Realism | Edexcel A-Level Politics
Updated: Sep 29
For Specification 9PL0
Edexcel A-Level Politics | Free Revision Notes
Estimated study time:Â 50 minutes
Realism A-Level Politics revision focuses on one of the main perspectives used to understand global politics. You need to understand why realists treat sovereign states as the key actors, how the balance of power operates, what is meant by international anarchy, and why the security dilemma can contribute to conflict. These ideas build directly on state sovereignty [The state: nation-state and national sovereignty] and prepare you to study the contrasting arguments of liberalism [Liberalism]. Edexcel identifies all four as central elements of realism.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define realism, international anarchy and the security dilemma.
Explain why realists regard sovereign states as the key actors in global politics.
Explain the relationship between states, state sovereignty and the balance of power.
Analyse the implications of international anarchy for relations between states.
Explain how the security dilemma may increase tension and conflict.
Analyse why realists regard war as inevitable.
Revision Notes đź“š
Realism A-Level Politics revision: the core framework
Realism is a broad school of thought in international relations which views world politics as a continuing field of conflict between actors pursuing power.
The Edexcel specification identifies four central ideas of realism:
States as key actors, linked to state sovereignty and the balance of power.
International anarchy and its implications.
The inevitability of war.
The security dilemma.
These ideas are interconnected. Realism does not simply say that conflict happens. It provides a chain of reasoning explaining why competition and conflict remain persistent features of global politics.
Realist idea | Central argument | Connection to conflict |
States as key actors | Sovereign states remain central to global politics | States pursue and protect their own power and security |
Balance of power | Power is distributed between sovereign states | Changes in power can affect the security of other states |
International anarchy | There is no universal sovereign above states | States cannot depend on an overarching authority to guarantee their security |
Security dilemma | One state's attempt to become safer can make others feel less secure | Reciprocal responses increase tension |
Inevitability of war | Conflict remains an enduring feature of world politics | Anarchy, competing states and security pressures make lasting harmony difficult |
Understanding different forms of influence in hard and soft power [Hard and soft power] will later help you apply the realist emphasis on power more widely.
States as the key actors in global politics
Realism places the state at the centre of global politics.
States possess sovereignty, meaning that they exercise their own political authority rather than existing beneath a worldwide government. For realists, this makes relations between states particularly important.
The realist argument therefore begins with three linked ideas:
the world is divided into sovereign states
these states are key political actors
there is no higher global authority exercising sovereignty over all of them
The behaviour of states consequently matters enormously. Each state must consider its own position, power and security in relation to other states.
This makes realism a strongly state-centred theory. Although global politics contains organisations and other actors, the specification requires students to understand the realist emphasis on states as the key actors.
This connects closely to your later study of the changing significance of different states in great powers, superpowers and emerging powers [Great powers, superpowers and emerging powers].
Why sovereignty matters to realism
State sovereignty reinforces the realist view because sovereign states retain their own authority.
If states are sovereign, there is no political authority above them equivalent to a government governing citizens within a state. This helps explain why realists give so much importance to power and security.
A useful chain of reasoning is:
state sovereignty → independent states → no superior worldwide authority → states must consider their own security → competition and tension may develop
In an exam, simply stating that "realists believe states are important" is not enough. Explain why sovereignty makes the state so important within the realist understanding of world politics.
Realism and the balance of power
The specification connects the realist view of states directly to the balance of power.
The balance of power concerns how power is distributed between sovereign states. For realism, states do not operate in isolation. Their position depends partly on the power possessed by other states.
If the power of one state changes, this may affect how secure other states feel. States therefore pay attention not only to their own position but also to the capabilities and influence of other states.
This links realism to your study of polarity and world order [Polarity and world order], where the distribution of power between states is considered on a wider global scale.
The relationship between power and security
For realists, power and security are closely connected.
A state may seek greater power because this appears to strengthen its ability to protect its sovereignty and interests. However, what increases the security of one state may appear threatening to another.
This is crucial because it leads directly to the security dilemma.
The logic can be expressed as:
States are sovereign.
There is no higher authority guaranteeing their security.
States therefore pay close attention to their own power and the power of others.
Attempts to improve one state's position may affect the perceived security of other states.
Other states may respond.
Competition and tension can increase.
This does not mean that every change in the balance of power automatically causes war. The realist argument is that the nature of the state system creates persistent pressures towards competition and conflict.
International anarchy
International anarchy means that the world system is leaderless. There is no universal sovereign or worldwide government.
