Discussions questioning the general legal framework concerning the use of military force against the non-state actors (NSAs) in the Middle East and North Africa (MENA) region have been ongoing for a considerable amount of time. The main reason for such discussions has been the acute problem of the rapid proliferation of armed NSAs across the region in the last few decades. Most recently, events such as the US strikes on Hashdi Sabi and Turkey’s cross-border military campaigns against the so-called Syrian Democratic Forces (SDF) have fueled these discussions.
The existence of armed NSAs is certainly not a new phenomenon; as early as 1837 the ‘Caroline incident’ involved the use of a cross-border force by insurgents which created a rift between the USA and Great Britain. However, today the threat posed by the armed NSAs to the international system seems greater than ever before. Technological and military advancements have not only strengthened the states’ tight control on their territories, but also exponentially increased NSAs’ capacity for ameliorating their military activities.
Clearly, the proliferation of NSAs is a matter of the highest concern in the MENA region. Thus, as long as the armed NSAs’ ongoing military activities across the region are capable of impacting all our lives, the question of how to handle this phenomenon remains top of the agenda for the governments in the region. Another concern for these governments is the fact that the ‘atomization of sovereignty’, in favor of NSAs, has become a reality and the regional status quo underpinning the existing nation-states’ borders is being challenged and even crumbling. These NSAs challenge the existing boundaries, cross borders to fight against other states, occupy territories and establish their own forms of governance. We have even seen the emergence of a handful of autonomous regional entities across the region. In Syria, “even the most avid observer of Syrian affairs has lost track of the numbers of non- state actors in the country.”
Moreover, the NSAs and their transboundary military activities directly amount to a challenge to the current framework of international law. The question of the right of self-defense against the armed NSAs in the face of their large-scale transboundary attacks has recently been one of the central matters of debate for international lawyers.
THE ‘RIGHT OF SELF-DEFENSE’ DILEMMA
Traditionally, it has been accepted by international law doctrine that a state’s right of self-defense can be triggered only by armed attacks coming from other states. The International Court of Justice (ICJ) adopted this approach in the cases concerning; military and paramilitary activities in and against Nicaragua (Nicaragua v. US), armed activities in the territory of the Congo (DR of the Congo v. Uganda) and its advisory opinion on the legal consequences of the construction of a wall in the occupied Palestinian territory. Article 51 of the United Nations (UN) Charter is the main legal source of the right of self-defense in contemporary international law, however, it does not specify who can be the perpetrator of such armed attacks, thus leaving room for debate.
There is little doubt that the reason for this is the fact that almost all of the international armed conflicts which occurred before the UN Charter came into effect, were between states. Nevertheless, towards the end of the 20st century a shift in the traditional approach of the charter emerged in parallel with the emergence of the new realities on the ground and threats against states. Technological and military advancements have remarkably enhanced the destruction capacities of the armed NSAs. Such actors have become more capable of employing unconventional warfare methods against state military forces, even carrying out indiscriminate attacks which make no distinction between civilians and combatants. The September 11 attacks in particular were a breaking point in terms of attempts to assert an up to date and dynamic interpretation of the right of self-defense in international law to respond efficiently to the armed NSAs conducting cross-border terrorist attacks.
International lawyers are now loosely divided into two camps on the new approach that is challenging the traditional interpretation and practice. On the one hand, states cannot be expected to “simply undergo private attacks without having the right to defend themselves by using force against the home bases of these groups and their accomplices. On the other hand, state sovereignty is and remains one of the basic pillars of international law ”  and the principle of territorial integrity of states shall not be undermined. This is why Sir Ian Brownlie, a well-respected British international lawyer and firm advocate of the traditional approach, said that the concept of armed attack must mean only the grave forms of use of force under the auspices of governments.
UP TO DATE APPROACHES
Against the backdrop of the perceived need for an up to date and dynamic interpretation of the right of self-defense vis-à-vis the traditional approaches, various suggestions have been proposed, such as resorting to the concept force majeure to justify the use of force by states against armed NSAs located in the territories of other states. However, one suggestion has gained more endorsement than others: ‘The unable and unwilling doctrine’. Accordingly, when a state is unable or unwilling to prevent its territory being used by armed NSAs as a base for launching attacks against other states, the victim state would be permitted to use its right of self-defense as long as the other requirements are met. That is to say, the territorial state may exercise due diligence, but it may nonetheless be unable to prevent the attack coming from an NSA based in its territory. Additionally, even if that territorial state is neither complicit, actively supporting that NSA for its armed attack, nor failing to exercise due diligence to prevent the NSA from using its territory to mount an armed attack against another state, that state would still incur the consequences of the NSA’s attack if the victim state were to exercise its right of self-defense.
