Realism and Liberalism Compared | Edexcel A-Level Politics

For Specification 9PL0

Edexcel A-Level Politics | Free Revision Notes

Estimated study time: 55 minutes

exam questions by topic 👇

Realism and liberalism compared A-Level Politics revision brings together the two major perspectives in Edexcel Global Politics. You need to compare their contrasting assumptions about human nature and power, their explanations of order, security and conflict, and their views of states and international organisations. The key skill is direct comparison, not simply describing each theory separately. This lesson therefore builds on realist ideas [Realism] and liberal ideas [Liberalism], before preparing you to apply both perspectives to contemporary global politics. The specification identifies these three areas of division explicitly.

Learning Objectives 🎯

By the end of this revision page, you should be able to:

• Compare realist and liberal assumptions about human nature.

• Analyse how realism and liberalism understand the role of power in global politics.

• Compare realist and liberal explanations of international order and security.

• Explain why realism and liberalism reach different conclusions about the likelihood of conflict.

• Compare the significance each perspective gives to sovereign states.

• Analyse their contrasting expectations about the impact of international organisations.

Revision Notes 📚

Realism and liberalism compared A-Level Politics revision

Edexcel requires you to understand the divisions between realism and liberalism in relation to three specific areas:

1. human nature and power

2. order and security and the likelihood of conflict

3. the impact of international organisations and the significance of states 

This is therefore a lesson about comparison.

You should already understand the individual theories from realist arguments about states, anarchy and security [Realism] and liberal arguments about co-operation and interdependence [Liberalism]. Here, the focus changes from "What does realism say?" or "What does liberalism say?" to:

Exactly how and why do the two perspectives disagree?

At the broadest level, the distinction is this:

Realism	Liberalism
World politics remains a field of conflict among actors pursuing power	Power politics is not the sole outcome of international relations
Pessimistic implications for international relations	More optimistic possibilities for co-operation
States and sovereignty are central	Interdependence and international organisations can become increasingly significant
International anarchy creates insecurity	Harmony and balance are possible
Security dilemma can increase tensions	Complex interdependence can encourage co-operation
War is regarded as inevitable	War is not regarded as inevitable

The specification's glossary defines realism through continuing conflict and the pursuit of power, while liberalism emphasises mutual benefits and co-operation.

Human nature: pessimism versus optimism

The first required comparison concerns human nature.

The realist view of human nature

Realism has a pessimistic view of the implications of human nature for global politics.

The wider realist approach sees actors pursuing power and assumes that competition remains a persistent feature of world politics.

From this perspective, the behaviour of states reflects a world in which:

• interests can conflict

• actors pursue power

• competition remains important

• lasting harmony is difficult to achieve

This helps explain why realism reaches pessimistic conclusions about the likelihood of peace.

The liberal view of human nature

Liberalism is more optimistic.

The specification explicitly identifies liberal optimism about human nature and the significance of morality. Liberals therefore see greater potential for:

• rational behaviour

• moral decision-making

• recognition of common interests

• co-operation

• harmony and balance

This connects to the Core Political Idea of liberalism, where rationalism describes humans as capable of reason and logic and able to make moral choices.

Direct comparison

Realism	Liberalism
More pessimistic about human behaviour	More optimistic about human behaviour
Emphasises competing interests and the pursuit of power	Emphasises reason, morality and possibilities for co-operation
Human behaviour contributes to persistent conflict	Human behaviour does not make conflict unavoidable
Helps support the belief that war is inevitable	Helps support the possibility of harmony and balance

The important analytical link is:

different assumptions about human nature → different expectations about relations between states → different conclusions about peace and conflict

The 2022 mark scheme confirms that this contrast was central to a question specifically asking candidates to analyse realist and liberal differences over human nature and power.

Human nature and the likelihood of conflict

Do not leave the human-nature comparison as an isolated definition.

Its importance lies in the consequences each perspective draws from it.

For realism:

pessimistic assumptions → competition and pursuit of power → continuing tensions → conflict remains unavoidable

For liberalism:

optimistic assumptions → reason and morality → recognition of shared interests → potential co-operation → peace and harmony become possible

This is a good example of AO2 analysis because you are explaining the significance of the difference.