This is one of the most important definitions to learn precisely.
⚠️ Anarchy does not simply mean chaos.
In everyday language, "anarchy" may suggest disorder. In realism, international anarchy has a more specific meaning. It refers to the absence of an overarching political authority above sovereign states.
The existence of states therefore differs from political life within a state. Within a state, a government exercises authority. At the international level, there is no equivalent worldwide sovereign with supreme authority over every state.
Implications of international anarchy
International anarchy matters because states cannot assume that a higher authority will always protect them.
From a realist perspective, this creates uncertainty about the intentions and behaviour of other states.
The reasoning is:
international anarchy → absence of overarching authority → uncertainty between sovereign states → concern about security and power → greater potential for competition and conflict
This idea becomes particularly important when studying anarchical society and society of states [Anarchical society and society of states]. That later approach also begins from the absence of an overarching authority but considers whether states can nevertheless develop greater co-operation.
International anarchy and sovereignty
International anarchy and state sovereignty reinforce one another.
If states are sovereign, they do not recognise a universal political authority above themselves. If there is no worldwide sovereign, the international system remains anarchic.
Therefore:
State sovereignty | International anarchy |
States possess their own political authority | No universal sovereign possesses authority over all states |
Focuses on the independence and authority of individual states | Focuses on the structure of the international system |
Helps explain why states remain key actors | Helps explain why relations between states can be uncertain |
A strong answer should be able to connect these concepts rather than treating them as isolated definitions.
The security dilemma
The security dilemma is the theory that actions taken by one state to increase its security can cause other states to respond in similar ways, increasing tension and potentially producing conflict.
It is one of the clearest examples of how realist ideas connect together.
How the security dilemma develops
Imagine two sovereign states, State A and State B.
State A feels insecure.
Because there is no worldwide authority guaranteeing its safety, State A decides to strengthen its military capability.
State B observes State A's actions.
State B cannot be certain why State A is becoming stronger.
State B becomes less secure.
Measures intended to protect State A can therefore appear threatening to State B.
State B responds.
It strengthens its own security.
State A sees State B's response.
State A may now feel even more threatened.
Tension increases.
Both states may end up feeling less secure even though their original actions were intended to make them safer.
This is the central paradox of the security dilemma:
An attempt by one state to increase its own security may decrease the perceived security of another state.
The Edexcel glossary specifically defines the security dilemma in terms of one state's security measures prompting similar responses from others and producing increased tensions capable of creating conflict.
Why the security dilemma is realist
The security dilemma depends on several other realist assumptions:
sovereign states
↓
international anarchy
↓
no universal authority guaranteeing security
↓
states take action to protect themselves
↓
other states react to those actions
↓
tension increases
↓
conflict becomes more likely
This chain is extremely useful in examination answers because it converts several separate definitions into a developed piece of political analysis.
The 2020 examiner report praised stronger responses that went beyond naming the security dilemma and clearly explained how attempts to increase security could trigger responses by other states, instability, tension and eventually conflict.
Realism and the inevitability of war
The specification explicitly requires students to understand the realist idea of the inevitability of war.
Realism defines world politics as a continuing field of conflict among actors pursuing power. The argument that war is inevitable follows from the wider realist understanding of the international system.
Three ideas are particularly important.
1. States pursue power and protect their position
States are the key actors in global politics. They operate in relation to other sovereign states and must consider their own power and security.
Competition therefore cannot simply be removed from international politics.
2. International anarchy prevents guaranteed security
There is no worldwide sovereign capable of guaranteeing the security of every state.
States therefore exist within a system in which uncertainty remains. Even where states are not currently at war, there is no overarching authority capable of permanently eliminating competition between them.
3. The security dilemma can turn defensive behaviour into greater tension
The security dilemma explains why conflict does not require every state to begin with aggressive intentions.
A state may take action because it wants to become safer. Another state may interpret that action as threatening and respond. The first state can then react again.
Therefore, realist reasoning can be summarised as:
anarchy + sovereign states + pursuit of power/security + security dilemma → recurring tension and conflict → war remains inevitable
The important word is inevitable. In an examination question about the likelihood of war, you must keep returning to whether each realist argument explains why conflict cannot permanently be removed from the international system.
The 2025 examiner report identified this as a major discriminator. Weaker candidates sometimes described realism generally, while stronger responses remained focused specifically on the inevitability of war.
How the main realist ideas fit together
Realism becomes much easier to remember if you learn it as a connected argument rather than five separate definitions.
