International Law: Self-Defense under Customary Law and UN Charter

This report delves into the intricacies of self-defense within the framework of international law, examining both customary international law and the provisions outlined in the United Nations Charter. It begins by establishing the inherent right of self-defense for states and individuals, then proceeds to compare and contrast the two primary sources of law governing this right. The report explores the Caroline test, a cornerstone of customary law, and analyzes the UN Charter's Article 51, which addresses self-defense in the context of armed attacks. Key differences and similarities between these legal sources are highlighted, including the scope of interpretation and the procedures required. The report further investigates the interpretation and application of the self-defense doctrine, including pre-emptive actions and responses to non-state actors, such as insurgent groups. The report then explores the Republic of Nicaragua vs. United States of America (1986) case. Ultimately, the report offers a comprehensive overview of the legal complexities surrounding self-defense in the modern world, encompassing contemporary debates and challenges. The report also includes a discussion on the contemporary debates and the actions of non-state actors in the context of self-defence.

International Law and the use of Force
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Contents
Introduction................................................................................................................................3
Customary International law regarding self defence.................................................................3
United Nations Charter and its role in self defence...................................................................4
Difference between the above two sources................................................................................5
Interpretation and application of Doctrine of self defence.........................................................7
Contemporary debates and act of non-state actors.....................................................................8
Conclusion................................................................................................................................10
Reference List..........................................................................................................................11
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Introduction
The right of self defence is inherent to all people and state. It is only natural that if a state is
attacked it is their responsibility to take reverberating steps by the state against the attack.
The reactive steps are not taken first it comes as a response hence there cannot be any
violation associated with it. This report evaluates the doctrine of self defence which is widely
present in the customary international law and also in the United Nation Charter. There are
issues raised when there is non-state actor conducting an act of violence. Mostly the insurgent
group in the modern geo-political environment serves as the non state actors. The states tend
to refuse responsibility yet retaliation cannot wait on that ground. The aspects of self defence
in such contexts are going to be evaluated in this report.
Customary International law regarding self defence
One of the main sources of international law is customary international law. This source of
law has gained recognition from all the primary bodies of international law like the
international court of justice, international jurists, United Nations and the members of the
United Nations as well. Thus the Customary international law can be considered as one of the
primary sources of law that governs the international issues. The states that are part of
international conventions are bound to include their regulations. The interventions that are
often done by some states for resolving possible situations of war on another state might
often enough not be justified under the formed treaties, they are mostly justified by the
customary international law. There is an increase support regarding interventions that are
done for moral purposes for preventing war situation justified by international law. At the
same time the customary international law has been accused to have been misused in several
occasions as well1. Examples of strong international economies taking use of the gaps in
international legislation for exploiting weaker economies can also be seen.
The example of customary international law’s doctrine of self defence can be seen in the
Caroline incidence. A US citizen who attacked British Colony in Canada is the incidence of
the Caroline test. This customary international law has been given a shape through the
Caroline test. The case suggested that there are three conditions in which the act of self
defence is justified these three conditions are; there should be a necessity of immediate self
1 AGGESTAM L, 'Introduction: Ethical Power Europe?' (2008) 84 International Affairs
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defence because of the presence of ‘imminent threat’, there should be no time for deliberation
before the act and lastly the act should not go out of proportion and should be limited only to
the defence of the cause of possible harm2. These are the clauses that have been stated by the
US secretary of state during the incidence to the British Authorities. These lines have been
considered as the true actual description of the concept of customary rights of self defence.
The concept of ‘imminent threat’ can be considered as one of the key standards in which
international customary law judges the action of self defence. The concept of ‘imminent
threat’ has been further described by Daniel Webstar as the kind of threat that is not only
immediate but which is likely to cause extensive harm in case of delay for deliberation or
inaction. The right of self-defence is not codified in the act of law thus it can be considered
that it has been left open for interpretation however the Caroline Test has provided with a
definitive guideline that can validate the act of self defence. The Customary International law
has gained this definitive aspect in the year 1837. The customary international law supports
the delay of action when there is no imminent threat and there is scope for gaining evidence.
