Turkish Military Intervention in Mosul: A Legal and Political Perspective

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In October 2016, Turkey deployed hundreds of its armed troops to the Iraqi town of Bashiqa, 12 kilometers northeast of Mosul held by Islamic State. Meanwhile, Iraqi officials have called for Turkey to withdraw its forces from Iraq’s territory. Relevantly, one of the most important questions is whether Turkish military intervention in Northern Iraq has a legal basis.

First of all, it should be noted that, although there have been serious violations of human rights (mainly sectarian and ethnic divisions within the area) during the internal armed conflicts in Iraq, legally any reason cannot be accepted as a justification for military interventions and violations of the sovereignty and territorial integrity of a State. From this point of view, Turkish intervention in Iraq is a violation of the principle of respect for territorial integrity and political independence of the States which includes the inviolability of the territory of the State. As stated by the International Court of Justice (ICJ) (for example in Accordance with International Law of the Unilateral Declaration of Independence of Kosovo, Advisory Opinion, 2010, para. 80), the principle of territorial integrity, which is underpinned by the prohibition of the use of force in customary international law  and Art. 2(4) of the United Nations Charter is an important part of the international legal order and its scope is confined to the sphere of relations between States. By the way, although the recent Turkish military intervention in Mosul is not its first-time violation in Iraq –it has consistently attacked PKK (Partiya Karkerên Kurdistanê) militants in Iraq since 2003– it should be noted that the justification given by Turkey for the violation of the principle of territorial integrity that it has just conducted in Northern Iraq, is self-defense against Islamic State and the PKK.

Claims Based on the Frontier Treaty 1926 Between Turkey and Iraq

Historically, Mosul was part of the Ottoman Empire until the end of World War I, but as a result of the occupation of Mosul by Britain in 1918 after oil was found in the region, the issue- settlement of the Frontier between Turkey and Iraq- was redirected to The League of Nations Council. The League found that Iraq should retain Mosul, and as a result the new Republic of Turkey reluctantly assented to the decision by signing the “Frontier Treaty” with Iraq in 1926. Finally, Turkey was convinced to peace by supporting the independence of Iraq. Moreover, Turkey agreed to act according to the Treaty mainly because Iraq agreed to give a 10% royalty on Mosul’s oil deposits to Turkey for 25 years (art. 14). The 1926 Frontier Treaty which is known also as the Ankara Treaty was signed in Ankara on June 5, 1926 by the United Kingdom and Turkey to determine political borders between Turkey and Iraq and to regulate neighborhood relations. The Treaty contains a preamble and 18 articles and entered into force on February 20, 1926.

According to the common view among the majority of Turkish scholars and as stated by former Turkish President Abdullah Gul, by signing the 1926 Treaty Turkey left Mosul to Iraq only on the condition of “non-disruption of the national unity and the territorial integrity of Iraq in any case” (see “Abdullah Gül: Irak Bölünürse, Hakkımız Doğar”). In this regard, they claim that since currently the national unity and the territorial integrity of Iraq has been disrupted as a result of Islamic State’s terrorist actions and occupation of a main part of Iraq’s Northern territory, Mosul by this armed group, Turkey has intervened in Mosul to fight against Islamic State because Islamic State’s terrorist acts in the frontier zone also threaten Turkish national security and its sovereignty. Furthermore, they believe that the Turkish attitude is grounded in the statement, “by all means in their power”, of Article 6 of the 1926 Treaty which reads: “The High Contracting Parties undertake reciprocally to oppose by all means in their power any preparations made by one or more armed individuals with the object of committing acts of pillage or brigandage in the neighbouring frontier zone and to prevent them from crossing the frontier”. In other words, by a broad interpretation of this provision they argue that the provision of Article 6 allows Turkish military to intervene in Iraq in order to ensure the sovereignty and territorial integrity of Iraq in Mosul which is majorly inhabited by ethnic Turkmens who associate themselves with Turkic ethnic origins and mostly adhere to a Turkish heritage and identity. Turkey also relates its intervention to the protection of its kinsmen in the region.  From this point of view, occupation of, and committing terrorist attacks in, the frontier zone of Turkey-Iraq could be interpreted as acts of “pillage or brigandage in the neighboring frontier zone of Turkey-Iraq” as stated in Article 6 of the 1926 Treaty.

