top of page
  • Anandita Srivastava

Use Of Force Against The Non-State Actors (NSAs)

This article is authored by Anandita Srivastava, a third-year student at the National Law University, Jodhpur.

The attack of 9/11 drew unparalleled attention towards the terror activities caused by the NSAs and it led to global support to curb the terror activities. Article 2(4) of the United Nations (UN) Charter states that all Members shall refrain from the threat or use of force against the ‘territorial integrity’ or ‘political independence’ of any state,[1] and this general rule has two exceptions: first, Article 51 of the Charter that states the inherent right of ‘individual or collective self-defence’ if an armed attack occurs against a Member of the UN, and second, Article 42 of the Charter, granting the power to the Security Council to take such action to maintain international peace.[2] Furthermore, the Declaration on Principles of International Law Concerning Friendly Relations and Co-operation among States in accordance with the UN Charter, stipulates that no State or group of States has the right to intervene, directly or indirectly, for any reason whatever, in the internal or external affairs of any other States.[3]

Two views of states:

One view of scholars and states such as China, Brazil, Sri Lanka, and Mexico, is that using force against NSAs in the territory of another state, for the purpose of self-defence, shall be subject to the ‘consent’ of the state concerned.[4] This traditional view believes that no state can intervene in a sovereign’s internal affairs under the cloak of “counter-terrorism”, or use force arbitrarily in the name of “preventive self-defence”.[5]

DRC v Uganda

In the case of Armed Activities on the Territory of the Congo, even though the court found that, by actively extending support to irregular forces operating on the territory of the DRC, Uganda had violated Article 2(4) of the Charter. The International Court of Justice’s (ICJ) decision briefly talked about a State’s right to use force for its self-defence against the NSAs, but it failed to specify the ‘circumstances’ under which that right to use force can be materialised. In particular, ICJ held that because the attacks carried out by anti-Ugandan rebels operating from the DRC are not attributable to the DRC, Uganda has no right to use force in self-defence against the DRC.[6] This meant that the right to use force in self-defence against an attack by NSAs only applies where the attack is attributable to the State in whose territory defensive force is being used.[7] However, this view seemed to have lost its popularity post the horrific terrorist attacks of 9/11.

The opposite view states that Article 2(4) is not violated because the victim state aims to neutralise only the NSA located in the host state and in the process, it does not interfere with either the host state’s ‘territorial integrity’ or its ‘political independence’. For instance, Australia, Estonia, Netherlands, and United Kingdom acknowledge that when NSAs are engaged in an actual or impending armed attack and the host state is ‘unwilling’ or ‘unable’ to stop the attack coming from its territory, then it may exercise its right to individual or collective self-defence against those NSAs on the host territory.[8] Netherland, concurring with the Australian viewpoint adds that the use of force, in furtherance of right to self-defence, ought to be restricted solely to countering the armed attack by the NSA, without exceeding that scope.[9]

Israel v Uganda

The aforementioned opposite view came in vogue in 1976, when Israel mounted a rescue operation at Entebbe airport, in response to the hijacking of an aircraft bound for Tel Aviv and diverted to Uganda. Its defensive measures were directed only at the persons responsible for the hijacking and hostage crisis and Israel specifically claimed that its rescue operation was not directed against Uganda. This hinted at their reasoning to declare that the use of force deployed was not to violate the general rule of Article 2(4) of the Charter, precisely, Uganda’s territorial integrity or political independence, rather it was targeted against the NSA only.[10]

India’s Balakot Strikes of 2019

India justified its Balakot Strikes on similar lines. India’s action was termed as a non-military pre-emptive action which was specifically targeted at the JeM camp and careful of avoiding any civilian casualties.[11] Thereby, claiming that the general rule as laid down under article 2(4) was not violated by India while targeting an NSA- JeM in the host country-Pakistan.

Doctrine of Necessity, Proportionality, and Anticipatory Self-defence.