In general the concept of humanity gives recognition to the right of self defence. The
international customary law has majorly taken into consideration the aspect of pre-emptive
self defence. The principle of self defence has pre-existed the Caroline test. But the
significance of the Caroline Test in the customary international law has only provided with a
certain amount of guideline by which the international acts of self defence can be evaluated.
The three key parameters of the doctrine is necessity, which can be defined as the immediate
need for taking action because of the imminence of the state. Second aspect is the
proportionality which suggests that the authorities need to restrict their power and ensures a
balance. Third aspect is purpose which can be defined as there should be consistency between
the objective and the result.
United Nations Charter and its role in self defence
The United Nation Charter adopted in 1945. Self defence is dealt with in the Chapter VII of
the Charter of United Nation. The Article 51 of Chapter VII that each member of the United
Nation has the right to act in self defence an inherent right in case they face an attack. The
Charter has also stated that the Security Council is responsible for the defence of the attack
2 Conk G and others, 'OTHERWISE' (Blackstonetoday.blogspot.com, 2019)
<https://blackstonetoday.blogspot.com/2011/02/> accessed 10 April 2019
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but until and unless there is an act defence that is planned and executed by the Security
Council there is no provision in the charter that bars the state under attack from taking actions
of self defence. The Article also states that it is the responsibility of the member state to
inform the Security Council regarding the nature of the attack and the action that is taken by
it in self defence. The Security Council holds the authority at any point of time to take actions
that can restore peace and security. The Article 51 is formed for the preservation of rights
when there is a case of armed attack but apart from that the article 2 (4) of the United Nations
Charter bans any other form of act of self defence3. Self defence can be defined as a counter
measure against attack for restoration of peace. The article 51 lays down specific situation
when an armed attack occurs. The article 51 does not state any definitive measure in case of
an armed attack. Armed attack can be defined as a use of military force in the international
boundary of a state. However as mentioned it is only restricted to particular situations. The
article 51 can be considered as one of the charters that can be considered as an exception to
the rest of the acts of the charter. Most of the articles of the UN Charter forbid any form of
violence or armed acts. But the article 51 only states that the issue of self defence while under
attack is of paramount importance and thus all the states who are the member of the UN
charter holds the right to act is self defence. But the state in the meantime is not liable to face
violence without taking any step on their part to defend themselves. Thus the Charter in its
article 51 allows the members states to take the required actions at the time of attack. The
base content of the charter forbids the use of force. The charter was formed post the second
world war and the intent of the formation of the charter was to ensure that the mass
destruction that is caused by the second world war can be restricted by the formation of an
international body which is likely to take control of violence conducted by one country on
another. There is one notable aspect that has been mentioned in the article 51 which states
that a state that has faced attack can act in self defence unilaterally that is alone or with the
help of some allied countries that is collective defence. The article 51 of the UN charter has
been provided with two types of interpretation the ‘strict’ interpretation or ‘broad’
interpretation. The strict interpretation tries to restrict to the defensive meaning of the charter
whereas the broad interpretation tries to extend the meaning of the article for extending its
implementation.
3 Guiora A, 'Anticipatory Self-Defence And International Law--A Re-Evaluation' (2008) 13 Journal of Conflict and
Security Law
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Difference between the above two sources
There are several differences between the customary international law and the United Nation
Charter regarding the action of self defence. The customary international law provides higher
scope of interpretation and action as there are aspects of morality that are also considered in
it. But the United Nation Charter articles are open to interpretation. However as the Caroline
test there are three particular case scenarios that are specified when action can be taken but
there is no such particular scenario that has been defined for taking actions. The Charter
however has not mentioned any particular scenario or evaluation of scenario which is going
to consider as an attack. The customary international law does not provide any specific
procedures that are to be undertaken post an action in the form of defence is done4. But under
the United Nation Charter once a country is faced with an attack they have to report to the
Security Council regarding the threat that has been faced by them and the actions that are
being taken in defence. The UN charter restricts the retaliation to the group or individual
involved in armed attack. There is one other clause in the UN charter that can be given an
unrestricted explanation. The UN charter has stated that the defence that is to be formed by
the country under attack can be either unilateral that is done by the state that has faced the
attack directly or the defence can be done in collaboration that is there is scope for the
country which is under attack to gather allies for the purpose of defence.