The 2019 examiner report found that stronger candidates moved from the basic difference over the inevitability of war into analysis involving human nature, international anarchy, the security dilemma and complex interdependence.

Power: competition versus co-operation

The second part of this comparison concerns power.

Power is central to realism. The specification defines realism as a school of thought which believes world politics will remain a field of conflict among actors pursuing power.

Realist view of power

Realists place great importance on:

• states as key actors

• sovereignty

• the balance of power

• the relationship between power and security

• competition between political actors

A state's position cannot be considered independently of other states. If the power of one state increases, the position and security calculations of other states may be affected.

This connects directly to different forms of state influence [Hard and soft power] and to the wider distribution of power covered in world order [Polarity and world order].

Liberal view of power

Liberalism does not claim that power disappears.

Instead, the specification defines liberalism as rejecting power politics as the sole outcome of international relations.

This distinction matters.

Liberals argue that relations between political actors may also be characterised by:

• mutual benefits

• co-operation

• shared interests

• interdependence

• negotiation

• international organisations

Therefore, realism gives power competition a much more fundamental position in global politics, whereas liberalism believes that political relationships can develop beyond continuous competition for power.

Power and the balance of power

Realism links state power to the balance of power.

The realist international system consists of sovereign states whose power exists in relation to the power of others. This creates continuing concern with relative positions and security.

Liberalism instead emphasises the possibility of harmony and balance.

Be careful here, because these are not the same thing.

Balance of power in realism	Harmony and balance in liberalism
Concerns the distribution of power between sovereign states	Concerns the possibility of more peaceful and co-operative relations
States remain concerned about one another's power	States can identify shared interests
Competition remains central	Co-operation can become significant
Changes in power may generate insecurity	Interdependence can encourage greater stability

⚠️ Do not use "balance of power" and "harmony and balance" as interchangeable terms. They belong to different theoretical arguments in the specification.

Order: international anarchy versus co-operation

Realism and liberalism also disagree about how international order can be understood.

Realism and international order

For realists, the international system is characterised by international anarchy.

International anarchy means:

a leaderless world system with no universal sovereign or worldwide government.

States remain sovereign and there is no overarching political authority comparable with government inside a state.

The realist chain is:

sovereign states → no overarching authority → international anarchy → uncertainty and competition → continuing concern about security

Order is therefore fragile because states exist in a system where their security cannot be permanently guaranteed by a higher political authority.

Liberalism and international order

Liberals see greater possibilities for order through:

• harmony and balance

• complex interdependence

• global governance

• international organisations

Complex interdependence means that states and their fortunes are inextricably tied together. Global governance involves political integration among transnational actors aimed at negotiating responses to problems affecting more than one state or region.

The liberal chain is therefore different:

interconnected states → shared interests and problems → incentives to co-operate → international organisations and global governance → greater possibilities for order

Comparing the foundations of international order

Question	Realist answer	Liberal answer
What is the basic international environment?	Anarchic, with no overarching authority	Increasingly interconnected
What is central to order?	Sovereign states and the balance of power	Co-operation, interdependence and governance
Can political actors establish lasting co-operation?	Limited by the realities of state sovereignty and competition	Yes, shared interests can encourage continuing co-operation
How significant are international rules and institutions?	Less significant than sovereign states	Potentially important in promoting co-operation
Is harmony possible?	Limited and insecure	Yes, harmony and balance are possible

This debate prepares you for anarchy alongside rules and co-operation [Anarchical society and society of states], which examines whether states can form a society despite the anarchic nature of the international system.

Security: the security dilemma versus complex interdependence

One of the clearest contrasts between realism and liberalism is between the realist security dilemma and liberal complex interdependence.

Realism and the security dilemma

The security dilemma occurs when actions intended by one state to improve its security cause other states to respond with similar measures, increasing tensions that may create conflict.

For example, the logic is:

1. State A takes steps to increase its security.

2. State B perceives this as potentially threatening.

3. State B takes its own security measures.

4. State A becomes more concerned.

5. Tensions increase.

6. Conflict becomes more likely.

The crucial realist insight is that even an attempt to become more secure can create greater insecurity.