Stage | Realist reasoning |
1 | States are the key actors in global politics. |
2 | States possess sovereignty. |
3 | There is no universal sovereign above these states, creating international anarchy. |
4 | States therefore remain highly concerned with their power and security relative to others. |
5 | Changes in power or security can affect the balance between states. |
6 | Attempts by one state to increase its security may make another state feel threatened. |
7 | The resulting security dilemma can increase tension and conflict. |
8 | Realists therefore see war as an enduring and ultimately inevitable feature of global politics. |
For later revision, you will need to contrast this argument directly with realist and liberal views [Realism and liberalism compared].
Applying realism in an examination
Realism is part of the Comparative Theories section of Global Politics, but the specification expects realism and liberalism to be applied throughout the Global Politics course.
This means you need more than definitions.
For each realist concept, practise answering three questions:
What does the concept mean?
Why does realism make this argument?
What consequence does it have for power, security or conflict?
For example:
Weak explanation: Realists believe in international anarchy.
Developed explanation: Realists argue that international politics is anarchic because there is no universal sovereign above states. This means states cannot depend on an overarching authority to guarantee their security, helping to explain why competition and conflict remain persistent.
The second version contains both knowledge and a logical chain of reasoning.
Eventually, you will apply these ideas across other Global Politics topics in applying comparative theories to global politics since 2000Â [Applying comparative theories to global politics since 2000].
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 an ongoing field of conflict between actors pursuing power. | Use it to frame arguments about states, power, security, anarchy and conflict. |
State sovereignty | The authority possessed by a state, making sovereign states central actors in realist explanations of global politics. | Link sovereignty to the absence of a universal authority and the importance of states. |
Balance of power | The distribution of power between sovereign states and their positions relative to one another. | Use it when explaining why changes in one state's power may affect other states. |
International anarchy | A leaderless international system with no universal sovereign or worldwide government. | Use it to explain why states cannot rely on an overarching authority to guarantee their security. |
Security dilemma | A situation in which measures taken by one state to increase its security lead other states to respond, raising tensions and potentially creating conflict. | Use it as a developed explanation of why attempts to increase security can actually make conflict more likely. |
Hints from the Examiner Reports đź’ˇ
Examiner hint:Â Explain concepts through a chain of reasoning. In 2020, stronger answers did not merely define the security dilemma. They showed how one state's attempt to increase security could lead other states to respond, creating instability, increased tension and conflict.
Examiner hint: Keep your analysis tightly focused on the wording of the question. In 2025, the degree to which candidates focused specifically on the inevitability of war helped distinguish stronger from weaker responses. Simply describing realism was not enough.
Examiner hint:Â In the compulsory comparative-theories question, knowledge must underpin analysis. Strong responses connect concepts rather than presenting separate blocks of description.
Examiner hint:Â Remember the synoptic requirement when you move on to comparative questions. The examiner reports note that some otherwise strong answers could not reach the highest level because they did not make relevant connections to core political ideas.
Common Mistakes ⚠️
Mistake: Treating international anarchy as simple chaos
Why this is incorrect: International anarchy has a precise meaning in the specification. It means that the global system has no universal sovereign or worldwide government. It does not simply mean that world politics is completely chaotic.
How to improve: Always define anarchy through the phrase absence of an overarching authority before explaining its implications.
Mistake: Describing the security dilemma as deliberate aggression
Why this is incorrect: The security dilemma begins when a state takes action intended to increase its own security. The problem is that other states may respond to those actions, producing greater tension.
How to improve: Remember the sequence: security measure → reaction by another state → further insecurity → tension → possible conflict.
Mistake: Defining concepts without connecting them
Why this is incorrect: Realism is an interconnected argument. International anarchy helps explain security concerns, which help explain the security dilemma, which supports the argument about the inevitability of war.
How to improve: Use linking phrases such as "therefore", "this means that", "as a consequence" and "which makes conflict more likely".
Mistake: Writing that war is inevitable without explaining why
Why this is incorrect: "Inevitable" is not simply a fact to memorise. It is a conclusion reached from realist arguments about states, power, anarchy and security.
How to improve: Build a chain of reasoning ending with conflict: anarchy → insecurity → state responses → tension → conflict.
Mistake: Losing focus on the precise question
Why this is incorrect: The 2025 examiner report found that weaker answers sometimes described realism and liberalism generally instead of addressing the specific issue of the inevitability of war.