It is important to mention that the number of similarities that is present in both of these
sources is also significant. The customary international law and the United Nation Charter
have developed the right of defence on the ground that each country has an inherent right to
defend them when under attack5. Both these sources recognise the fact that the attack can be a
physical one in which arms are used or it can be in the nature of threat. The threat aspect has
been accepted in the form of pre-emptive defence in the international customary law and the
United Nation Charter has also accepted the self initiated defence conducted by the state in
particular specific cases. There are some areas in which the scope is more for violence in the
customary international law and in other cases the UN charter tend to provide more scopes.
4 'Home – Parliament Of Australia' (Aph.gov.au, 2019) <http://www.aph.gov.au/> accessed 10 April 2019
5 Savaş C, 'States Of War Since 9/11 Terrorism. Sovereignty And The War On Terror, Alex Houen (Dir.), 2014, New
York, Routledge, 267 P.' (2015) 46 Études internationales
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Interpretation and application of Doctrine of self defence
In case of The Republic of Nicaragua vs. The United States of America (1986) the
international court of justice, CIJ ruled in favour of Nicaragua on the basis of a
determination through an interpretation of Article 51 of the charter. The Customary
international law recognizes the right of self defence on behalf of a country that has
experienced armed attack or has experience some kind of threat similar to armed attack the
doctrine has support for the customary international law so an inferential support can be
established. The customary international law accepts the inherent right of self defence and
pre-emptive action of self defence on behalf of a country provided the country has faced a
threat which can be an armed attack or equivalent to armed attack. Thus both the law justifies
the armed action taken by Nicaragua against the armed activities of the rebels. The ICJ find
that the military insurgency carried out by United states in Nicaragua led to the violation of
both the sources of laws of Article 5 1 of the charter of united nation and the customary
international law and establishes the fact that the military action undertaken by Nicaragua for
its self defence was justified6. The Article 51 of UN Charter automatically accepts the fact
that there is a customary international law pre-existing to the formation of the treaty. The fact
of “inherent right” that is not supposed to be violated by the contents of the charter as stated
in the charter is an evidence of acceptance for customary international law. One more
commonality among the two is the fact that they are covering the exact same issue. The two
sources of law exist with each other and there is no necessary contradiction among them7.
The focus of the debate is regarding the right of a state to defend itself in case they are
attacked by non- state actors. One of the key propagators of theories regarding the right of the
state to self defend is of Daniel Bethlehem. Bethlehem summarises 16 principles which is
aimed at further evaluation of the debate. The principles have been generated by Bethlehem
after detail discussion with foreign ministry, legal military advisors and ministry of defence.
The principles state the right of state in case of actual or imminent threat of armed attack.
Bethlehem in his sixteen principles states that a state has a right to defend itself but can only
exercise it as a last resort. The limit of reaction should be decided on the scale of the extent of
action. An attack, imminent or actual should have series of threatening activities involving
arms and ammunition. The attack can be a result of planning, threatening or actual
6 (Icj-cij.org, 1986) <https://www.icj-cij.org/files/case-related/70/070-19860627-JUD-01-00-EN.pdf> accessed
18 April 2019
7 'International Court Of Justice: Case Concerning Military And Paramilitary Activities In And Against Nicaragua
(Nicaragua V. United States)' (1986) 25 International Legal Materials
7

perpetuation. The reaction should be against these activities. Proper judgement regarding the
imminence of the armed attack should be done. It is the responsibility of the state to make
sure that the state is not used as a ground for practising insurgency. A state should take
permission from another state in case a non state actor is using the territory of the state as a
ground for its camp. But this formality is not applicable when the state is helping the non
state actor. The formality of consent is also not applicable in case the state is incapable of
handling the non state actors. The nature of the consent can be operational, expressed,
implied or ad hoc8. The principles that has been stated by Bethlehem is not prejudiced by the
UN Charter or the International customary law, right of self defence or any other issues of
wrongful act.
On 14th February 2019 there was a suicide attack conducted in Pulwama District of Jammu
and Kashmir which resulted in the death of more than 40 members of the Indian army. This
can be considered as one of the severe attacks and its impact has also been severe in the
country in terms of loss of life and peace. Post the attack the terrorist group Jaish-e-
Mohammad a terrorist organisation took the credit of the attack. After the attack there was a
series of air strikes conducted by the Indian and the Pakistani Air force. The question in this
case is whether this attack can be considered as an act of self defence. The evaluation of the
act of self defence has to be done both on the doctrine of self defence in the customary
international law and the United Nations Charter.
