Module 1 - Introduction
Law of Nations (until 1870)
International Law (post 1870) – a branch of law in force between or above the sovereign
states of the world
Sources of intl. law (as per ICJ Statute Article 38(1)):
o International conventions (=treaties)
o International custom, as evidence of a general practice accepted as law
o General principles of law recognized by civilized nations (arbitration,
adjudication)
o Judicial decisions (such as those of the ICJ) and the teachings of the most highly
qualified publicists – only as subsidiary means
The law of treaties
o Treaties are the most important sources of intl. law
o Treaty – international agreement concluded between states in written form and
governed by international law (1969 Vienna Convention on the Law of Treaties)
o Might also be called conventions, charters, pacts, accords (still treaties)
The subjects of international law
1. Sovereign states
Criteria apply: population, territory, effective govt., capacity to enter intl.
relations, recognition by other states
2. Intergovernmental organizations
UN, WTO, ITU, ATS, etc.
3. Other entities (open to debate whether subject)
Political factions, individuals, corporations
Might be beneficiaries on behalf of the state, instead of subjects
Dispute resolution – a basic function of international law. There are various methods:
1. Direct negotiation, diplomatic settlements
2. Mediation
A third party assists and mediates →leads to an agreement
3. Arbitration
An arbitrator or arbitral tribunal decides →leads to an award
4. Adjudication
An established court or tribunal hears and decides →leads to a judgment
5. War (historically)
Areas within and beyond sovereign jurisdiction
o Land
Sovereign territory (within)
Antarctica (beyond)
o The Seas
Territorial sea, narrow 12-mile strip along the coast of the sea (within)
The high seas (beyond territorial jurisdiction, flag state jurisdiction applies)
Contiguous zones, Exclusive Economic Zone, continental shelf (limited
jurisdiction)
Deep seabed (beyond)
, o Airspace (within)
o Outer space (beyond)
Positive Law vs Natural Law
o Natural law: law which is “out there” to be “discovered”
Strength: noble, appealing, just (human rights, sustainability, dignity)
Weakness: subjectivity (who decides?), indeterminacy (what does it
mean?)
o Positive law: man-made, written law
Strength: formal legitimacy, visibility and precision of content
Weaknesses: politics (hard to agree on hard issues), indeterminacy (words
may be bent in many ways)
Rules vs Facts
o The basic model of legal argumentation:
Rule ˄ Fact → Conclusion
International law functions in absence of legislators, sovereign authority, police force,
department of justice or prosecutors. Why?
o No incentive to break intl. law, as the states themselves make it
o Bureaucratic inertia – a civil servant who routinely inspects compliance will not
suddenly stop doing so.
o Reciprocity – if country A mistreats country B’s citizens, it can expect country B
to do the same to its own citizens.
o Unlike people, states are few and attached to their territory. Nobody wants to be an
international pariah.
Sanctions in international law (in case of noncompliance)
o Retorsion – actions taken by one state to express dismay with another state’s
actions, such as recalling ambassadors, breaking off diplomatic relations
o Inadimplenti non est adimplendum: if A violates a treaty, B may do the same.
o Self defence and collective security actions, such as sanctioning particular
individuals.
International law in international relations theory:
o Self-proclaimed realists view intl. law as largely irrelevant, as they view states as
seeking only power and to further their own interests
o Liberal institutionalists think that intl. law can be relevant to create certainty in
trade and investments, reduce transaction costs and benefit all parties involved.
o Constructivists see intl. law as helping construct society – concluding alliances,
channelling political dialogue.
, Module 2 - Antiquity and Ius Gentium
There have always been elements of “the law of nations”. Modern international law has its
early roots in the Roman ius gentium.