Liberalism and complex interdependence

Complex interdependence leads liberals towards almost the opposite conclusion.

If states and their fortunes are tied together:

1. the behaviour of one state affects others

2. states may develop shared interests

3. co-operation can provide mutual benefits

4. conflict may damage interconnected relationships

5. the incentive to resolve disputes peacefully can increase

The 2020 examination specifically required candidates to analyse differences between the realist security dilemma and liberal complex interdependence. The official mark scheme contrasted the instability generated by reciprocal security responses with the greater likelihood of co-operation arising from interconnectedness.

Security dilemma versus complex interdependence

Security dilemma	Complex interdependence
Associated with realism	Associated with liberalism
Starts from insecurity between sovereign states	Starts from states being closely interconnected
Security measures can create suspicion	Connections can create shared interests
State responses may escalate tension	Co-operation can become increasingly beneficial
Makes conflict more likely	Can make conflict less likely
Supports realist pessimism	Supports liberal optimism

This is an excellent comparison to learn because it links security, order and conflict in one argument.

Conflict: inevitable or avoidable?

This is perhaps the clearest division between the theories.

Realist position

The specification explicitly identifies the inevitability of war as a main realist idea.

Several realist arguments support this conclusion:

• world politics involves actors pursuing power

• states remain sovereign

• the system is anarchic

• there is no universal authority guaranteeing security

• security measures can generate the security dilemma

Together:

power competition + international anarchy + insecurity + security dilemma → war remains inevitable

Liberal position

Liberals do not argue that war cannot occur.

Instead, they reject the realist conclusion that it is inevitable.

Their reasoning is based on:

• optimism about human nature

• morality

• harmony and balance

• complex interdependence

• global governance

• international organisations

Together:

reason and morality + shared interests + interdependence + institutions → greater possibilities for co-operation → conflict is not inevitable

The distinction is therefore:

Realism sees war as an enduring and inevitable feature of global politics, while liberalism sees conditions under which co-operation can reduce its likelihood.

Why this comparison matters in an exam

A weak response might say:

Realists believe war is inevitable. Liberals believe peace is possible.

That demonstrates knowledge but very little analysis.

A stronger response explains the reason for the difference:

Realists regard international politics as anarchic, meaning there is no universal sovereign able to guarantee states' security. States therefore take responsibility for their own security, potentially generating a security dilemma. Liberals instead emphasise complex interdependence, through which states' fortunes become linked and co-operation can become mutually beneficial. The theories therefore reach different conclusions about whether conflict is inevitable.

The 2025 examiner report found that focus was a major discriminator in a question on the inevitability of war. Weaker candidates often described realism and liberalism separately, while stronger candidates kept returning to the precise comparison being asked.

States: central actors or increasingly constrained?

The third specification division concerns the significance of states.

Realist view of states

Realism explicitly identifies states as key actors in global politics.

Their significance is closely connected to:

• sovereignty

• the balance of power

• international anarchy

States possess their own political authority and exist without a universal sovereign above them.

For realism, this makes the sovereign state fundamental to understanding world politics.

This draws directly on sovereignty and the nation-state [The state: nation-state and national sovereignty].

Liberal view of states

Liberals do not argue that states simply disappear.

However, liberalism places much greater emphasis on:

• complex interdependence

• global governance

• international organisations

• growing patterns of co-operation

The liberal position therefore allows for a world in which sovereign states continue to exist but are increasingly connected to other actors and institutions.

This produces a fundamental disagreement:

Realism	Liberalism
States are the key actors	States remain important but operate within growing interdependence
Sovereignty is fundamental	Interconnectedness can constrain completely independent state action
State power remains central	Co-operation and institutions can have significant impact
International politics remains state-centred	Global politics cannot be explained by states alone

International organisations

The two perspectives also divide sharply over the impact of international organisations.

Realist perspective

Because realists see sovereign states as the key actors, they are comparatively sceptical about the independent significance of international organisations.