First of all the evaluation has to be done on the ground of the Caroline doctrine of the
Customary International Law. The first question according to this doctrine is whether there
was an existing threat. Conducting terrorist attack on a state is always filled with the
possibility that it can be repeated. The lack of action on the part of the State can impact its
defence as there can be even more subsequent attacks. The second question is whether there
was chance for deliberation or the reaction had to be made immediately. In this case
considering the fact that it is an act of terrorism the time of deliberation can result in loss of
more life and asset of the country and third question is whether the return attack was only
against the perpetrator that is whether the reaction was limited by the consideration of the fact
that there is only one group that has claimed the violation and the defence action will be
limited to the return attack on that particular group9. This is one aspect that will need detailed
information regarding the attack that was undertaken by the Indian air force in reaction to the
terrorist attack. The published reports have suggested that the Indian air force has targeted
8 Bethlehem D, 'Remarks By Daniel Bethlehem' (2009) 103 Proceedings of the ASIL Annual Meeting
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their attack on the intelligence report regarding the camp locations of the Jaish e Mohammad.
The nature of the attack was surgical strike and not a war. Surgical strike can be defined as a
form of attack where the camps of the non state actors are being targeted instead of targeting
the state in which the non state actors are residing.
In terms of the evaluation of the incidence in terms of United Nation Charter it can be stated
that the Charter allows a country to take unilateral or collective action in case of armed
attack. Pre-emptive self defence has been provisioned in the charter. In this particular step the
action that has been taken by Jaish e Mohammad can be considered under an armed attack.
Thus the retaliation that has been done by India can be justified. Again it is important to state
at this point that the nature of retaliation that is done by the government is surgical strike.
They have not taken any direct action against the government of Pakistan rather they have
located the places of terrorist camps and surgically attacked in those locations. India took
unilateral action against Jaish e Mohammad by attacking on their location of camps. At the
same time as it has been mentioned before there are some customary steps that have to be
taken by the Members of United Nation post the action of self defence. These steps involve
providing the Security Council with detailed information regarding the act of violation that is
done by the perpetrator and the actions that are taken in response10. This duty has also been
fulfilled by the Indian Government so it can be stated that even according to the UN Charter
the actions that has been taken by the government of India can be justified.
In the attack of September 11 the steps that were taken by the Government of USA can be
considered as similar to that of India. The Government of USA post the attack on World
Trade centre decided in conducting an attack by the means of air strike on the recognised
terrorist agency which claimed their involvement with the attack. The nature of self defence
that was undertaken by the US government was collaborative in nature as they involved the
Government of UK as well in their retaliation attack.
9 Mitchell R, 'Anthea Roberts, Is International Law International?, Oxford: Oxford University Press, 2017, 420 Pp, Hb
£25.99.' (2018) 81 The Modern Law Review
10 'Meetings Coverage And Press Releases' (Un.org, 2019) <http://www.un.org/press/en> accessed 10 April 2019
9

Contemporary debates and act of non-state actors
There is however a critical issue that arises when the perpetrators are non state actors. The
moral and ethical question that has been raised during the attack of 11 September in the world
trade centre and also recently during the self defence retaliation that was done by the
Government of India. The causes of threat in both these cases are terrorist organisations like
Al Qaeda and Jaish e Mohammad.
Al Qaeda is a terrorist organisation that has been started by Osama-Bin-Laden in the year
1988. The location from where the operation of this terrorist organisation is Iraq. However Al
Qaeda has been banned in the state of Iraq. The state in which the operation of this
organisation takes place has been stated as inefficient by some of the academicians. Even
there have been such claims that are made by the government of Yemen which stated that Al
Qaeda operated from its geographical landmass because of the inefficiency of the
counterinsurgency measures of the government.
Similarly the Jaish e Mohammad is an organisation that can be considered as armed non state
actor operating in some of the countries because of their incapability to take measures for
eradicating such activity from their states. The Government of Pakistan has also banned the
organisation in the year 2002.
