HUMANITARIAN AND SECURITY LAW
LECTURE NOTES: JUS AD BELLUM
3. JUS AD BELLUM
1. Some Historical notions
2. The UN Charter: jus contra bellum
3. Self-defence
4. Force authorised by the Un Security Council
5. Humanitarian interventions (Responsibility to protect R2P)
6. Case study: Use of Force in Syria
7. Case study: Russia’s Invasion of Ukraine
3.1. INTRODUCTION
► Jus ad bellum has become an attempt to establish a jus contra bellum (a prohibition of war)
o However, states have a tendency to find ways to legitimise the use of force.
3.2. SOME HISTORICAL NOTIONS
► Bellum justum (Theory of the Just War), Thomas Aquinas → Under certain conditions, a war could be
justified.
o 1) Authority of a prince (not private violence/feud)
o 2) Just cause (enforcement of a right/self-defence)
o 3) Recta intention (no greed/revenge) → intention should be noble.
=>Such theories have popped up again.
► 18-19th century: abandonment of just/unjust wars: vital interests as justification
o No limits on the right of states to resort to war.
o Prevention/control of war: mainly through a “balance of power” system
► First, restrictions on freedom to resort to war.
o Self-imposed:
▪ Treaties guaranteeing States against attacks (e.g., Belgium, Switzerland)
▪ Non-aggression pacts (Germany-Russia)
o Third Hague Convention (1907): formal declaration of war/ultimatum with conditional
declaration of war
1
, HUMANITARIAN AND SECURITY LAW
LECTURE NOTES: JUS AD BELLUM
► First World War: change in attitude towards war.
► League of Nations (1919): No prohibition, but a cooling-off mechanism
o Submit matter to arbitration/judicial settlement/inquiry y by Council; war only permitted three
months after judgment/report Council.
► Kellog-Briand Pact (1928)
o Total ban of war for the solution of controversies.
o Terminology was avoided → The pact could not prevent WWII, but it influenced the UN
Charter.
► Stimson Doctrine (1932) – Stimson was the American Secretary of State who refused to recognise a
Japanese invasion.
o No recognition of situations resulting from aggression (Manchukuo, 1931)
▪ Cf. UNSC Res. 662 (1990): Iraqi annexation of Kuwait null and void
▪ Cf. also UNGA Res. 68/262 of 27 March 2014, ‘Territorial Integrity of Ukraine’: “Calls
upon all States, international organisations and specialised agencies not to recognise
any alteration of the status of the Autonomous Republic of Crimea and the city of
Sevastopol on the basis of the above-mentioned referendum and to refrain from any
action or dealing that might be interpreted as recognising any such altered status.” (but:
only 100 MS voted for; 11 voted against; 58 abstained; 24 were absent → a plain act of
aggression in 2014 had 58 abstentions to be condemned).
o A new lease of life for the Stimson doctrine? UNGA resolutions on the Russian invasion and
war in Ukraine 2022→ UNGA Res ES-11/1 of 2 March 2022, sponsored by 96 countries, 141
voting in favour, five against, 35 abstentions: “Reaffirming that no territorial acquisition
resulting from the threat or use of force shall be recognised as legal”;
▪ 1. Reaffirms its commitment to the sovereignty, independence, unity and territorial
integrity of Ukraine within its internationally recognised borders, extending to its
territorial waters;
▪ 2. Deplores in the strongest terms the aggression by the Russian Federation against
Ukraine in violation of Article 2 (4) of the Charter;
▪ 3. Demands that the Russian Federation immediately cease its use of force against
Ukraine and refrain from any further unlawful threat or use of force against any
Member State;
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, HUMANITARIAN AND SECURITY LAW
LECTURE NOTES: JUS AD BELLUM
▪ 4. It also demands that the Russian Federation immediately, completely and
unconditionally withdraw all of its military forces from the territory of Ukraine within
its internationally recognised borders
3.3 THE UN CHARTER: JUS CONTRA BELLUM?
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.”
► Meaning
o “Force” not “war”
o Also, the threat of use of force (military build-up for the war in Ukraine was a breach)
o But “against territorial integrity/political independence” … “or in any other manner
inconsistent with the Purposes of the UN”.--> leeway for interpretation
o Broad normative scope supported by the UNGA Friendly Relations Declaration (1970)
o But nothing on “non-international armed conflicts”: non-intervention principle → A gap is
looking at the conflicts existing today.
▪ Non-intervention principle (Friendly Relations Declaration) / non-interference in
domestic affairs (Art. 2(7) UN Charter) – highlighted within the Cold War period.
▪ Use of force upon invitation of government? – to what extent can the use of force be
justified when a government which is facing civil war (non-international violent conflict)
invites it?
• Tricky because it brings questions of legitimate governments– e.g., consider the
Russian Support of the Assad Regime in Syria.
o Ambiguities
▪ E.g., Intervention for a good cause (and as an ultimate remedy) – the NATO Kosovo
Intervention – not an imperialist purpose (against the territorial integrity), but one
which has at its core saving human lives.
▪ Creative interpretations of interventions can circumvent Art.2(4).
o Some American scholars have claimed that the provision has become obsolete because of the
growing threat of terrorism (“War on Terror”).
▪ Not the majority but used to justify military interventions.