The USA argued the unable and unwilling doctrine when it initiated a military intervention against Al-Qaida in Afghanistan’s and Pakistan’s territories following the September 11 attacks, without taking into account the consent of the territorial states. Similarly, the USA, United Kingdom, France and Iraq evoked the unable and unwilling doctrine for their cross-border military campaign against the so-called Islamic State of Iraq and the Levant (DAESH) in 2015. The most important factor for the advocates of the unable and unwilling doctrine is, as mentioned above, the absence of the explicit specification of possible perpetrators of armed attacks in Article 51 of the UN Charter. Moreover, the dissenting opinions of some ICJ judges in the aforementioned landmark cases corroborated the new approaches.
In fact, support for the unable and unwilling doctrine from the international community had been very weak until the September 11 attacks. There were a few exceptions such as events involving Israel, the USA,  Portugal,  Russia,  Turkey  and Iran , but most of these were condemned either by the UN Security Council or General Assembly. However, once the threat of international terrorism began to be profoundly felt by the international community, opposition to the unable and unwilling doctrine started to trail off. For example, the US strikes on the so-called Al Qaida bases and armories in Afghanistan and Sudan did not become subject to any UN General Assembly resolutions, unlike similar strikes in the 1980’s. Likewise, Turkey’s cross-border operations against Partiya Karkeren Kurdistane (PKK) bases in Northern Iraq in 1997 were not even condemned by the UN Security Council, despite the reproach of the Iraqi government.
Another important ground for the advocates of the unable and unwilling doctrine are the UN Security Council Resolutions 1368 and 1373 concerning the US military intervention in Afghanistan. It is argued that the permissive language of these resolutions confirmed the fact that the traditional scope of the right of self-defense in international law had been altered. Moreover, the explicit support given by NATO , Organization of American States (OAS) and the EU for the US’ actions further strengthened this argument.
In recent years, the unable and unwilling doctrine has been adopted by several states in the context of the battle against some armed groups such as DAESH and the PKK which have gained strong footholds in Syria and Iraq due to the regional turmoil 2011-12. States such as Canada have joined the international coalition against DAESH based on the unable and unwilling doctrine. In the same vein, Turkey clearly stated the same justification in its letters to the UN regarding its cross-border military interventions against the imminent threat posed by DAESH and the PKK, namely Operation Euphrates Shield, Olive Branch and Peace Spring.
Perhaps it is still too early to claim that most of the international community have endorsed the unable and unwilling doctrine, given that at a meeting in September 2016 the Non-Aligned Movement (NAM), a loose grouping of 120 States, stated that “the NAM has long resisted any attempts to expand the right of self-defense, or any other unilateral use of force against sovereign states.” However, in the face of the growing power and capacities of the armed NSAs, this doctrine seems to be rapidly gaining ground both in the practice of the prominent states and international law doctrine. As such, it is an approach which fits with the customary obligation of states to prevent the use of their territories by non-state elements in a way which threatens the security of other states.
States suffering from attacks by armed NSAs operating within the territories of other states which are unable or unwilling to halt NSA activities are left with very few options as to how to respond. It is not realistic for them to prioritize the sovereignty of any other state over their own national security and remain inactive. Indeed, there does not seem to be a state which is under a transboundary threat of the armed NSAs but still keeps its distance from the unable and unwilling doctrine. Therefore, since the beginning of the 21st century we have been witnessing an increase in the number of states which adopt a broad interpretation of the right of self-defense by moving away from its traditional definition.
If the international law system and doctrine cannot adapt itself into this reality, then the powerful and prominent members of the international community -including many MENA regional powers such as Turkey, Iran and Israel- will probably turn their backs on the obsolescent framework of international law for the sake of assuring their national security against the grave threats posed by the armed NSAs surrounding them. Such a situation would be a great demise of international law itself. Therefore, the merits of the unable and unwilling doctrine must be acknowledged. Instead of a total denial, the main focus must be on drawing plausible boundaries for this doctrine in order to prevent it being too “open-ended and effectively destroying the overarching rule prohibiting the use of force in international relations.” Hence, beside the already existing requirements such as the threshold of gravity of an armed attack in scale and effect, the imminence of the threat, promptness and proportionality of the response, the implementation of the unable and unwilling doctrine can be restricted with some other mechanisms and norms to be established between states. It is crucial to ensure that the unable and unwilling doctrine is used for defensive, rather than punitive purposes.