How to improve: Repeat the central concept from the question throughout your analysis. If the question is about war, every paragraph should explain what your point means for the likelihood or inevitability of conflict.
Exam-Style Questions ✍️
Questions
1. Define international anarchy. (1 mark)
2. State two main ideas associated with the realist view of global politics. (2 marks)
3. Explain one implication of international anarchy for sovereign states. (4 marks)
4. Explain the relationship between state sovereignty and the balance of power in realist thinking. (6 marks)
5. Consider the following scenario:
State A increases its military capability because its government believes this will make the country more secure. State B interprets the increase as a possible threat and responds by strengthening its own military capability. State A then becomes increasingly concerned about State B.
Using the scenario, analyse how the security dilemma can increase tension between states. (6 marks)
6. Analyse how international anarchy supports the realist argument that war is inevitable. (12 marks)
7. Analyse the relationship between state sovereignty, the balance of power and international anarchy in realism. (12 marks)
8. Analyse how the security dilemma supports the realist view that conflict remains an inevitable feature of global politics. (12 marks)
Answers and mark scheme
1. Define international anarchy. (1 mark)
Award 1 mark for:
the absence of a universal sovereign, worldwide government or overarching authority in the international system.
2. State two main ideas associated with the realist view of global politics. (2 marks)
Award 1 mark for each valid idea, up to 2 marks:
states are key actors
state sovereignty
balance of power
international anarchy
inevitability of war
security dilemma
3. Explain one implication of international anarchy for sovereign states. (4 marks)
A strong answer should explain a developed chain such as:
international anarchy means there is no overarching worldwide authority
therefore states cannot assume that a higher political authority will guarantee their security
sovereign states must consider their security in relation to other states
this can increase uncertainty, competition or the potential for conflict
Award marks according to the accuracy and development of the explanation.
4. Explain the relationship between state sovereignty and the balance of power in realist thinking. (6 marks)
Credit developed points including:
realists regard sovereign states as the key actors in global politics
states possess their own political authority
relations therefore take place between independent sovereign states
realists pay attention to the distribution of power between those states
the position or power of one state can affect the position and perceived security of others
this means state sovereignty and the balance of power are closely connected within the realist view of global politics
Higher marks require a connected explanation rather than separate definitions.
5. Analyse how the security dilemma can increase tension between states. (6 marks)
Credit:
State A's original action is intended to increase its security
State B interprets the action as potentially threatening
State B responds by increasing its own capability
State A now perceives State B as a greater threat
both states may therefore feel less secure despite taking measures designed to increase security
this reciprocal process raises tension and creates greater potential for conflict
A strong answer should apply the terminology security dilemma directly to the scenario.
6. Analyse how international anarchy supports the realist argument that war is inevitable. (12 marks)
Strong responses should develop several connected chains of reasoning. Relevant content includes:
international anarchy means no universal sovereign exists above states
sovereign states therefore remain responsible for considering their own security
uncertainty exists because there is no overarching authority capable of permanently guaranteeing security
states remain concerned with power and the behaviour of other states
changes in power may affect how secure other states feel
security measures can produce the security dilemma
reciprocal reactions can increase tension and conflict
these structural pressures help explain why realists see conflict and war as enduring features of global politics
For the highest level, knowledge should be carefully selected to support consistent analysis rather than presented as a list of definitions.
7. Analyse the relationship between state sovereignty, the balance of power and international anarchy in realism. (12 marks)
A strong response may develop three main relationships:
Sovereignty and anarchy:Â sovereign states retain their own authority, while no universal sovereign exists above them.
Sovereignty and balance of power:Â because states remain key actors, their relative power becomes important to their relationships with one another.
Balance of power and anarchy:Â without an overarching authority guaranteeing security, changes in the power of one state can affect the calculations and security concerns of others.
The strongest answers will connect all three concepts into a coherent realist explanation of global politics.
8. Analyse how the security dilemma supports the realist view that conflict remains an inevitable feature of global politics. (12 marks)
Credit developed analysis showing that:
international anarchy means there is no universal authority guaranteeing the security of states
states may therefore take measures designed to improve their own security
other states may regard these measures as threatening
they may respond with security measures of their own
the original state can then perceive the response as an additional threat
this creates a continuing cycle of insecurity and tension
importantly, conflict can emerge even when the initial action was intended defensively
the security dilemma therefore helps explain the realist conclusion that the international system continually creates conditions in which conflict can develop
A high-level response should remain focused throughout on why this supports the claim that war or conflict is inevitable, rather than merely describing the security dilemma.
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