3
LECTURE NOTES: JUS AD BELLUM
3. JUS AD BELLUM
1. Some Historical notions
2. The UN Charter: jus contra bellum
3. Self-defence
4. Force authorised by the Un Security Council
5. Humanitarian interventions (Responsibility to protect R2P)
6. Case study: Use of Force in Syria
7. Case study: Russia’s Invasion of Ukraine
3.1. INTRODUCTION
► Jus ad bellum has become an attempt to establish a jus contra bellum (a prohibition of war)
o However, states have a tendency to find ways to legitimise the use of force.
3.2. SOME HISTORICAL NOTIONS
► Bellum justum (Theory of the Just War), Thomas Aquinas → Under certain conditions, a war could be
justified.
o 1) Authority of a prince (not private violence/feud)
o 2) Just cause (enforcement of a right/self-defence)
o 3) Recta intention (no greed/revenge) → intention should be noble.
=>Such theories have popped up again.
► 18-19th century: abandonment of just/unjust wars: vital interests as justification
o No limits on the right of states to resort to war.
o Prevention/control of war: mainly through a “balance of power” system
► First, restrictions on freedom to resort to war.
o Self-imposed:
▪ Treaties guaranteeing States against attacks (e.g., Belgium, Switzerland)
▪ Non-aggression pacts (Germany-Russia)
o Third Hague Convention (1907): formal declaration of war/ultimatum with conditional
declaration of war
1
, HUMANITARIAN AND SECURITY LAW
LECTURE NOTES: JUS AD BELLUM
► First World War: change in attitude towards war.
► League of Nations (1919): No prohibition, but a cooling-off mechanism
o Submit matter to arbitration/judicial settlement/inquiry y by Council; war only permitted three
months after judgment/report Council.
► Kellog-Briand Pact (1928)
o Total ban of war for the solution of controversies.
o Terminology was avoided → The pact could not prevent WWII, but it influenced the UN
Charter.
► Stimson Doctrine (1932) – Stimson was the American Secretary of State who refused to recognise a
Japanese invasion.
o No recognition of situations resulting from aggression (Manchukuo, 1931)
▪ Cf. UNSC Res. 662 (1990): Iraqi annexation of Kuwait null and void
▪ Cf. also UNGA Res. 68/262 of 27 March 2014, ‘Territorial Integrity of Ukraine’: “Calls
upon all States, international organisations and specialised agencies not to recognise
any alteration of the status of the Autonomous Republic of Crimea and the city of
Sevastopol on the basis of the above-mentioned referendum and to refrain from any
action or dealing that might be interpreted as recognising any such altered status.” (but:
only 100 MS voted for; 11 voted against; 58 abstained; 24 were absent → a plain act of
aggression in 2014 had 58 abstentions to be condemned).
o A new lease of life for the Stimson doctrine? UNGA resolutions on the Russian invasion and
war in Ukraine 2022→ UNGA Res ES-11/1 of 2 March 2022, sponsored by 96 countries, 141
voting in favour, five against, 35 abstentions: “Reaffirming that no territorial acquisition
resulting from the threat or use of force shall be recognised as legal”;
▪ 1. Reaffirms its commitment to the sovereignty, independence, unity and territorial
integrity of Ukraine within its internationally recognised borders, extending to its
territorial waters;
▪ 2. Deplores in the strongest terms the aggression by the Russian Federation against
Ukraine in violation of Article 2 (4) of the Charter;
▪ 3. Demands that the Russian Federation immediately cease its use of force against
Ukraine and refrain from any further unlawful threat or use of force against any
Member State;
2
, HUMANITARIAN AND SECURITY LAW
LECTURE NOTES: JUS AD BELLUM
▪ 4. It also demands that the Russian Federation immediately, completely and
unconditionally withdraw all of its military forces from the territory of Ukraine within
its internationally recognised borders
3.3 THE UN CHARTER: JUS CONTRA BELLUM?
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.”
► Meaning
o “Force” not “war”
o Also, the threat of use of force (military build-up for the war in Ukraine was a breach)
o But “against territorial integrity/political independence” … “or in any other manner
inconsistent with the Purposes of the UN”.--> leeway for interpretation
o Broad normative scope supported by the UNGA Friendly Relations Declaration (1970)
o But nothing on “non-international armed conflicts”: non-intervention principle → A gap is
looking at the conflicts existing today.
▪ Non-intervention principle (Friendly Relations Declaration) / non-interference in
domestic affairs (Art. 2(7) UN Charter) – highlighted within the Cold War period.
▪ Use of force upon invitation of government? – to what extent can the use of force be
justified when a government which is facing civil war (non-international violent conflict)
invites it?
• Tricky because it brings questions of legitimate governments– e.g., consider the
Russian Support of the Assad Regime in Syria.
o Ambiguities
▪ E.g., Intervention for a good cause (and as an ultimate remedy) – the NATO Kosovo
Intervention – not an imperialist purpose (against the territorial integrity), but one
which has at its core saving human lives.
▪ Creative interpretations of interventions can circumvent Art.2(4).
o Some American scholars have claimed that the provision has become obsolete because of the
growing threat of terrorism (“War on Terror”).
▪ Not the majority but used to justify military interventions.
3