It must be underlined that most of the cases at the center of the unable and unwilling doctrine debates are in, or somehow related to, the MENA region. It is also important to realize that the use of the right of self-defense by states against armed NSAs has gained recognition in the regional security order of the MENA. One of the main reasons being that the unable and unwilling doctrine seems to be the most effective way for nation states in the region to confront the emanating proxy wars across the MENA. Against the backdrop of these proxy wars, the “myth of the sacrosanctity of non-intervention principle” must be put aside at times and the unable and unwilling doctrine must come into play as a deterrent force.
 Galip Dalay, “Break-up of the Middle East: Will we see a new regional order?”, Middle East Eye 14 September 2017, https://www.middleeasteye.net/big-story/break-middle-east-will-we-see-new-regional-order
 Tom Ruys and Sten Verhoeven,”Attacks by private actors and the right of self-defence,” Journal of Conflict & Security Law 10, no. 3 (2005): 289-320. www.jstor.org/stable/26294397.
 For details see: Raphaël Van Steenberghe, “Self-Defense in Response to Attacks by Non-state Actors in the Light of Recent State Practice: A Step Forward?”, Leiden Journal of International Law , 2010, Vol. 23; Ceren Zeynep Pirim, “Devletlere Atfedı̇lemeyen Sı̇lâhlı Saldırılara Karşı Meşru Müdafaa: Uluslararası Hukukta Sınır Ötesı̇ Operasyonun Hukukı̂ Zemı̇nı̇”, TAAD, 2019, Vol. 40.
 Israel hinged on the right of self-defense in its cross-border military attacks against the Beirut Airport in 1968, the aircrafts belong to Lebanon and Libya respectively in 1973 and 1986, Palestinian Liberation Organization (PLO) within the Tunusian territory in 1985.
 Alongside the US’ military interventions subsequent to September 11 Attacks, the bombardment of Libya in 1986 in response to the bombing of a night club in Berlin by some terrorists supposedly supported by the Qaddafi regime was one of the early instances of the use of the right of self-defense by the USA against armed irregular forces.
 See: Security Council Resolution of 28 July 1969, UN Doc. S/RES/268.
 In 2002, during the Second Chechen War, Russian raids targeted a Chechen population in the Pankisi Gorge, situated in a part of Georgia.
 Since 1983 Turkey has been relying on the unable and unwilling doctrine for its cross-border military interventions against PKK, see: Tom Ruys, “ Quo Vadit Jus ad Bellum?: A Legal Analysis of Turkey’s Military Operations Against the PKK in Northern Iraq”, MJIL, 2008, 9 (2); also see: Letter from Turkey referring to the letter from the Libyan Arab Jamahiriya (S/1995/566) and stating that under existing circumstances, Turkey’s use of measures seen as imperative to its security cannot be regarded as a violation of Iraq’s sovereignty, UN Doc. S/1995/605, 14 July 1995.
 Iran has hit the headquarters of People’s Mujahedin of Iran located in Iraq starting from mid-1990’s.
 For example: Security Council Resolution of 4 October 1985, UN Doc. S/RES/573; General Assembly Resolution of 20 November 1986, UN Doc. A/RES/41/38.
 For example, see: Identical letters from the Chargé d’affaires a.i. of the Permanent Mission of Turkey to the United Nations addressed to the Secretary-General and the President of the Security Council, UN Doc. S/2018/53, 20 January 2018; UN Security Council, Letter dated 9 October 2019 from the Permanent Representative of Turkey to the United Nations addressed to the President of the Security Council.
 Jutta Brunnée and Stephen J Toope, “Self-defence against non-state actors: are powerful states willing but unable to change international law?” International and Comparative Law Quarterly 67, no. 2 (2018): 263–86. https://www.cambridge.org/core/journals/international-and-comparative-law-quarterly/article/selfdefence-against-nonstate-actors-are-powerful-states-willing-but-unable-to-change-international-law/9256C35660E40D89BAFC9A9282DCC161/core-reader