Forms of international law in early antiquity:
1. Treaties (typically boundary, peace or alliance treaties)
a. Contain binding obligations
b. Oaths and curses (enforcement)
c. Assurances of good faith
2. Diplomatic practices
a. Diplomatic envoys and their inviolability
b. Access to ports or places
c. Treatment of foreigners (merchants or otherwise)
d. The practice of Arbitration can be found in antiquity
3. Law and war
a. The distinction between war and peace
b. Formalities of war, war as a legal procedure
c. A distinction between public enemies and actors like pirates
i. Pirate – hostis humani generis; enemy of all mankind
ii. Public enemy – a lawful enemy on whom a war has been declared by the
sovereign
d. Conduct of war (e.g. whether or not the enemy can be made a slave)
Roman Law:
o The foundation of all modern European and Western legal systems
The Law of Nations (Ius Gentium = roman universal law for all peoples)
o Was theoretically imagined as a body of rules constituted by natural reason
o Origins in Roman imperial practices
Law and the sea
o Maritime law and custom law developed across the Mediterranean during the
antiquity period
Medieval Natural Law and Just War
11th century – Roman law “rediscovered” in Europe
o Twin nexus of power: Roman Catholic Church and Holy Roman Empire;
competitors and supporters of each other
o Catholic Church and canon lawyers accepted the Holy Roman Emperor as
dominus mundi
, o But the popes also claimed to have universal authority – often clashed with Kings
and Emperors. Phillip IV clashed with Pope Bonafice VIII, who issued threats
after Philip taxed church assets
o However, Popes were also called to arbitrate legal disputes between rulers
The practice of Papal Arbitration was an important element of the law of
nations at the time
Sovereign Power
o In Medieval Europe, “universal” power was claimed both by the catholic church
and the Holy Roman Empire
o The rise of ius commune; a legal tradition founded upon Roman Law
o A gradual rise of sovereign kingdoms (France, England, Denmark, Poland, Spain,
etc)
Medieval Ius Gentium
o Natural law: classical Greek concept
o Ius gentium: roman law of nations
o Aristotelian philosophy: independent reason, human sociability↓
o Ius Gentium as man-made, universal, rational law; distinct from “static”
natural law
Just War Doctrine
o Starting point – Christian pacifism vs wars of religion. War might’ve been justified
in defence of Christian values
o St Thomas Aquinas’ criteria for Just War:
Public war (with sovereign authority)
Just cause (defence or fulfilment of rightful claims)
Rightful Intention (unselfish motivations)
o The idea of “just war” brings with itself certain ideas:
War as abnormal, peace as normal.
When a war is between a just cause and an unjust enemy, “neutrality”
becomes less defensible
Demand for collective action and sanctions
Struggles between Emperors, Popes and Kings led to a further development of ius
gentium: into Ius publicum Europaeum
War and Religion
Legal justifications for crusading
o Legal issue: non-Christians were accepted as sovereign under national law
o Collective self-defence (e.g. the sermon of Clermont story)
o Recovery of the Holy Land: Jerusalem as a universal exception
By natural law, Muslims held dominium de facto, but the Pope had
dominium de jure; Holy Places as Res Sancta
o Expansion of faith
Bringing pagans / savages to the flock; especially during the North-eastern
crusades
The idea of civilizing the savages as a iusta causa was accepted at a later
stage
Law of Nations (until 1870)
International Law (post 1870) – a branch of law in force between or above the sovereign
states of the world
Sources of intl. law (as per ICJ Statute Article 38(1)):
o International conventions (=treaties)
o International custom, as evidence of a general practice accepted as law
o General principles of law recognized by civilized nations (arbitration,
adjudication)
o Judicial decisions (such as those of the ICJ) and the teachings of the most highly
qualified publicists – only as subsidiary means
The law of treaties
o Treaties are the most important sources of intl. law
o Treaty – international agreement concluded between states in written form and
governed by international law (1969 Vienna Convention on the Law of Treaties)
o Might also be called conventions, charters, pacts, accords (still treaties)
The subjects of international law
1. Sovereign states
Criteria apply: population, territory, effective govt., capacity to enter intl.
relations, recognition by other states
2. Intergovernmental organizations
UN, WTO, ITU, ATS, etc.
3. Other entities (open to debate whether subject)
Political factions, individuals, corporations
Might be beneficiaries on behalf of the state, instead of subjects
Dispute resolution – a basic function of international law. There are various methods:
1. Direct negotiation, diplomatic settlements
2. Mediation
A third party assists and mediates →leads to an agreement
3. Arbitration
An arbitrator or arbitral tribunal decides →leads to an award
4. Adjudication
An established court or tribunal hears and decides →leads to a judgment
5. War (historically)
Areas within and beyond sovereign jurisdiction
o Land
Sovereign territory (within)
Antarctica (beyond)
o The Seas
Territorial sea, narrow 12-mile strip along the coast of the sea (within)
The high seas (beyond territorial jurisdiction, flag state jurisdiction applies)
Contiguous zones, Exclusive Economic Zone, continental shelf (limited
jurisdiction)
Deep seabed (beyond)
, o Airspace (within)
o Outer space (beyond)
Positive Law vs Natural Law
o Natural law: law which is “out there” to be “discovered”
Strength: noble, appealing, just (human rights, sustainability, dignity)
Weakness: subjectivity (who decides?), indeterminacy (what does it
mean?)
o Positive law: man-made, written law
Strength: formal legitimacy, visibility and precision of content
Weaknesses: politics (hard to agree on hard issues), indeterminacy (words
may be bent in many ways)
Rules vs Facts
o The basic model of legal argumentation:
Rule ˄ Fact → Conclusion
International law functions in absence of legislators, sovereign authority, police force,
department of justice or prosecutors. Why?
o No incentive to break intl. law, as the states themselves make it
o Bureaucratic inertia – a civil servant who routinely inspects compliance will not
suddenly stop doing so.
o Reciprocity – if country A mistreats country B’s citizens, it can expect country B
to do the same to its own citizens.
o Unlike people, states are few and attached to their territory. Nobody wants to be an
international pariah.