However, it should be noted that these justifications do not have a legal basis. First, application of the 1926 Treaty on the condition of non-disruption of the national unity and the territorial integrity of Iraq is not a part of the 1926 Treaty as an international frontier treaty. Secondly, a broad interpretation of Article 6 in order to confer the right to military intervention in Iraq’s territory is inconsistent with the Treaty’s objects and purpose. Actually, such interpretation is not in compliance with the ordinary meaning to be given to the terms used in Article 6 of the Treaty. According to the 1969 Vienna Convention on the Law of Treaties, “A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose” (art. 31(1)). As Shaw argues, “…any true interpretation of a treaty in international law will have to take into account all aspects of the agreement, from the words employed to the intention of the parties and the aims of the particular document. It is not possible to exclude completely any one of these components” (International Law, 7th Edition, 2014, p. 676). From this point of view, it would not be accurate to state that the provision of Article 6 of the 1926 Treaty allows military intervention of States parties in each other’s internal affairs, because the boundary treaties between States are signed based on mutual respect for the sovereignty and respective rights and interests of the parties. It means that the boundary treaties cannot be interpreted broadly in favor of one side of the Treaty. In simple terms, a broad interpretation of the provisions foreseen in the boundary treaties between two or more States could cause them to go beyond the international norms.

Nevertheless, Turkish violations of Iraqi sovereignty and its territorial integrity by military intervention in Mosul could be discussed in the context of some of the political justifications. As argued by Turkish officials, Turkey is seeking to protect its economic and political interests in Mosul (Northern Iraq) while fighting against PKK and the Islamic State. Politically, Mosul is very significant for Turkey, not only for Islamic State being in the Iraqi territories but also for the presence of the PKK in this region that genuinely threatens Turkish national security in the Turkey-Iraqi border region. It has been evidenced that the PKK has established a de facto and military administration in Sinjar, west of Mosul after entering to Sinjar to fight against Islamic State as the Sinjar resistance (see Chulov/Hawramy, “Peshmerga Forces Enter Sinjar in Fight Against ISIS”). Practically, Turkey’s main concern is the filling of any possible power gap emerging in Northern Iraq by the PKK. In other words, although Sinjar is rescued from the Islamic State occupation, the Iraqi central government still has no power to manage this region.

From a legal point of view, as the ICJ pointed out in the Corfu Channel Case, “the alleged right of intervention [is] the manifestation of a policy of force, such as has, in the past, given rise to most serious abuses and such as cannot find a place in international law”(Corfu Channel Case, Judgment of April 9th, 1949: ICJ Reports (1949), p. 35). Accordingly, respect by independent States for each other’s territorial integrity and sovereignty forms the basis of international relations. However, it could be said that from a political point of view, military intervention in Mosul by Turkey as a country that has been confronted with terrorist actions of separatist militants of the PKK for more than 40 years, is justifiable. Quite differently, in this case, international law prohibits such an intervention under any circumstances. What is more, the Iraqi government is not able to take any action towards the PKK which has occupied Iraqi territory in Sinjar in violation of Iraq’s sovereignty. In a short sense, strengthening of the PKK in Iraq means that Turkish national security will inevitably be even more threatened. From this perspective, it may be said at first sight that Turkish military intervention in Iraq based on the right of self-defense is justifiable by the inability and unwillingness of the host State, Iraq, to suppress the threats of non-state armed groups. However, as the ICJ stated, “There is no rule in the customary international law permitting another State to exercise the right of self-defense on the basis of its own assessment of the situation”(see Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America). Merits, Judgment I.C.J. Reports 1986, para. 195, p. 104).  This means that the ICJ also has not accepted the theory of unwilling or unable. In other terms, it is only a theory that has no basis in customary international law.

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Taciano S. Zimmermann says

January 27, 2017

Dr. Bagheri,

Congratulations for your analysis.

