implications of conducting a largely secret war, and policy issues on its wisdom and morality. Thus, this Bar Association has urged that the U.S. Government make public the legal justification of its targeted killings policy. In a 2012 letter to President Obama, Association President Carey R. Dunne said, ‘Given the importance and relative novelty of the drone strategy, we believe this program should be the subject of informed public discussion and that, so long as the program is in use, decisions to use drone strikes should be made with the strictest of scrutiny and in a manner best calculated to avoid collateral damage.’”
    For the full report, click here:
    For the introduction and executive summary only, click here:
    This entry was posted in New York City Bar Association and tagged Article 51,drones, International Committee of the Red Cross, International Human Rights Law,International Law, New York City Bar Association, targeted killings, United Nations Charter. Bookmark the permalink

  8. Ian Henderson


    I am afraid I do not follow. Looking at what you originally wrote (“…one of the Iranian officials had been quoted as warning that ‘if Pakistan doesn’t take the needed steps to fight against the terrorist groups we will send our forces into Pakistani soil.’ … Turkish ministers ‘are said to be assessing military options too’”), I inferred that both governments had asserted (or at least implied) a right to use force but had chosen to pursue other means. Just because a State opts to see if one course of action works, that is not the same as foregoing the legal right to pursue other courses.

  9. Sina Etezazian

    Many thanks, Jordan. That was helpful.

  10. Sina Etezazian


    Of course, Iran had initially threatened to use force to rescue the Iranian border guards taken hostage in Pakistan. What matters most, however, is that Iran had not threatened to use force (against the kidnappers) on the basis of Article 51; it had not invoked the right of self-defence.

    Besides, Iran immediately chose to distance itself from the language of force and instead opted to rely on non-forcible measures to settle the problem. That is, the Iranian government had clearly modified its initial position, no longer maintaining that it would act forcibly if the Pakistani government fails to take action to protect the Iranian soldiers threatened there. The conclusion that Iran had no longer believed that it would be entitled to use force in such a case may be seen from the fact that, even after Jaish-ul Adl stated that it had killed one of the Iranian soldiers, Iran sought to insist on pursuing non-coercive options. That is, Iran wrote a letter to the UN Secretary General, calling for the international community to cooperate with Iran on the release of its citizens. And, importantly, in the letter submitted to the UN Secretary General, Iran did not assert a legal right to engage in forcible measures against the Kidnappers.
    Similarly, in the case of the kidnapped Turks, ‘the Turkish ministers are said to be assessing military options too’. Even, Turkey had ‘threatened to retaliate if any of its citizens are harmed. These statements, however, may not amount to an assertion of the right of self-defence (or a legal right to resort to military action).

  11. Jordan

    It seems that “unwilling or unable” and “last resoprt” are only relevant if one accepts a minority view that self-defense can be permissible before an armed attack has begun or is underway. Also, “imminent threat” is not even a present threat — much different than a claim regarding a threat of an imminent armed attack.

  12. Hanalp

    Thanks for this post and discussion. Despite I do fully agree with the point you raised about “protecting the nationals abroad” in general, I do have some concerns about the application of this discussion to the case you have given. My first query is that … isn’t these ISIS attacks are related more with an assault on a diplomatic mission and consulate (which – although not explicitly responded in the ICJ’s Iranian Hostage Case, etc – is widely regarded as a right of self-defence by judicial and state practices, such as the US embassies in Nairobi etc) rather than a protection of nationals abroad? My second concern is on the unwillingness and inability of Maliki government to step in. I do not really think that these aspects are politically and legally viable thresholds anymore, 1) as this territory is already a grey zone between the central government and the local Kurdistan who is practically fighting against ISIS and 2) as Maliki government has already lost effective control in this region to the ISIS, who declared its own state there. So, if Turkey has a right of self-defence, visa versa, Maliki’s potential future declarations/statements demonstrating his willingness or ability to step in will have a very contested legal and political value (even with implied consent). And lastly, the point you have raised about the distinction between territorial and extraterritorial attacks by quoting from the Leiden Recommendations, where is says that ‘in assessing the scale (of such attack), account may be taken of a series of attacks emanating from the same territory and the same terrorist group” and your conclusion on peaceful resolution also looked a bit contested for me. Simply because, for decades, this exact same geography has witnessed continuous PKK strikes to the Turkish territories from the Kurdistan, and neither these facts nor Iraqi unwillingness and inability to prevent them nor Turkeys will for peaceful solutions were the prime causes of Turkey’s hesitation to wage full fledged self-defence attack to Iraq. It was basically the same reason put forth by the ICJ in Uganda v DRC case. So, applying the Leiden threshold you put forth to this case is rather questionable in my opinion. In a nutshell, I think the case of ISIS and capturing of Turkish nationals in Iraq are more multi-dimensional legally and politically speaking than merely considering it as a case of “protecting the nationals abroad” …. Thanks …