From the realist perspective:

• states remain sovereign

• states continue to pursue power and security

• anarchy remains a fundamental characteristic of the system

• organisations cannot remove the underlying competition between states

International organisations therefore do not overturn the realist state-centred interpretation of global politics.

Liberal perspective

Liberals are much more optimistic about international organisations.

The specification specifically includes the impact and growth of international organisations within liberalism.

International organisations fit liberal theory because they can:

• provide structures for negotiation

• facilitate co-operation

• help actors address shared problems

• contribute to global governance

• reflect complex interdependence

Their growth therefore supports the liberal argument that relations between states need not be determined solely by power competition.

You can later apply this debate directly to international political governance [The United Nations].

States and organisations: the fundamental disagreement

The clearest way to learn this section is as a disagreement about where political significance lies.

Realist reasoning:

sovereign states → key actors → power and security remain central → international organisations cannot eliminate state competition

Liberal reasoning:

interdependence → shared problems and interests → need for co-operation → international organisations grow → global governance becomes more significant

The 2021 examination asked directly about the impact of international organisations and the significance of states. The examiner report said a key differentiator was whether candidates addressed both elements, rather than discussing only states or only organisations.

Complete comparison of realism and liberalism

Area	Realism	Liberalism	Why the difference matters
Human nature	Pessimistic implications	Optimistic, with emphasis on morality and rationality	Shapes expectations about whether co-operation can endure
Power	Power pursuit is central to global politics	Power politics is not the sole outcome	Liberals see greater potential for mutually beneficial relationships
States	States are key actors	States remain important but operate in an interconnected system	The theories disagree over how state-centred global politics is
Sovereignty	Fundamental to the international system	Coexists with increasing interdependence and governance	Shapes different views of international authority
Order	Exists within an anarchic system	Harmony and balance can develop through co-operation	Liberals are more optimistic about stable international relations
Security	Security dilemma can increase insecurity	Interdependence can give states reasons to co-operate	The same search for security leads to contrasting theoretical expectations
Conflict	War is inevitable	War is not inevitable	This is one of the clearest divisions between the perspectives
International organisations	Limited by the continuing significance of sovereign states	Can have an important and growing impact	Liberals place greater faith in organised international co-operation
Global governance	Cannot remove the underlying realities of state power and anarchy	Likely to develop as actors address shared problems	The theories disagree over the capacity for collective management of global issues

The comparison as three chains of reasoning

For revision, it helps to reduce specification section 6.3 to three paired arguments.

Human nature and power

Realism: pessimistic assumptions → pursuit of power → competition

Liberalism: optimistic assumptions → rational and moral behaviour → co-operation

Order, security and conflict

Realism: international anarchy → insecurity → security dilemma → conflict → war inevitable

Liberalism: complex interdependence → shared interests → co-operation → harmony and balance → war not inevitable

States and international organisations

Realism: state sovereignty → states remain key actors → international organisations cannot remove state competition

Liberalism: interdependence → need for co-operation → international organisations and global governance grow in significance

If you can explain these three paired chains accurately, you have covered the core specification content for this lesson.

Preparing to apply the theories

This lesson compares the theories themselves. The next stage is to ask which theory better explains actual developments.

That is the focus of applying the theories to contemporary politics [Applying comparative theories to global politics since 2000].

Edexcel requires students to evaluate the extent to which realism and liberalism explain developments since 2000 across the other Global Politics content areas.

Before doing that, you should be able to ask of any issue:

• Would realism emphasise sovereign states, power, anarchy or security?

• Would liberalism emphasise interdependence, co-operation, governance or institutions?

• Which perspective provides the stronger explanation?

• What evidence would distinguish between the two?

That turns theory into usable examination analysis.

Key Words 🔑

Key word	Student-friendly definition	How it may be used in an exam
Realism	A school of thought which sees world politics as continuing conflict among actors pursuing power.	Use it when explaining state-centred politics, anarchy, security and inevitable conflict.
Liberalism	A school of thought which rejects power politics as the only outcome of international relations and emphasises mutual benefits and co-operation.	Use it to explain interdependence, harmony, governance and international organisations.
International anarchy	A leaderless international system with no universal sovereign or worldwide government.	Contrast it with liberal expectations about co-operation, governance and international organisations.
Security dilemma	A situation where one state's attempts to increase security lead others to respond, increasing tension and potentially causing conflict.	Contrast it with complex interdependence when analysing security and conflict.
Complex interdependence	The theory that states and their fortunes are inextricably tied together.	Use it to explain why liberals expect greater co-operation and a lower likelihood of conflict.

