C O M P A R A T I V E T H E O R IE S S T U D Y G U I D E
Realism and Liberalism are the two fundamental theories in international relations.
Realists see the world as a Westphalian state system, this is linked to conservatism via pragmatism
Liberals tend to see states as fundamentally interlinked due to complex interdependence, and view
non-state actors as significant too
CLASSICAL REALISM
Classical realist thinkers
• Thucydides – The History of the Peloponnesian Wars – 500BCE
• Niccolò Machiavelli – The Prince – 1513
• Thomas Hobbes – Leviathan – 1651
• Hans Morgenthau – Politics Among Nations – 1954
T HU C Y D I D E S – 5 0 0 B C E
States are only motivated by three things: fear, honour and self-interest
The ‘Thucydides Trap’: These motivations of fear, honour and self-interest can lead to war even if
nobody wants it and it would disadvantage all.
N I C C O L O M A C HI A VE L L I – 1 5 1 3
Machiavelli argued that a ruler finds most security in being feared rather than loved. He said that
men “being scoundrels, may break” the bond of love, but fear is “supported by the dread of pain
which is ever present.”
Thus, he suggests that if a ruler wants to maintain power, he should do whatever it takes to make his
subjects fear him. In the context of realism, this could mean that each state should act in radical self-
interest, putting itself first at all costs even if this means breaking down relations with other states.
HO B B E S – 1 6 5 1
Hobbes said that the state of nature was nasty, brutish and short. Human beings are full of fear and
selfishness. If we existed in the state of nature, every man would fight one another - a constant and
violent condition of competition in which each individual has a natural right to everything, regardless
of the interests of others.
HA N S M O R G E NT HA U – 1 9 5 4
States have no moral obligation to care about other states in the international system. ‘The struggle
for power is universal in time and space’
, KEY BELIEFS
1. People are selfish, competitive and vain. This behaviour is mirrored by states.
- Hobbes, Morgenthau
2. International relations is all about states
- focus on Westphalian model
- States are sovereign so are the only actors that count – IGOs and other non-state actors are
just a distraction
- states are unitary actors and are viewed from the outside. Not interested in the competing
interests within a state/location of sovereignty, regime, culture etc.
3. International relations is all about power
- it is always in a state’s interest to maximise power and this is all that counts
- ‘the strong do what they can and the weak suffer what they must’
4. Power is a zero-sum game – you win, or you lose. There is no win-win.
5. States are rational. They cannot trust each other, and they could lose everything so
therefore they must constantly aim to win
-Cruelty is more reliable than benevolence in maintaining power
6. States have no moral responsibility other than to act in their own national interest
- Who will look after their citizens other than the state. Belief in the ‘self-help’ nature of the
anarchic international state system
7. Conflict between states is likely, cooperation is not.
- States cannot trust each other and thus must compete, this competition prevents co-
operation and can spill over into war.
CLASSICAL LIBERALISM
Classical liberal thinkers
• Locke – Rationality, freedom, equality
• Rousseau – social contract, the general will. Developed the idea that all nations had the right to
self-determination
o The Stag Hunt Dilemma:
o Rousseau argued that in a theoretical quest for survival, two hunters would rather
co-operate and catch a stag, than hunt on their own and risk food insecurity – this
shows that because humans are rational, they will co-operate for a better outcome
for all.
• Kant – perpetual peace. Idea that republican constitutions and international trade enables co-
operation between states and all three together create peace. Practical measures to
incentivise states to co-exist peacefully
o Republican constitutionalism – republics are less likely to wage war against one
another as leaders are held accountable by their citizens
o The rule of law extended to cover relations between states
o Trade is instrumental to peace – states will have a selfish stake in the wellbeing of
one another if they share an economic system.
• David Ricardo – comparative advantage
o states should specialise in what they are good – e.g., Kenya and mangoes, India and
tea, Saudi Arabia and oil. This, alongside free trade, will create prosperous and
satiated economies.
• Woodrow Wilson – Nations’ right to self-determination. Internationalism.
