International Relations Theories 101: Realism


International relations theories are one of the important parts of the international relations discipline. These theories seek to explain how the international system works. Using these theories international relations experts, diplomats, and governments aim to understand the motivations and goals behind the policy of an actor on the world stage. When theories fail to explain events and/or transformations, in other words, lose their validity in a specific situation, a new theory may emerge or an existing theory that is successful in explaining the situation in question may come to the fore. On the other hand, existing theories may be more successful in explaining actors' attitudes towards a specific situation.

The six theories that will be examined in this series are the most popular and key theories. Non-western theories that are generally left out in theory books will be examined in the sixth part of the series.

The International Relations Theories 101 series is therefore divided into six parts:

1. International Relations Theories 101: Realism & Neo-Realism

2. International Relations Theories 101: Liberalism & Neo-Liberalism

3. International Relations Theories 101: Constructivism - Social Constructivism

4. International Relations Theories 101: Marxism

5. International Relations Theories 101: Critical Theories

6. International Relations Theories 101: Non-Western Theories

Figure 1: Sovereign states are the only actors of international system
Figure 1: Actors of world politics

International Relations Theories 101: Realism & Neo-Realism

Realism is the oldest theory in international relations. The activities of actors in the international arena cannot be properly studied without being associated with realism. So much so that the origins of Realism go back even further than the 1648 Treaty of Westphalia, which is accepted as the beginning of international relations. The main arguments of Realism can be found in the thoughts of Thomas Hobbes, Thucydides, and Niccolò Machiavelli. For example, what Thucydides saw during his lifetime was the conflict between Greek city-states and between Greek and non-Greek empires (Jackson & Sørensen, 2013, p. 67). Thucydides realized the inequality of power between the warring states and concluded that it was inevitable and natural. Much like today, the international system during the Peloponnesian War was composed of strong and weak states as well as great powers. States with different capacities all had one goal: to survive. They could do so if they realized the rules of this unequal system and acted accordingly. (Jackson & Sørensen, 2013, p. 63).

Thucydides is not the only political philosopher to identify survival as a state's main goal. Machiavelli also defined the sole purpose of states as survival. States will fight for their existence and be cruel if their interests require it, but as a result, they will survive. States that cannot do so will either be in alliance with the great powers or accept extinction. The safest situation for the states will be when they defeat all their enemies and become an empire (Machiavelli, 2020). Failure to consolidate this empire opens the state to the possibility of war. Thomas Hobbes offers different reasons for the high possibility of war. He emphasizes conflicts of interest and human selfishness. As it's humans' intrinsic nature to always desire further resources, their interests will come into conflict at some point. Subsequently, war will be inevitable. Hobbes, who started his explanations with the definition of the state of nature, defines it as a permanent state of war (Jackson & Sørensen, 2013, p. 71). In the state of nature, there is no overarching authority to prevent the state of war. This scenario is the realists' definition of the international system: an anarchic system. Based on this, the key concepts of realism can be listed as follows: an anarchic international system, an unequal balance of power, and states as the only actors. Below is a closer look at how realists interpret these concepts.

Figure 2: Importance of military power in realism

Realists define the international system as anarchic. However, this definition does not refer to chaos. Realists mean there is no higher authority to rule or control the system. International politics take place among individual sovereign states (Dunne & Schmidt, 2014, p. 101). Thus, it is inevitable for independent states to consider themselves as a higher authority and will not accept any other authority above themselves. Also, as a feature of the anarchic international system, there is endless competition for power as well as limited resources between states. Inside a system where states compete with each other for power, they can only trust themselves. This is the essence of what realists call a self-help system and it is deemed necessary within an anarchic system (Dunne & Schmidt, 2014, p. 101). The self-help system stresses the point that other actors or international organizations are untrustworthy as well as holding states accountable for their own security (Dunne & Schmidt, 2014, p. 108). While assuring their security, states can create insecurity for other states (Dunne & Schmidt, 2014, p. 108); this is coined a security dilemma. The most known example of the security dilemma is the arms race. A state that increases its military power to ensure its security poses a threat to other states and this leads other states to increase their military power. Thus, states with high military capacity begin to perceive each other as a threat.

