Problem 4 IEL
Learning objecti ves
1. Under which conditions does international law allow the use of force and when are
states allowed to use force?
The international rules and principles governing force constitute a vital component of the
international law of coexistence.
International law distinguishes between:
- Jus ad bellum: Rules regulating when and for what purpose a state may use force
against another state.
- Jus in bello: Rules relating to how military hostilities must be conducted.
In this chapter we discuss jus ad bellum.
General prohibition against the use of force
Prohibition against the threat or use of force we find in customary international law and in
the UN Charter art. 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.”
Read in conjunction with:
- Purposes of the UN (art.1 UN Charter)
o Maintain international peace and security.
- Principles of the UN (art.2 UN Charter)
o Sovereign equality of all Member States.
- Relationship with international dispute settlement – art. 2(3) UN Charter
Use of armed force below this threshold: violation of the principle of non-intervention
and exercise of physical power as violation of sovereignty.
Only use of force directed at territorial integrity and political independence is covered by the
prohibition. The better view is that the prohibition covers all uses of force.
Also customary international law. Both sets of rules co-exist parallelly, without one rule
superseding the other *Nicaragua: ICJ stated that the use of force is regulated both in
the UN Charter and in customary international law and that the content of the two sources
of law is not identical in all relevant aspects.
Using force on the basis of valid consent from a host state is not prescribed by art. 2(4).
The legitimacy of consent to the use of force seems to be influenced by the extent to which
the consenting government is seen as representative of the will of the population and/or if
the government has previously been recognized by the international community and not yet
been replaced by another entity.
Interferences that fall below the threshold for constituting force under art. 2(4)
A state’s interference in another state does not constitute force under art. 2(4) may still
violate international law.
1. The principle of territorial sovereignty dictates that a state may not exercise its
physical power in any form in the territory of another state. A violation of that
principle constitutes a breach of sovereignty.
The obligation to respect the sovereignty of other states is reflected in art. 2(1).
, 2. An interference that falls below the threshold of force may also violate the principle
of non-intervention, according to which a state may not intervene in the
international affairs of another state. Also reflected in art. 2(1).
The prohibition against interventions consists of two elements:
- An intervention aimed at (an attempt to coerce; only acts that are intended to cause
a change in policy in another state that can violate the principle)
- A matter in which each state is permitted to decide freely.
*Nicaragua: ICJ found that US support to the military and paramilitary activities of the
Nicaraguan contras, including financial support, training, weapons supply and intelligence
and logistical support, violated the principle of non-intervention.
There are only two legally valid exceptions to the general rule (art. 2(4) UN Charter):
1. Art. 42: UN Security Council Authorization
2. Art. 51: Individual of Collective self-defence
International force should be used only in the common interests of the international
community.
The right to self-defence
Art. 51: the right to self-defence is triggered when an armed attack occurs.
There appears to be overall agreement that a state may be entitled to resort to anticipatory
self-defence against an expected assault when the threat is imminent.
1. Such a right must be interpreted narrowly and only relied on in exceptional
circumstances.
2. Anticipatory self-defence must be distinguished from so-called pre-emptive of
preventive self-defence, which is not exercised in response to an imminent threat.
Preventive self-defence clearly violates art. 51. In response to 9/11, the US proclaimed a
right to preventive self-defence, according to which the US would act against emerging
threats before they are fully formed. Outside the US the doctrine found little support.
To be lawful, self-defence must be necessary and proportionate.
- Necessity: a state must ascertain if other, more peaceful, means or redress are
available before using force in self-defence.
- Proportionality: requires the victim state to strike a fair balance between the armed
attack and the measures taken to stop it. To assess the proportionality of use of
force, one must identify the legitimate aim of the use of force and then determine if
the force used is excessive in order to achieve that aim.
Requirement of immediacy: The response to an armed attack should be undertaken either
while the attack is still in progress or at least not too long thereafter.
Before resorting the use of force against a private actor in another state, the victim state
should request the host state to intervene and stop the private actor’s activities.
The scope of the right is one of the most contested areas of international law.
*Nicaragua: the ICJ stated that the terms testifies to the existence of a right to self-defence
under customary international law that exists alongside article 51.
The right to self-defence is triggered by an ‘armed attack’. To qualify, an attack must be of a
certain intensity. The ICJ distinguished between the ‘most grave forms of the use of force’
and ‘other less grave forms’.
