Literature Notes – Week 6
Gleider Hernandez, International Law – Chapter 13, Enforcement short of force
13.1 Introduction: self-help in international law
13.2 Reprisals in international law
13.2.1 What are reprisals
13.2.2 The prohibition on armed reprisals
13.3 Retorsion
13.4 Countermeasures
13.4.1 What are countermeasures?
13.4.2 Substantive conditions on countermeasures
13.4.3 Countermeasures and third states
13.4.4 Countermeasures and international organisations
13.4.5 So-called ‘economic coercion’
13.5 Sanctions
13.5.1 What are sanctions?
13.5.2 Sanctions in United Nations practice
13.5.2.1 Sanctions and the Security Council
13.5.2.2 Types of sanctions in practice
13.5.2.3 Limits on the imposition of sanctions
, Gleider Hernandez, International Law – Chapter 14, Use of force and collective security
14.1 Introduction: the role of law in constraining international violence
International law’s role has developed incrementally to allocate the legitimate use of violence
between different international actors, rather than a blanket prohibition on force. The 1919
Covenant of the League of Nations marked a shift in the relationship between law and force. A
further landmark was the 1928 ‘Kellogg-Briand Pact’, parties to which agreed to renounce war as an
instrument of national policy in their relations with one another.
14.2 The Charter prohibition on the use of force
14.2.1 Article 2(4) of the UN Charter
Article 2(4) of the UN Charter has established a prohibition against a state unilaterally threatening or
using force against another state, which is widely considered to be a principle of customary
international law, as established in the Nicaragua case. However, the interpretation of the
prohibition on the use of force remains controversial, with certain terms requiring further scrutiny.
14.2.2 Use of force in ‘international relations’
The use of ‘force’ is generally understood to encompass armed force used directly or
indirectly against another state, as illustrated in Nicaragua, where the various indirect
actions of the USA were categorised as forcible. The use of force does not encompass the
imposition of sanctions, boycotts or embargoes, or other forms of so-called ‘economic
coercion’, though the General Assembly has called into question the legality of such acts in
the Friendly Relations Declaration.
The prohibition on the use of force in ‘international relations’ raises questions regarding the
categorisation of conflicts, as it leaves open the use of force within states.
14.2.3 The meaning of ‘threat or use of force’
The notion of ‘threat’ was addressed by the ICJ in its advisory opinion on the Legality of the Threat or
Use of Nuclear Weapons, finding that a “signalled intent to use force if certain events occur” was
understood to constitute a threat under Article 2(4), provided that the envisaged use of force would
itself be unlawful under that provision.
14.2.4 Preserving the territorial integrity and political independence of a state
During the Cold War, vigorous debates occurred concerning the prohibition in Article 2(4) against the
use of force ‘against the territorial integrity or political independence of any state’, as some states
interpreted this as permitting limited uses of force, which to them did not violate territorial integrity
or political independence. However, this was decisively rejected in the merits phase of Nicaragua
and by the Eritrea-Ethiopia Claims Commission, which concluded that recourse to force would violate
international law even in situations where the state resorting to force had a valid claim to territory.
14.3 The right to self-defence and Article 51 of the Charter
14.3.1 The scope of the right of unilateral self-defence
There is a significant exception in international law to Article 2(4) embodied in Article 51 of the
Charter, according to which a state may use force unilaterally in order to defend itself. Certain
scholars contend that Article 51 is an exhaustive formulation of the conditions under which self-
defence may be exercised, and should be narrowly construed, whereas others take a broader
interpretation of self-defence as an ‘inherent’ customary law right, allowing for its exercise in
situations beyond those envisaged by the Charter.