2
Realism and Liberalism are the two fundamental theories in international relations.
Realists see the world as a Westphalian state system, this is linked to conservatism via pragmatism
Liberals tend to see states as fundamentally interlinked due to complex interdependence, and view
non-state actors as significant too
CLASSICAL REALISM
Classical realist thinkers
• Thucydides – The History of the Peloponnesian Wars – 500BCE
• Niccolò Machiavelli – The Prince – 1513
• Thomas Hobbes – Leviathan – 1651
• Hans Morgenthau – Politics Among Nations – 1954
T HU C Y D I D E S – 5 0 0 B C E
States are only motivated by three things: fear, honour and self-interest
The ‘Thucydides Trap’: These motivations of fear, honour and self-interest can lead to war even if
nobody wants it and it would disadvantage all.
N I C C O L O M A C HI A VE L L I – 1 5 1 3
Machiavelli argued that a ruler finds most security in being feared rather than loved. He said that
men “being scoundrels, may break” the bond of love, but fear is “supported by the dread of pain
which is ever present.”
Thus, he suggests that if a ruler wants to maintain power, he should do whatever it takes to make his
subjects fear him. In the context of realism, this could mean that each state should act in radical self-
interest, putting itself first at all costs even if this means breaking down relations with other states.
HO B B E S – 1 6 5 1
Hobbes said that the state of nature was nasty, brutish and short. Human beings are full of fear and
selfishness. If we existed in the state of nature, every man would fight one another - a constant and
violent condition of competition in which each individual has a natural right to everything, regardless
of the interests of others.
HA N S M O R G E NT HA U – 1 9 5 4
States have no moral obligation to care about other states in the international system. ‘The struggle
for power is universal in time and space’
, KEY BELIEFS
1. People are selfish, competitive and vain. This behaviour is mirrored by states.
- Hobbes, Morgenthau
2. International relations is all about states
- focus on Westphalian model
- States are sovereign so are the only actors that count – IGOs and other non-state actors are
just a distraction
- states are unitary actors and are viewed from the outside. Not interested in the competing
interests within a state/location of sovereignty, regime, culture etc.
3. International relations is all about power
- it is always in a state’s interest to maximise power and this is all that counts
- ‘the strong do what they can and the weak suffer what they must’
4. Power is a zero-sum game – you win, or you lose. There is no win-win.
5. States are rational. They cannot trust each other, and they could lose everything so
therefore they must constantly aim to win
-Cruelty is more reliable than benevolence in maintaining power
6. States have no moral responsibility other than to act in their own national interest
- Who will look after their citizens other than the state. Belief in the ‘self-help’ nature of the
anarchic international state system
7. Conflict between states is likely, cooperation is not.
- States cannot trust each other and thus must compete, this competition prevents co-
operation and can spill over into war.
CLASSICAL LIBERALISM
Classical liberal thinkers
• Locke – Rationality, freedom, equality
• Rousseau – social contract, the general will. Developed the idea that all nations had the right to
self-determination
o The Stag Hunt Dilemma:
o Rousseau argued that in a theoretical quest for survival, two hunters would rather
co-operate and catch a stag, than hunt on their own and risk food insecurity – this
shows that because humans are rational, they will co-operate for a better outcome
for all.
• Kant – perpetual peace. Idea that republican constitutions and international trade enables co-
operation between states and all three together create peace. Practical measures to
incentivise states to co-exist peacefully
o Republican constitutionalism – republics are less likely to wage war against one
another as leaders are held accountable by their citizens
o The rule of law extended to cover relations between states
o Trade is instrumental to peace – states will have a selfish stake in the wellbeing of
one another if they share an economic system.
• David Ricardo – comparative advantage
o states should specialise in what they are good – e.g., Kenya and mangoes, India and
tea, Saudi Arabia and oil. This, alongside free trade, will create prosperous and
satiated economies.
• Woodrow Wilson – Nations’ right to self-determination. Internationalism.
2