Sanctions in international law (in case of noncompliance)
o Retorsion – actions taken by one state to express dismay with another state’s
actions, such as recalling ambassadors, breaking off diplomatic relations
o Inadimplenti non est adimplendum: if A violates a treaty, B may do the same.
o Self defence and collective security actions, such as sanctioning particular
individuals.
International law in international relations theory:
o Self-proclaimed realists view intl. law as largely irrelevant, as they view states as
seeking only power and to further their own interests
o Liberal institutionalists think that intl. law can be relevant to create certainty in
trade and investments, reduce transaction costs and benefit all parties involved.
o Constructivists see intl. law as helping construct society – concluding alliances,
channelling political dialogue.
, Module 2 - Antiquity and Ius Gentium
There have always been elements of “the law of nations”. Modern international law has its
early roots in the Roman ius gentium.
Forms of international law in early antiquity:
1. Treaties (typically boundary, peace or alliance treaties)
a. Contain binding obligations
b. Oaths and curses (enforcement)
c. Assurances of good faith
2. Diplomatic practices
a. Diplomatic envoys and their inviolability
b. Access to ports or places
c. Treatment of foreigners (merchants or otherwise)
d. The practice of Arbitration can be found in antiquity
3. Law and war
a. The distinction between war and peace
b. Formalities of war, war as a legal procedure
c. A distinction between public enemies and actors like pirates
i. Pirate – hostis humani generis; enemy of all mankind
ii. Public enemy – a lawful enemy on whom a war has been declared by the
sovereign
d. Conduct of war (e.g. whether or not the enemy can be made a slave)
Roman Law:
o The foundation of all modern European and Western legal systems
The Law of Nations (Ius Gentium = roman universal law for all peoples)
o Was theoretically imagined as a body of rules constituted by natural reason
o Origins in Roman imperial practices
Law and the sea
o Maritime law and custom law developed across the Mediterranean during the
antiquity period
Medieval Natural Law and Just War
11th century – Roman law “rediscovered” in Europe
o Twin nexus of power: Roman Catholic Church and Holy Roman Empire;
competitors and supporters of each other
o Catholic Church and canon lawyers accepted the Holy Roman Emperor as
dominus mundi
, o But the popes also claimed to have universal authority – often clashed with Kings
and Emperors. Phillip IV clashed with Pope Bonafice VIII, who issued threats
after Philip taxed church assets
o However, Popes were also called to arbitrate legal disputes between rulers
The practice of Papal Arbitration was an important element of the law of
nations at the time
Sovereign Power
o In Medieval Europe, “universal” power was claimed both by the catholic church
and the Holy Roman Empire
o The rise of ius commune; a legal tradition founded upon Roman Law
o A gradual rise of sovereign kingdoms (France, England, Denmark, Poland, Spain,
etc)
Medieval Ius Gentium
o Natural law: classical Greek concept
o Ius gentium: roman law of nations
o Aristotelian philosophy: independent reason, human sociability↓
o Ius Gentium as man-made, universal, rational law; distinct from “static”
natural law
Just War Doctrine
o Starting point – Christian pacifism vs wars of religion. War might’ve been justified
in defence of Christian values
o St Thomas Aquinas’ criteria for Just War:
Public war (with sovereign authority)
Just cause (defence or fulfilment of rightful claims)
Rightful Intention (unselfish motivations)
o The idea of “just war” brings with itself certain ideas:
War as abnormal, peace as normal.
When a war is between a just cause and an unjust enemy, “neutrality”
becomes less defensible
Demand for collective action and sanctions
Struggles between Emperors, Popes and Kings led to a further development of ius
gentium: into Ius publicum Europaeum
War and Religion
Legal justifications for crusading
o Legal issue: non-Christians were accepted as sovereign under national law
o Collective self-defence (e.g. the sermon of Clermont story)
o Recovery of the Holy Land: Jerusalem as a universal exception
By natural law, Muslims held dominium de facto, but the Pope had
dominium de jure; Holy Places as Res Sancta
o Expansion of faith
Bringing pagans / savages to the flock; especially during the North-eastern
crusades
The idea of civilizing the savages as a iusta causa was accepted at a later
stage