The balancing mechanism between the right of self-defence against NSAs and the right of States’ territorial integrity lies within the customary international law (CIL). It is the requirement that a ‘use of force’ be ‘necessary’ and ‘proportionate’.[12] As per the Caroline case, Article 51 of the Charter only recognises the state’s ‘inherent’ right of self-defence against an armed attack,[13] which can be exercised if the threshold of ‘necessity’ is satisfied.  This case is said to have established the CIL for self-defence against NSAs (though this view is heavily contested).[14] The threshold of necessity is satisfied when the attack is ‘instant’, ‘overwhelming’, ‘leaving no choice of means’, and ‘no moment for deliberation’. This gives a justification to the victim state to exercise its ‘inherent’ right of self-defence.[15] Moreover, the self-defence should not be ‘excessive’ or ‘unreasonable’.[16]

Unwilling and unable doctrine

The attacks of 9/11 led to a change in the attitude of the international community. With the doctrines of ‘necessity’, ‘proportionality’, and ‘anticipated self-defence’ coming in usage, the ‘unwilling and unable’ doctrine emerged. This doctrine means that if the host state actively counters the terrorist activities of NSAs, or takes all possible measures to prevent such terrorists from using its territory for attacks, then the use of force by the victim State against NSAs situated in the host State, will not be categorized as a necessary use of force.[17] Furthermore, the substitution (and imposition) of the victim State’s views on how to deal with the terrorist threat emanating from the host State’s territory for those of the host State, amounts to an illegal intervention.[18] However, this doctrine being a CIL has been widely debated among the international law community.[19]

Israel v Tunisia

In 1985, Israel bombed the Palestine Liberation Organization’s (PLO) headquarters in Tunisia. Israel asserted a right to use force in self-defence in Tunisian territory against Tunisia as it had knowingly harboured the PLO and allowed it complete freedom of illegal action from its soil. Israel took the justification plea of the right of self-defence directly against NSAs. Israel argued that its use of force was ‘necessary’ and ‘proportionate’ given the ‘unwilling or unable doctrine’. Interestingly, this was not an acceptable or even a popular view in the year 1985, and thus, states did not address Israel’s novel legal argument and instead denied that Tunisia, even if it did harbour the PLO, could be held responsible for its conduct.[20]

However, as aforementioned, the attacks of 9/11 changed the international attitude towards terrorism and the right of self-defence against NSAs as UNSC resolutions 1368[21] and 1373[22] were passed, condemning terrorist attacks that breach international peace and security and which called for international support to hold the perpetrators of the attacks accountable. These two resolutions nonetheless failed to explicitly authorize the use of force against NSAs. So, the states were again left to find refuge under the broad exception of self-defence under Article 51 to justify their counter attacks.

USA v Al Qaeda

USA went one step further to describe its counter-actions as a ‘war on terror’ rather than just as self-defence.[23] Despite many states still questioning the legitimacy of USA’s breach of international rules in its unilateral war against terror, the world community rightly condemned the terrorist attacks as unforgivable crimes against humanity. This showcases the change in attitude of the international community with regard to self-defence against NSAs.[24]

USA, in its letter to UNSC dated 7th October 2001, informed that [it had] initiated actions in the exercise of its inherent right of individual and collective self-defence following the armed attacks that were carried out against it on 9/11/2001. The attack and the ongoing threat to USA and its nationals posed by the Al-Qaeda organization have been made possible by the decision of the Taliban regime to allow the parts of Afghanistan that it controls to be used by this organization as a base of operation.[25] Thereafter, the ‘unwilling and unable’ doctrine got its biggest champion in the form of USA’s war on terror.

Israel-Hamas war

Israel-Palestine is not a newly founded conflict, but the recent attack by Hamas on 7th October, 2023, has led to a counter-attack by Israel and thereafter a full-fledged war against Hamas. In this context, President Joe Biden, in a White House statement stated, “I made clear to Prime Minister Netanyahu that we stand ready to offer all appropriate means of support to the Government and people of Israel. Terrorism is never justified. Israel has a right to defend itself and its people”.[26] Biden’s statement clarifies that if Israel asks for US’s aid under the inherent right of ‘collective self-defence’, US would grant full support. Furthermore, US along with the leaders of France, Germany, Italy, and United Kingdom released a joint statement expressing their united support to Israel and unequivocal condemnation of Hamas and its appalling acts of terrorism.[27]  


The situation in Gaza keeps getting worse, such that the General Assembly has recently urged an immediate humanitarian ceasefire, demanding unhindered aid to Gaza. It called for humanitarian access, the release of captives, and stressed the impact on vulnerable groups.[28]  Emphasising restraint, it urged a peaceful resolution based on UN resolutions and international law.[29]

The UN Security Council is widely considered to have endorsed and even invited the USA’s position that the 9/11 terrorist attacks gave rise to the right to use force in self-defence against NSAs.[30] In the post-Al Qaeda world, the 2001 Afghan military campaign remains the only case in which the international community accepted a state’s right to use force in self-defence against both the NSA and the host state.

