Self-Defence Against Non-State Actors: Reconceptualising the Legality of the 'Unwilling or Unable' Test in Light of the Doctrine of Necessity in International Law

AuthorSuraj D Bhaskaran
PositionLLM (LSE) '21. BPTC (Gray's Inn) '20. BA (Hons) in Politics and Law (University of Kent) '19
Self-Defence Against Non-State Actors
Self-Defence Against Non-State Actors:
Reconceptualising the Legality of the ‘Unwilling or
Unable’ Test in Light of the Doctrine of Necessity in
International Law.
Suraj D Bhaskaran*
The ‘unwilling or unable’ test is a real-world challenge that has the potential to make a
mockery of the cornerstone of modern international law in Article 2(4) of the UN Charter.
The increasing prevalence of unattributable armed attacks by N SAs provides an opportunity
for powerful victim States to expand the notion of the inherent right of self-defence through the
‘unwilling or unable’ test, without any real thorough basis to their reasoning. To complicate
matters further, the dangers of State silence in the face of the unwilling or unable justification
from primarily powerful Western S tates seeking to invoke self-defence, may end up playing into
the hands of proponents of the ‘unwilling or unable’ test. This potentially contrib utes to ‘norm
entrepreneurship’ and the shaping of international law in their favour through the expansion of
the law of self-defence to incorporate the test itself. Despite the uncertainty surrounding the
legality of the test, the fact rem ains that the legitimation of predatory force against primarily
weaker host States in the Global South by primarily powerful victim States in the Global
North cannot continue and has to be addressed in order to avoid the abuse of the test in the
name of self-defence. The principle of necessity provides this foundation and is the key to
engaging S tates in a discourse that seeks to bring the ‘unwilling or unable’ test into greater
compliance with the jus ad bellum regime. This paper refines Deeks’ test, using the notions of
reasonableness and objectivity un der the principle of necessity, and aims to contribute to the
debate on the ‘unwilling or unable’ doctrine by clarifying the possible practical application of the
test in order to strike as close a balance between the inherent right of self-defence on one hand,
and State sovereignty and territorial integrity on the other.
* LLM (LSE) ‘21. BPTC (Gray’s Inn) ‘20. BA (Hons) in Politics and Law (University of
Kent) ‘19. The author warmly thanks Dr Devika Hovell for her guidance and
enthusiasm whilst supervising this work.
LSE Law Review!
Vol. VII
Article 2(4) of the UN Charter is explicit in prohibiting the use of force
against States by requiring Mem ber States to ‘refrain in their international
relations from the threat or use of force against the territorial integrity or
political independence of any State, or in any other manner inconsistent with the
Purposes of the United Nations’.1 This prohibition is held widely to be
peremptory in nature and is often referred to as the ‘cornerstone’ of modern
international law.2 However, as per Article 51 of the UN Charter, this do es not
impair the inherent right of States to use individual or collective self-defence if
an armed attack occurs against them.3 At a cursory glance, this seems to
preserve an inter-State reading of the UN Charter. However, this type of reading
has eroded over the last few decades, as a result of greater discussion on
whether armed attacks can be carried out by non-State actors (NSAs) and
whether States are able to use force in self-defence against NSAs in other
countries. This paper is structured into six sections. Section II will briefly take a
look at both these questions through interpreting Article 51, along with ICJ
jurisprudence and State practice, before ev entually asserting that NSAs can
mount an armed attack and self-defence is indeed permissible against NSAs
when an armed attack by those NSAs is attributable to a State. This Section will
further explore whether self-defence is permissible against NSAs through the
‘unwilling or unable’ test when an armed attack by those NSAs is not attributable
to a State, before resting on th e fact that although Article 51 and ICJ
jurisprudence do not preclude this, there does not seem to be enough State
practice and opinio juris to permit the practice as part of customary international
However, this does not put an end to the conversation on the ‘unwilling or
unable’ test. Despite its controversial legality, the fact remains that the ‘unwilling
1 Charter of the United Nations (adopted 26 June 1945, entered into force 24 October
1945) 1 UNTS XVI (UN Charter) art 2(4).
2 Christian Tams, ‘The Use of Force Against Terrorists’ (2009) 20 European Journal of
International Law 359.
3 UN Charter (n 1), art 51.
4 Kevin Jon Heller, ‘The Absence of Practice Supporting the “Unwilling or UnableTest’
(Opinio Juris, 17 February 2015) < unable-unwilling-
imagination/#:~:text=Simply%20put%2C%20there%2 0is%20simply,against%20a%20n
on%2Dstate%20actor> accessed 25 February 2022.

To continue reading

Request your trial

VLEX uses login cookies to provide you with a better browsing experience. If you click on 'Accept' or continue browsing this site we consider that you accept our cookie policy. ACCEPT