USE OF FORCE

Evaluate the principles of international law regarding the use of force by one state against
another. Citing legal authority and relevant examples, show the extent to which such
principles remain relevant to contemporary international challenges.
Introduction & Background
Under international law principles, States can neither threaten to use force nor use force in their
international relations. The principles of international law regarding the use of force by one state
against another are enshrined in the United Nations Charter (1945)1, particularly in Articles
2(4)2, 513, and 42 as well as in customary international law and binding treaties such as in
Article 53 of the Geneva Conventions on the Law of Treaties4 which makes it a peremptory
norm .(A peremptory norm is a norm from which States cannot depart).
Before the 1945 and before the advent of the United Nations, States were free to decide on
whether to wage war or not on other states.The only form of restraint on States was a moral
consideration relating to whether the war was “just” or whether the war would fulfil certain
philosophical, religious, and ethical requirements.

Consequently this culminated into a series of wars, States waged brutal wars against one another
without legal constraints such as World War 1 in 1914. The League of Nations was the first
attempt made at regulating the use of force. This wasn't successful as within just a short period
there was World War II. Because of the massive destruction caused by these wars, there was
need order to ensure peace and regulate use of force against other states hence the United
Nations Charter of 1945 that set out principles providing guidelines to member states on the
use of force.Over time, these principles have evolved but remain central to the regulation of
armed conflict in the modern international legal framework.

This essay is therefore intended to show an evaluation of the relevant principles regarding
use of force of one State against another , the legal authority, and their applicability to
contemporary international challenges.

BODY
After World War II there was a need to maintain peace and security hence the formation of The
UN Charter that sought to prohibit the use of force and acts of aggression by States. Article 1

1 UN Charter 1945
2 Article 2(4). “All Members shall 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."
3 Article 51 of the UN Charter. “..Nothing in the present Charter shall impair the inherent
right of individual or collective self-defense if an armed attack occurs against a Member of
the United Nations..."
4 Geneva Convention on The Law of Treaties (VCLT) of the UN Charter emphasizes this by
stating the purpose of the Charter as to include;“to maintain international peace and security…
to take effective collective measures for the prevention and removal of threats to the peace, and
for the suppression of acts of aggression…” As earlier noted above, Article 2(4) of the UN
Charter sets out the principle of prohibition of use of force. It emphasizes that "all Members
shall 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." This prohibition reflects the post-World War II
commitment to prevent the recurrence of aggressive war and the protection of sovereign
equality among states. Under this provision, the unilateral use of force is generally prohibited
except under certain circumstances, such as self-defense or Security Council authorization.

5 This position was evident in the International Court of Justice (ICJ) decision in Nicaragua
v. United States5.The pronouncements of the ICJ are of central importance with regard to the
interpretation of use of force.he ICJ was called on to categorize the various actions of the USA
aimed at the overthrow of the government of Nicaragua. It was held that not only the laying of
mines in Nicaraguan waters and attacks on Nicaraguan ports and oil installations by US forces
but also support for the opposition forces – the contras – engaged in forcible struggle against
the government could constitute the ‘use of force’. The arming and training of the contras
involved the unlawful use of force against the government of Nicaragua. However it was noted
that the mere supply of funds by the USA didn’t in itself amount to a use of force, but could
constitute unlawful intervention. Therefore the court clarified on what amounts to use of
force ,threats and aggression against another State.It also reaffirmed the centrality of the
prohibition of force in international law, holding that any use of force by a state not authorized
by the UN Charter is unlawful. The court stressed that self-defense must be proportionate and
necessary and that intervention in internal affairs such in the case of support for insurgencies is
also prohibited.
Therefore Article 2(4) prohibits force and does not only encourage States to renounce war. The
use of “shall refrain‟ in that provision: this is a command and not a plea.
Secondly, in addition to actual force, Article 2(4) also prohibits the threat of force and any use of
force so as to maintain World peace and security.
Despite the strict prohibition against the use of force under Article 2(4), the Charter permits
certain exceptions to the rule. This happens incase of use of force in self-defense defence as
emphasized in Article 51 of the Charter, secondly,where there is use of force unauthorised by the
UN Security Council, commonly called collective security Nicaragua v. United States (1986)
and use of force against an enemy State as empasized in Article 107 Chapter VII of the charter of
the Charter.
In regards to self defense, Article 51 of the UN Charter provides exception to the prohibition on
the use of force by allowing a state to use force in self-defense if it is attacked. This kind of
defense is expected to be reasonable and is supposed to last until the Security Council takes
action to maintain or restore international peace and security. Where the Security Council
intervenes, there ceases to be self defence and ay attack now will be taken as an act of
aggression. Self defense is a right and any State has a right to defend itself ifit has beern
attacked.
The attack must have alrwady happened. The Article justifies self defense and not retaliation.
The attack must be continuous or likely to continue and in ensuring this, the matter has to be
reported to the Security Council. The right is both individual and collective and can be
exercised by the attacked state alone or the State can call on help from others.The right to self
defense and collective self defense was emphasized in the Nicaragua case. The court
emphasized that “...the State which is the victim of an armed attack which must form and
declare the view that it has been so attacked. There is no rule in customary international law
permitting another State to exercise the right of collective self-defence on the basis of its own
assessment of the situation. Where collective self-defence is invoked, it is to be expected that the
State for whose benefit this right is used will have declared itself to be the victim of an armed
attack…”The Court emphasized that the requirement of a request by the State which is the
victim of the alleged attack is additional to the requirement that such a State should have
declared itself to have been attacked. However important to note is that self defense is subject to
legal interpretation for example in case of Oil Platforms Article 107 of the UN Charter 8, the
ICJ held that the use of force in self-defense must be necessary, proportional, and in response to
an armed attack.
Further under self defense, the UN Security Council also recognizes anticipatory “self defense”
incase of imminent danger. The argument is that when confronted by an overwhelming sense of