According to Realist understanding, states are the only actors in the international system. In Thucydides and Machiavelli’s eras, the political unit was city-states. After 1648, with the Treaty of Westphalia, today's sovereign states emerged and Realism accepted these sovereign states as the actors of the international system. This is called the state-centric assumption of realism or statism (Dunne & Schmidt, 2014, p. 101). After this date, states were accepted as the legitimate representatives of their territories and peoples, and can legitimately use power over the given territory. Consequently, sovereignty refers to states' supreme authority in their territorial space (Dunne & Schmidt, 2014, p. 107). According to this state-centric approach, non-state entities are not considered actors in the system.

Figure 3: Ingram Pinn's illustration shows the competition for limited resources
Figure 3: Ingram Pinn's illustration shows the competition for limited resources

It is paramount to repeat that the principal aim of states is survival. In an anarchic environment, states need the power to protect their existence because under such an environment survival of states cannot be guaranteed (Dunne & Schmidt, 2014, p. 101). World history is a testament that states can and have annihilated each other because of power inequality. For that reason, from the perspective of Realism, it is vital that states have as much power as possible. This power is defined as military power. The definition first referred to the numerical size of an army, it then evolved into the destructiveness of an army's weapons. Nonetheless, it has always been evaluated as a military power. For example, during the Cold War, for realists, power was equal to nuclear power. Both the United States and the Soviet Union perceived each other's nuclear power as a threat (Keyik & Erol, 2019, p. 39). While explaining the security dilemma, it was mentioned that states responded to threat perception by increasing their military forces. However, even the increase in the power of a small state against a superpower will not be enough to increase the security of the small state. Realism provides a solution to this situation with its power balance system. According to this system when a small state is threatened by a great power it should establish alliances or join a coalition of states to preserve its existence (Dunne & Schmidt, 2014, p. 101). This mechanism is vital in terms of preventing a dominant power from threatening all other states.

Figure 4: Bipolar system during the Cold War

The power struggle between states is a zero-sum game for Realists (Dunne & Schmidt, 2014, p. 107): when one wins the other loses. In such an environment, conflict will inevitably arise between states vying for the same resources. In the mentioned scenario, as there are no international moral principles, Realism advocates for states to do what is in their interest. Consequently, Realism does not accept the validity and competence of international law. In parallel, this theory does not believe that organizations such as the United Nations (UN) and the European Union (EU) will also be successful. The inability of the League of Nations to prevent the outbreak of the Second World War sets an example that supports the argument of Realism. Notwithstanding, during the Cold War period, Classical Realism could not explain why the two poles, the United States and the Soviet Union, didn’t attack each other. In the rapidly changing world stage, the emergence of neo-realism, by adding new concepts to the discussion, seeks to clarify the issues that Realism cannot answer.

It should be noted that there is no difference between neo-Realism and Realism in terms of basic concepts. Neo-Realism emerged to develop a more scientific and less historical approach to state behaviour (Joseph, 2014, p. 5). As a result, the most important difference between them was the introduction of a structure (p. 15) in neo-Realism. The structure was an abstract frame that was created by the states. After it was formed, it became a determinant in their political movements. In the beginning, it arose from the relations of states that had become tradition over the centuries. Therefore, a similarity can be drawn between structure and culture. People are born into a particular culture and live by its rules. The structure is exactly like that for states. Kenneth N. Waltz, considered one of the pioneers of Neo-Realism, defines the international system as a whole consisting of political structures and interacting elements (states). Neo-Realism explains the movements of states by structure (Kapitonenko, 2022, p. 32).