14.3.2 Necessity and proportionality
Though there are debates about the scope of the right to self-defence, there is near universal
consensus that force used in self-defence is not limitless, but must be both necessary and
proportionate, something which the ICJ has repeatedly confirmed in cases such as Nicaragua. As
Gleider Hernandez, International Law – Chapter 13, Enforcement short of force
13.1 Introduction: self-help in international law
13.2 Reprisals in international law
13.2.1 What are reprisals
13.2.2 The prohibition on armed reprisals
13.3 Retorsion
13.4 Countermeasures
13.4.1 What are countermeasures?
13.4.2 Substantive conditions on countermeasures
13.4.3 Countermeasures and third states
13.4.4 Countermeasures and international organisations
13.4.5 So-called ‘economic coercion’
13.5 Sanctions
13.5.1 What are sanctions?
13.5.2 Sanctions in United Nations practice
13.5.2.1 Sanctions and the Security Council
13.5.2.2 Types of sanctions in practice
13.5.2.3 Limits on the imposition of sanctions
, Gleider Hernandez, International Law – Chapter 14, Use of force and collective security
14.1 Introduction: the role of law in constraining international violence
International law’s role has developed incrementally to allocate the legitimate use of violence
between different international actors, rather than a blanket prohibition on force. The 1919
Covenant of the League of Nations marked a shift in the relationship between law and force. A
further landmark was the 1928 ‘Kellogg-Briand Pact’, parties to which agreed to renounce war as an
instrument of national policy in their relations with one another.
14.2 The Charter prohibition on the use of force
14.2.1 Article 2(4) of the UN Charter
Article 2(4) of the UN Charter has established a prohibition against a state unilaterally threatening or
using force against another state, which is widely considered to be a principle of customary
international law, as established in the Nicaragua case. However, the interpretation of the
prohibition on the use of force remains controversial, with certain terms requiring further scrutiny.
14.2.2 Use of force in ‘international relations’
The use of ‘force’ is generally understood to encompass armed force used directly or
indirectly against another state, as illustrated in Nicaragua, where the various indirect
actions of the USA were categorised as forcible. The use of force does not encompass the
imposition of sanctions, boycotts or embargoes, or other forms of so-called ‘economic
coercion’, though the General Assembly has called into question the legality of such acts in
the Friendly Relations Declaration.
The prohibition on the use of force in ‘international relations’ raises questions regarding the
categorisation of conflicts, as it leaves open the use of force within states.
14.2.3 The meaning of ‘threat or use of force’
The notion of ‘threat’ was addressed by the ICJ in its advisory opinion on the Legality of the Threat or
Use of Nuclear Weapons, finding that a “signalled intent to use force if certain events occur” was
understood to constitute a threat under Article 2(4), provided that the envisaged use of force would
itself be unlawful under that provision.
14.2.4 Preserving the territorial integrity and political independence of a state
During the Cold War, vigorous debates occurred concerning the prohibition in Article 2(4) against the
use of force ‘against the territorial integrity or political independence of any state’, as some states
interpreted this as permitting limited uses of force, which to them did not violate territorial integrity
or political independence. However, this was decisively rejected in the merits phase of Nicaragua
and by the Eritrea-Ethiopia Claims Commission, which concluded that recourse to force would violate
international law even in situations where the state resorting to force had a valid claim to territory.
14.3 The right to self-defence and Article 51 of the Charter
14.3.1 The scope of the right of unilateral self-defence
There is a significant exception in international law to Article 2(4) embodied in Article 51 of the
Charter, according to which a state may use force unilaterally in order to defend itself. Certain
scholars contend that Article 51 is an exhaustive formulation of the conditions under which self-
defence may be exercised, and should be narrowly construed, whereas others take a broader
interpretation of self-defence as an ‘inherent’ customary law right, allowing for its exercise in
situations beyond those envisaged by the Charter.
14.3.2 Necessity and proportionality
Though there are debates about the scope of the right to self-defence, there is near universal
consensus that force used in self-defence is not limitless, but must be both necessary and
proportionate, something which the ICJ has repeatedly confirmed in cases such as Nicaragua. As