With regard to the last paragraph, however, it seems to me that the excerpt of the Nicaragua case that you mentioned cannot be a valid basis to affirm that the ICJ has not accepted the "unwilling or unable" theory. Put within its context, the passage refers specifically to the right of 'collective' self-defense, meaning that a third State cannot respond to an armed attack carried out against another State unless this State -- i.e., "the State for whose benefit this right [of collective self defense] is used" -- declares "itself to be the victim of an armed attack" (ICJ, Nicaragua case, para. 195). Nonetheless, based on other cases (DRC vs. Uganda, Wall, and other parts of Nicaragua), your conclusion remains accurate, as the Court has developed a quite restrictive jurisprudence on the law of self defence.

Best regards,

Saeed Bagheri says

January 28, 2017

Dear professor Zimmermann,
Many thanks for your attention. Definitely, I agree with you, but here I tried to read the ICJ's decision (para. 195) broadly. So, I believe that the prohibition of exercising the right of collective self-defense on the basis of State' own assessment could be interpreted as unacceptability of intervention in a country, combined or individually, on the basis of the right of self-defense. the same way! However, I agree with you that the ICJ's "Wall" and "DRC vs. Uganda" () cases are rather relevant.

Warm regards,

Ender Özeke says

January 28, 2017

Dr. Bagheri,

With all due respect, I believe the article does somewhat injustice to Turkey's position in that there is a lot of debate around self-defence under international law and for the sake of completeness, mention should have been made, at least in passing, of the evolving principles of international law that could support Turkey's position re self-defence, even if these are not sufficiently made by Turkey herself.

I will just quote the two sentences from para. 147 of the DRC v. Uganda case:

"For all these reasons, the Court finds that the legal and factual
circumstances for the exercise of a right of self-defence by Uganda against the DRC were not present. Accordingly, the Court has no need to respond to the contentions of the Parties as to whether and under what conditions CONTEMPORARY international law provides for a right of self-defence against large-scale attacks by IRREGULAR FORCES." (capitalized emphasis are mine and I should also concede that the preceding paragraph refers to DRC's (lack of) involvement in the ADF attacks on Uganda)

I should mention that I am not an expert in international law and not necessarily a fan of "pre-emptive self-defence", particularly its post 9/11 version.

Kind regards

Saeed Bagheri says

January 29, 2017

Dear Mr. Özeke,

Thank you for your comment.

Undoubtedly, Turkey as the border State has right to protect its national security against any terrorist attacks. However, it cannot really justify the interpretation of frontier treaties on the basis of Turkey’s interests. In a sense, international law consisted of principles that restrict all “States’ freedom of action on the basis of their own assessments”. Therefore, it cannot be accepted that States legally have right to intervene in other’s national affairs contrary to the general principles of international law including the obligation to respect the sovereignty and territorial integrity and non-intervention in the internal affairs of States. With regard to the right of self-defense, it is clear that the ICJ's position in this case (para. 147) is obscure and in dispute. Actually, self-defense against non-state actors is undoubtedly one of the controversial issues in international law. However, it seems likely that Ithe ICJ's jurisprudence is based on the restriction of self-defense against non-state armed groups, where para. 139 of the ICJ in the Wall Case reads: “Article 51 of the Charter thus recognizes the existence of an inherent right of self-defense in the case of armed attack by one State against another State”.

All the best,


John Wick says

January 30, 2017

This line in the last paragraph of your article is clearly taken out of context: “There is no rule in the customary international law permitting another State to exercise the right of self-defense on the basis of its own assessment of the situation”. To then claim that the ICJ rejects the unwilling/unable doctrine on this basis is an ipse dixit.

Saeed Bagheri says

January 31, 2017

Dearest John,

In summary, I simply mean in the last line of the analysis that the ICJ has not accepted generally the unwilling/unable doctrine, where the Court has consistently emphasized that Article 51 of the UN Charter limits self-defense against non-state actors to situations in which the non-state actor’s armed attacks are in some way imputable to the State whose territorial sovereignty is being violated. Nevertheless, this does not mean that the “unwilling or unable” standard has been entirely rejected by the Court. Once more, I would like to remind that the “unwilling or unable” doctrine is one of the controversial issues in international law and therefore, the existence of the different opinions or perspectives on it is inevitable!