The view that a state must obtain consent from the host state before using its right to self-defence against the NSA is out of date, but the more recent strategy of subtly claiming that the victim state merely seeks to ‘neutralise’ the NSA—as in the case of India—or that the host state is ‘unable or unwilling’ to stop the terror attacks on its own—as in the case of the USA—has gained traction. The most intrinsic feature of this view is that the use of force in furtherance of self-defence has to be ‘proportional’, and not excessive or unreasonable in nature.[31] 

During the ongoing Israel-Hamas conflict, Israel’s alleged commission of war crimes and breach of the ‘proportionality’ principle,[32] while receiving support from the US, challenges the UN’s aims to secure international peace. This scenario might prompt an opposing and a third viewpoint: the legitimacy of any action taken in self-defence against an NSA initiating an attack.

Therefore, in the ongoing war against Hamas, the question before the international community is whether Israel is acting in self-defence against an NSA or acting as reprisal (which is illegal under international law). And whether Israel has, nonchalantly (as it is supported by the US, a veto power in the Security Council), breached the ‘proportionality’ requirement under the principle of self-defence.[33]


[1] Article 2(4) of the UN Charter.

[2] Chapter VII (precisely Article 51 & 42) of the UN Charter.

[3] Declaration on Principles of International Law concerning Friendly Relations and Cooperation among States in accordance with the Charter of the United Nations, GA Res 2625 (XXV), 24th Oct, 1970.

[4] Adil Ahmad Haque, Self-Defence Against Non-State Actors: All Over the Map. Insights from UN Security Council Arria-Formula Meeting (Mar. 24th, 2021), Just Security.

[5] See Remarks by Ambassador GENG Shuang at the Open Arria Formula Meeting “Upholding the collective security system of the UN Charter: the use of force in international law, non-state actors and legitimate self-defence”,,consent%20of%20the%20state%20concerned.

[6] Case Concerning Armed Activities on the Territory of the Congo (Democratic Republic of the Congo v Uganda), (Dec 19th, 2005) [DRC v Uganda] ¶147.

[7] Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) ICJ Reports (1986) at 14.

[8] Adil Ahmad Haque, supra note 4.

[9] Id. 

[10] Security Council official records, 1939th meeting, (July 9th, 1976) ¶121,

[11] Statement by Foreign Secretary on 26 February 2019 on the Strike on JeM Training Camp at Balakot, Ministry of External Affairs, Government of India (Feb. 26th, 2019),

[12] Back to Basics: Necessity, proportionality, and the right of self-defence against non-state terrorist actors, International and Comparative Law Quarterly, at 142.

[13] Matthew C. Waxman, The Caroline Affair in the Evolving International Law of Self-Defence, Lawfare (Aug. 28th, 2018),

[14]See Srinivas Burra, Use of Force as Self Defence against Non-State Actors and TWAIL Considerations: A Critical Analysis of India’s State Practice, Asian Yearbook on International Law 24 (2018) at 111-12.

[15] Id  at 112. 

[16] Malcom N. Shaw, International Law 1131 (2008).

[17] Supra note 12 at 147.

[18] Supra note 3.

[19] Elena Chachko, Ashley Deeks, Which States Support the ‘Unwilling and Unable’ Test?, (Oct.10th, 2016),

[20] Supra note 12 at 149.

[21] Resolution 1368 (2001) / adopted by the Security Council at its 4370th meeting, on 12 September 2001. 

[22] Resolution 1373 (2001) / adopted by the Security Council at its 4385th meeting, on 28 September 2001. 

[23] Javaid Rehman, International Law, US Foreign Policy and Post-9/11 Islamic Fundamentalism: The Legal Status of the ‘War on Terror’, Nordic Intl Law J. 77 (2008) at 87–103.

[24] Id. 

[25] Letter dated 7 October 2001 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, UN Doc S/2001/946. See also Christopher Greenwood, International Law and the War against Terrorism (2002) 78 Intl. Affairs at 301, 311-12.

[26] Israel-Gaza updates: Israeli forces preparing for ‘wide range of offensive plans’, (Oct. 17th, 2023),

[28] Supra note 15.

[29] General Assembly Adopts Resolution Calling for Immediate, Sustained Humanitarian Truce Leading to Cessation of Hostilities between Israel, Hamas, TENTH EMERGENCY SPECIAL SESSION, UNGA/12548 (OCT. 27, 2023).

[30] Supra note 12 at 151.

[31] Shaw, supra note 17.

[32] Damning evidence of war crimes as Israeli attacks wipe out entire families in Gaza, Amnesty International (Oct 20, 2023). 

[33] Supra note 15.

90 views0 comments


bottom of page