Hints from the Examiner Reports 💡

Examiner hint: Compare the theories directly. In 2025, weaker responses often described realism and then liberalism separately. Stronger answers remained focused on the exact division in the question and developed direct comparison.

Examiner hint: Move beyond basic identification of differences. The 2019 report noted that once candidates had established the disagreement over the inevitability of war, stronger responses analysed human nature, anarchy and the security dilemma against complex interdependence.

Examiner hint: Cover every element of a multi-part question. In 2021, a key differentiator was whether candidates dealt with both the significance of states and the impact of international organisations, rather than concentrating on only one.

Examiner hint: Build AO2 from AO1. A comparison should explain the consequence of a difference, for example, "because realism sees the system as anarchic, states cannot depend on a higher authority for security, whereas liberal interdependence creates incentives for co-operation."

Examiner hint: Do not forget synopticity in the compulsory comparative-theories question. Examiner feedback repeatedly notes that candidates can be prevented from reaching the highest level if they do not make relevant connections with Core Political Ideas.

Common Mistakes ⚠️

Mistake: Writing two separate mini-essays

Why this is incorrect: A paragraph describing realism followed by a paragraph describing liberalism does not automatically produce comparative analysis.

How to improve: Organise paragraphs around the point of disagreement, such as human nature, rather than around the name of the theory. Use phrases such as "whereas", "in contrast" and "this difference means that".

Mistake: Saying liberals believe power is irrelevant

Why this is incorrect: The specification defines liberalism as rejecting power politics as the sole outcome of international relations. It does not say that power has no importance.

How to improve: Say that liberals give greater significance to co-operation, mutual benefits, interdependence and institutions alongside power.

Mistake: Confusing international anarchy with chaos

Why this is incorrect: International anarchy specifically means that no universal sovereign or worldwide government exists.

How to improve: Define the term precisely first, then analyse how the absence of overarching authority affects security.

Mistake: Treating the security dilemma and complex interdependence as unrelated definitions

Why this is incorrect: They provide contrasting explanations of international security.

How to improve: Compare their consequences directly: the security dilemma can produce escalating insecurity, while complex interdependence can produce stronger incentives for co-operation.

Mistake: Claiming liberals believe war is impossible

Why this is incorrect: Liberalism argues that harmony and balance are possible and that war is not inevitable. This does not mean conflict cannot happen.

How to improve: Use precise language such as "less likely", "not inevitable" or "greater possibilities for peaceful co-operation".

Mistake: Ignoring one half of a question about states and organisations

Why this is incorrect: Examiner feedback from 2021 specifically identified coverage of both elements as a discriminator.

How to improve: Underline the separate demands before writing. If the question mentions both states and international organisations, make sure both appear throughout the comparison.

Exam-Style Questions ✍️

Questions

1. State one difference between realist and liberal views of human nature. (1 mark)

2. Define complex interdependence. (1 mark)

3. Explain one difference between realist and liberal views of power. (4 marks)

4. Explain why the security dilemma and complex interdependence lead to different expectations about international security. (6 marks)

5. Consider the following scenario:

Several sovereign states face a shared international problem. Some governments increase their individual security capabilities because they do not trust other states. At the same time, the states maintain negotiations through an international organisation because the problem affects them all.

Using the scenario, analyse how realism and liberalism would interpret the behaviour of the states differently. (6 marks)

6. Analyse the differences between realist and liberal views of human nature and power. In your answer you must discuss any relevant core political ideas. (12 marks)

7. Analyse the differences between realist and liberal approaches to order, security and the likelihood of conflict. In your answer you must discuss any relevant core political ideas. (12 marks)

8. Analyse the divisions between realism and liberalism over the significance of states and the impact of international organisations. In your answer you must discuss any relevant core political ideas. (12 marks)

Answers and mark scheme

1. State one difference between realist and liberal views of human nature. (1 mark)

Award 1 mark for identifying that:

• realism is more pessimistic about human nature, whereas liberalism is more optimistic.