Learning objecti ves
1. Under which conditions does international law allow the use of force and when are
states allowed to use force?
The international rules and principles governing force constitute a vital component of the
international law of coexistence.
International law distinguishes between:
- Jus ad bellum: Rules regulating when and for what purpose a state may use force
against another state.
- Jus in bello: Rules relating to how military hostilities must be conducted.
In this chapter we discuss jus ad bellum.
General prohibition against the use of force
Prohibition against the threat or use of force we find in customary international law and in
the UN Charter art. 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.”
Read in conjunction with:
- Purposes of the UN (art.1 UN Charter)
o Maintain international peace and security.
- Principles of the UN (art.2 UN Charter)
o Sovereign equality of all Member States.
- Relationship with international dispute settlement – art. 2(3) UN Charter
Use of armed force below this threshold: violation of the principle of non-intervention
and exercise of physical power as violation of sovereignty.
Only use of force directed at territorial integrity and political independence is covered by the
prohibition. The better view is that the prohibition covers all uses of force.
Also customary international law. Both sets of rules co-exist parallelly, without one rule
superseding the other *Nicaragua: ICJ stated that the use of force is regulated both in
the UN Charter and in customary international law and that the content of the two sources
of law is not identical in all relevant aspects.
Using force on the basis of valid consent from a host state is not prescribed by art. 2(4).
The legitimacy of consent to the use of force seems to be influenced by the extent to which
the consenting government is seen as representative of the will of the population and/or if
the government has previously been recognized by the international community and not yet
been replaced by another entity.
Interferences that fall below the threshold for constituting force under art. 2(4)
A state’s interference in another state does not constitute force under art. 2(4) may still
violate international law.
1. The principle of territorial sovereignty dictates that a state may not exercise its
physical power in any form in the territory of another state. A violation of that
principle constitutes a breach of sovereignty.
The obligation to respect the sovereignty of other states is reflected in art. 2(1).
, 2. An interference that falls below the threshold of force may also violate the principle
of non-intervention, according to which a state may not intervene in the
international affairs of another state. Also reflected in art. 2(1).
The prohibition against interventions consists of two elements:
- An intervention aimed at (an attempt to coerce; only acts that are intended to cause
a change in policy in another state that can violate the principle)
- A matter in which each state is permitted to decide freely.
*Nicaragua: ICJ found that US support to the military and paramilitary activities of the
Nicaraguan contras, including financial support, training, weapons supply and intelligence
and logistical support, violated the principle of non-intervention.
There are only two legally valid exceptions to the general rule (art. 2(4) UN Charter):
1. Art. 42: UN Security Council Authorization
2. Art. 51: Individual of Collective self-defence
International force should be used only in the common interests of the international
community.
The right to self-defence
Art. 51: the right to self-defence is triggered when an armed attack occurs.
There appears to be overall agreement that a state may be entitled to resort to anticipatory
self-defence against an expected assault when the threat is imminent.
1. Such a right must be interpreted narrowly and only relied on in exceptional
circumstances.
2. Anticipatory self-defence must be distinguished from so-called pre-emptive of
preventive self-defence, which is not exercised in response to an imminent threat.
Preventive self-defence clearly violates art. 51. In response to 9/11, the US proclaimed a
right to preventive self-defence, according to which the US would act against emerging
threats before they are fully formed. Outside the US the doctrine found little support.
To be lawful, self-defence must be necessary and proportionate.
- Necessity: a state must ascertain if other, more peaceful, means or redress are
available before using force in self-defence.
- Proportionality: requires the victim state to strike a fair balance between the armed
attack and the measures taken to stop it. To assess the proportionality of use of
force, one must identify the legitimate aim of the use of force and then determine if
the force used is excessive in order to achieve that aim.
Requirement of immediacy: The response to an armed attack should be undertaken either
while the attack is still in progress or at least not too long thereafter.
Before resorting the use of force against a private actor in another state, the victim state
should request the host state to intervene and stop the private actor’s activities.
The scope of the right is one of the most contested areas of international law.
*Nicaragua: the ICJ stated that the terms testifies to the existence of a right to self-defence
under customary international law that exists alongside article 51.
The right to self-defence is triggered by an ‘armed attack’. To qualify, an attack must be of a
certain intensity. The ICJ distinguished between the ‘most grave forms of the use of force’
and ‘other less grave forms’.