But the government of USA has raged a full scale war in Iraq and Afghanistan for fighting
against the terrorist organisation. The loss of life and property in those countries in which war
has taken place can be considered as a significant amount. The retaliation that has been done
by the government of India in response to the actions of Jaish e Mohammad can be
considered as much limited in nature11. There has been no extensive loss of life and property
in Pakistan. The government of Pakistan however has cited the ground that the militant group
is banned in their country in self defence.
This can be considered as an ethical dilemma. But there are certain insurgency groups that are
being state funded by some of the states and yet they claim no part in the insurgency
activities. The insurgency groups serve the vested interest of the state and yet it becomes
difficult to blame the state for the activities that are conducted by the insurgent groups. Thus
11 Trapp K, 'Back To Basics: Necessity, Proportionality, And The Right Of Self-Defence Against Non-State Terrorist
Actors' (2007) 56 International and Comparative Law Quarterly
10

the decision of not attacking a state only on the ground that they have banned any insurgent
groups cannot be enough. The ethical dilemma in this situation is paramount. The only
method of dealing such situation is asking for cooperation from the state in which there is
report of insurgent activities12. The response has to be made immediate in case of denial or
delay it is important for the country that has been faced with militant activities to respond
immediately to the attack as it is the basic inherent right of the state.
12 Savaş C, 'States Of War Since 9/11 Terrorism. Sovereignty And The War On Terror, Alex Houen (Dir.), 2014, New
York, Routledge, 267 P.' (2015) 46 Études internationales
11

Conclusion
In conclusion it can be stated that the customary international law have clauses that supports
the claim of self defence if faced with an attack. The United Nation Charter in its Article 51
gives the right to retaliate when being attacked. There are differences in the nature of
retaliation suggested in the two sources. The attack that was conducted by Jaish e
Mohammad is one of the key issues of self defence that has been discussed in the
international forum. The act of self defence by India in the form of surgical strike has been
commended by most of the international bodies. However there is a question of ethical
dilemma in case of non state actors like Jaish e Mohammad. They are not owned by any of
the state but can create problem because they can cause armed actions against a state. The
state in which their camps are located should take responsibility for the group. But regardless
of the fact that whether a state takes responsibility of the insurgent group or not the country
which is being attacked has the right to retaliate as it is their inherent right.
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Reference List
Journal
AGGESTAM L, 'Introduction: Ethical Power Europe?' (2008) 84 International Affairs
Bethlehem D, 'Remarks By Daniel Bethlehem' (2009) 103 Proceedings of the ASIL Annual
Meeting
Eleftheriadou M, 'Elements Of ‘Armed Non-State Actors’ Power: The Case Of Al-Qaeda In
Yemen' (2014) 25 Small Wars & Insurgencies
Guiora A, 'Anticipatory Self-Defence And International Law--A Re-Evaluation' (2008) 13
Journal of Conflict and Security Law
'International Court Of Justice: Case Concerning Military And Paramilitary Activities In And
Against Nicaragua (Nicaragua V. United States)' (1986) 25 International Legal Materials
'Meetings Coverage And Press Releases' (Un.org, 2019) <http://www.un.org/press/en>
accessed 10 April 2019
Mitchell R, 'Anthea Roberts, Is International Law International?, Oxford: Oxford University
Press, 2017, 420 Pp, Hb £25.99.' (2018) 81 The Modern Law Review
Philp M, 'Janet Polasky,Revolutions Without Borders: The Call To Liberty In The Atlantic
World' (2016) 9 Britain and the World
Savaş C, 'States Of War Since 9/11 Terrorism. Sovereignty And The War On Terror, Alex
Houen (Dir.), 2014, New York, Routledge, 267 P.' (2015) 46 Études internationales
Trapp K, 'Back To Basics: Necessity, Proportionality, And The Right Of Self-Defence
Against Non-State Terrorist Actors' (2007) 56 International and Comparative Law
Quarterly
Website
'Home – Parliament Of Australia' (Aph.gov.au, 2019) <http://www.aph.gov.au/> accessed 10
April 2019
Conk G and others, 'OTHERWISE' (Blackstonetoday.blogspot.com, 2019)
<https://blackstonetoday.blogspot.com/2011/02/> accessed 10 April 2019
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