2. Define complex interdependence. (1 mark)

Award 1 mark for:

• the theory that states and their fortunes are inextricably tied together.

3. Explain one difference between realist and liberal views of power. (4 marks)

A strong response should explain that:

• realism regards the pursuit of power as a fundamental feature of world politics

• the balance of power between sovereign states therefore has major significance

• liberalism rejects the idea that power politics is the sole outcome of international relations

• liberals instead see possibilities for mutually beneficial co-operation

Higher marks require the consequence of the difference to be explained rather than merely stated.

4. Explain why the security dilemma and complex interdependence lead to different expectations about international security. (6 marks)

Credit developed points including:

• the security dilemma is associated with realism

• actions by one state designed to improve security can prompt similar responses from other states

• this may increase tension and ultimately create conflict

• complex interdependence is associated with liberalism

• states and their fortunes are tied together

• interconnected states may therefore have greater reasons to co-operate, making conflict less likely

The strongest answers will make the contrast explicit throughout.

5. Analyse how realism and liberalism would interpret the behaviour of the states differently. (6 marks)

Credit analysis such as:

• realists would emphasise the sovereign states' distrust and their decision to improve their own security

• this reflects international anarchy because no overarching authority guarantees their security

• reciprocal security measures could produce a security dilemma

• liberals would emphasise the shared problem and continuing negotiation

• this reflects complex interdependence because the states' interests are connected

• the use of an international organisation supports liberal expectations about co-operation and global governance

6. Analyse the differences between realist and liberal views of human nature and power. In your answer you must discuss any relevant core political ideas. (12 marks)

A strong response should develop direct comparisons including:

Human nature

• realism has pessimistic implications for human behaviour in global politics

• liberalism is more optimistic and gives significance to morality and rational decision-making

• this produces contrasting expectations about whether lasting co-operation is possible

Power

• realism views world politics as a continuing field of conflict among actors pursuing power

• states and the balance of power are therefore central

• liberalism rejects power politics as the sole outcome

• it emphasises mutual benefits and co-operation

• these different attitudes to power contribute to realist pessimism and liberal optimism about international relations

Synoptic connection

• relevant Core Political Ideas can be used to develop the contrast, provided they remain focused on the question

For the highest level, knowledge should underpin consistent comparative analysis, rather than producing separate descriptions of the theories.

7. Analyse the differences between realist and liberal approaches to order, security and the likelihood of conflict. In your answer you must discuss any relevant core political ideas. (12 marks)

Credit developed comparative analysis including:

Order

• realism emphasises an international system without an overarching authority

• liberalism sees possibilities for harmony, balance, governance and organised co-operation

Security

• realism uses the security dilemma to explain how attempts to become safer may increase insecurity

• liberalism uses complex interdependence to explain why linked states may develop stronger incentives to co-operate

Conflict

• realism regards war as inevitable

• liberalism does not regard war as inevitable because morality, shared interests, interdependence and institutions create possibilities for co-operation

The strongest response will show how these three differences are connected rather than treating them as separate definitions.

8. Analyse the divisions between realism and liberalism over the significance of states and the impact of international organisations. In your answer you must discuss any relevant core political ideas. (12 marks)

A strong answer should address both parts directly.

Significance of states

• realism identifies states as key actors

• sovereignty and the balance of power reinforce their centrality

• liberalism recognises states but places them in a more interconnected political environment

International organisations

• realism remains sceptical about whether organisations can overcome state sovereignty, competition and international anarchy

• liberalism gives international organisations greater significance because they can facilitate negotiation and co-operation

• their impact and growth support liberal expectations about global governance

Overall comparison

• realism remains predominantly state-centred

• liberalism gives greater importance to relationships and institutions extending beyond independent state action

For the highest level, make comparisons continuously and include a relevant synoptic connection to Core Political Ideas.

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