danger, such as an imminent attack, States cannot afford to wait for an attack to occur before
they act. So, some States argue that, in those circumstances, they can act in anticipation of
an attack. This is what the notion of
1 “anticipatory self-defence‟ implies. It can also be referred to as the doctrine of preemptive
self- defense (striking first to prevent an imminent threat). It was evident in the UN Security
Council Resolution 678 Oil Platforms (2003) passed under Chapter VII of the UN Charter,
where it authorized the use of force following Iraq's invasion of Kuwait.This resolution
legitimized military action by a coalition of states.Similarly the U.S.-led invasion of Iraq10was
under the claim of preemptive self-defense against Weapons of Mass Destruction (WMDs).
The invasion had been widely criticized as a violation of international law however U.S.A
justified the attack under Article 51 with a pretext that there was fear of an imminent attack.
From the above we see that although use of force is prohibited under Article 2(4), in cases of self
defense, state can use some force in protecting itself.

Secondly another exeception as to when use of force can be permitted is when the Responsibility
to Protect (R2P)doctrine is applied.This comes as a way of humanitarian intervention.The
contemporary understanding of international law increasingly takes into account factors beyond
the traditional model of state sovereignty, especially regarding mass atrocities like genocide or
crimes against humanity. The Responsibility to Protect (R2P) doctrine, which emerged in the
early 2000s, claims that the international community has a duty to intervene when a State is
unable to safeguard its population from atrocities such as genocide, war crimes, or ethnic
cleansing.Therefore in such cases, use of force by other states can be permitted.For example the
ICJ and the UN Security Council have addressed humanitarian intervention through Resolution
197311 (2011), which authorized the use of force in Libya to protect civilians from the Gaddafi
regime. However, the application of R2P remains contentious, as evidenced by the criticism of
the intervention in Libya for exceeding the scope of the original mandate, raising concerns about
sovereignty, misuse of force, and regime change. The doctrine also raises concerns about
favoritism since in some cases states refuse to take action for example the” super powers” are

2 UN Security Council Resolution 678(1990)

3 U.S.A invasion of Iraq (2003)
4 Resolution (1973)( 2011)
blamed for the genocide in Rwanda12 since they didn't take action yet they were bound to under
the R2P doctrine.

The Changing Nature of Warfare and Contemporary Challenges

While the principles of international law on the use of force remain largely intact, contemporary
challenges have arisen that challenge the application of these principles. Among these
challenges are Cyber warfare, Unilateral Actions and Proxy wars, Autonomous weapons and
Drones among others. This have to an extent undermined the prevention of Use of force for
example;
In relation to Cyber Warfare,the rise of cyber warfare presents a new frontier in the use of
force. Although the Tallinn Manual13 offers guidance on applying existing international law to
cyber-attacks, it's still hard to determine whether such attacks were just mere threats or involved
use of force.in reality, Cyberattacks cause significant damage, loss of life and should in all
circumstances, be considered acts of force and thus triggering the right to self-defense. However
this is still a contentious issue since its not clear as evidenced in the recent Iran-Israel wars where
missiles are being released in each others spaces.
Simlarly in regards to Unilateral Actions and Proxy Wars, of late, States have increasingly
engaged in proxy wars and covert operations rather than direct military confrontation. The
involvement of states like the U.S., Russia, and Iran in Syria and Ukraine illustrates how states
may influence conflicts indirectly. This has raised a challeng on the traditional understanding of
the use of force since attacks are now indirect and so it gets hard for a victim State to decide on
what steps to take. Whether to act in self defense or to wiat for invasion.
Further more, there has been an increase in the use of Autonomous Weapons and Drone. This
has raised questions of accountability and compliance with international law especially in
regards to the use of force. The challenge is in ascertaining whter there is a potential threat
calling for anticipatory self defense or not. For example the use of drones by the U.S. in
countries like Pakistan, Yemen, and Somalia raises concerns about sovereignty violations,

5 1994 Rwanda, Genocide

6 The Tallinn Manual on the International Law Applicable to Cyber Warfare (2013)
 civilian casualties, and the legal basis for extraterritorial strikes. It undermines the sovereignty
and as thus raises a question of these are acts of aggression on such states or not.
From the above we see that with the emergency of new forms of aggression, there has been a
challenge in interpretation of use of force which differs from the traditional understanding as
emphasised in the Nicaragua case and thus raised contemptuous issues in when and when not
states can act in case they believe they are under attack or imminent danger.

Conclusion

The principles of international law governing the use of force, enshrined in the UN Charter,
remain relevant but increasingly contested in light of contemporary challenges such as cyber
warfare, humanitarian intervention, and the evolving nature of armed conflict. Legal authorities
like the ICJ, UN Security Council, and humanitarian law continue to play key roles in shaping
the application of these principles. However, the increasing complexity of modern warfare and
state behavior requires continuous adaptation of international law to maintain global peace and
security as ably discussed above.