According to Waltz, international relations do not equate to merely actions undertaken by states. There are many social, cultural, ethnic, economic and religious factors that affect these relations. Let’s continue with our last example. Neo-Realism attributes the fact that there is no war between the poles in the Cold War, due to the necessity of the structure. According to Kenneth N. Waltz, the world system can be unipolar (only one state is a superpower), bipolar (two states are superpowers), and multipolar (more than two states are superpowers) according to the great powers it contains. According to him, the most stable system is the bipolar world system (Joseph, 2014, p. 6). The reason is the bipolar system is easier to balance and international relations are more predictable. Neorealism can be divided into offensive and defensive realism. With Waltz, the defensive approach argues that security is crucial and advocates for states to follow a defensive path that will preserve the status quo when a threat to security arises. The offensive approach, with the contribution of another important representative of the neo-realist theory, John Mearsheimer argues that the way to ensure security is to prioritize its power to become a hegemonic power.

Reflections of Realism in today’s world politics include the Cold War, the Six Day War (1967), and the United States' activities in Afghanistan and in Iraq. The Cold War is a great example of the arguments of Realism and Neo-Realism as it created two formal alliance systems: the Warsaw Pact and the North Atlantic Treaty Organization (NATO). Small states chose one of these two sides, aiming to protect themselves from the opposing side; this is an illustration of a balance of power. On the other hand, Neo-Realism explains the United States and the Soviet Union as not attacking each other due to the necessity of structure. In consequence, these two states did not enter into a hot conflict, they did not engage in an active armed conflict, with each other (Dunne & Schmidt, 2014, p. 107). In the case of the Six Day War in 1967 between Israel, Egypt, Jordan, and Syria, Israel displayed an example of the utilisation of power in accordance with Realism and Neo-Realism. At the beginning of the war, Israel had disadvantages in terms of the distribution of power. In other words, in terms of military power, Egypt, Jordan, and Syria were superior in numbers. However, Israel was successful at leveraging its military and economic power. Its victory proved that it is not quantity that matters in the modern international stage but capacity, just as realists argue (Dunne & Schmidt, 2014, p. 108). Finally, it is clear that the US's activities in Afghanistan and the US-led intervention in Iraq do not comply with the UN's non-intervention principle. (Dunne & Schmidt, 2014, p. 107). This intervention exhibits a scenario where there are no internationally valid principles, as Realism claims.

To sum up, states are the only actors in international politics. The aim of states is to survive. To survive, states must have high military power. If they cannot have this, they should establish alliances with other states. States should act by pursuing their interests as there are no internationally valid moral principles. The international system is anarchic and it is the fears, greed and selfishness of the states that determine this system. Neo-Realism emerged as a way to make realism more scientific. Its biggest difference from classical realism is that it claims that the structure determines the movements of states within the system. Neo-Realism is divided into two subtitles: offensive and defensive. While the defensive approach displays an approach that mantains the status quo, the offensive approach always suggests maximizing power. Realism, which has ancient roots, is still at the heart of international relations in the modern age.

Bibliographical References

Dunne, T. & Schmidt C. D. (2014). ‘Realism’, in Baylis, J., Smith, S. & Owens, P. (eds), The Globalization of World Politics, (6th ed., pp. 99-112). Oxford: Oxford University Press. Jackson, R & Sørensen, G 2013, ‘Realism’, Introduction to International Relations, (5th ed., pp. 65-98). Oxford University Press, Oxford. Joseph, J. (2014). Realism and neorealism in international relations theory. The Encyclopedia of political thought, 3142-3151. Kapitonenko, M. (2022). International Relations Theory (1st ed.). Routledge. Keyik, M., & Erol, M. S. (2019). REALİZME GÖRE GÜÇ VE GÜÇ DENGESİ KAVRAMLARI. Uluslararası Kriz ve Siyaset Araştırmaları Dergisi, 3(1), 12-49. Machiavelli, N. (2020). Hükümdar (20th ed.) Türkiye İş Bankası Kültür Yayınları.

Visual Sources


Pinn, I. (2016). How the west has lost the world. [Illustration]. Financial Times. Retrieved from


(2018) Global Balance of Power. [Illustration]. Saudi Gazette. Retrieved from


Pinn, I. (2014) How the best of times is making way for the worst. [Illustation]. Financial Times. Retrieved from


(2022) The Changing World Order. [Illustation]. Foreign Affairs. Retrieved from

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Yaprak Akkaya

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