The Three Perspectives on War: Liberal, Realist, and Identity Theory

1. Introduction

The reasons behind why wars happen has been a matter of debate for many years. Academics and policymakers have put forward different explanations, based on various schools of thought. In this essay, three such perspectives will be explored: the liberal perspective, the realist perspective, and the identity theorists' perspective. Each has its own strengths and weaknesses, but together they provide a more comprehensive understanding of why wars occur.

2. The liberal perspective

2.1 Rejecting the realist view of war

The liberal perspective on war is based on the idea that war is not an inevitable part of international relations, as realism would suggest. Rather, it is caused by specific circumstances that can be changed. This view was first put forward by Immanuel Kant in his essay "Perpetual Peace: A Philosophical Sketch" (1795). Kant argued that war is not natural or inevitable, but is caused by specific "unsocial" tendencies within societies. These include competition, egoism, and the love of glory. If these unsocial tendencies can be removed, then war would no longer occur.

2. 2 The importance of democracy in avoiding war

One of the key ideas in liberalism is that democracy is a key factor in preventing war. Democracies are less likely to go to war with each other than non-democracies, as they share common values and interests. This was first proposed by Democracy in America (1835) by Alexis de Tocqueville, who argued that democracies are naturally peace-loving as they have no desire to conquest or dominate others. The democratic peace theory has been supported by numerous studies, including a famous study by political scientist Jack Snyder in 1991. Snyder found that out of all the major wars fought since 1815, none were between two democracies.

3. The realist perspective

3.1 The state as the main actor in war

Realism is the most dominant school of thought in international relations, and has been influential for centuries. Realists believe that the main cause of war is the nature of the international system itself. The international system is anarchic, meaning there is no central authority to enforce international law or keep order between states. This lack of rules and regulations means that states are free to act in their own self-interest, without having to worry about consequences from other states.

Realists also believe that states are the main actors in international relations, not individuals or NGOs. This is because states have more power and resources than individuals or NGOs, and are therefore more likely to be involved in conflicts with each other. Wars happen when one state perceives a threat from another state and decides to use military force to protect itself.

3. 2 The international system as a cause of war

Another key idea in realism is that the anarchic international system is a cause of war. Because there is no central authority to keep order between states, each state must rely on its own military power to protect itself from other states. This leads to a situation known as the security dilemma, where one state’s efforts to increase its own security can actually decrease security for other states. For example, if State A builds up its military, State B may feel threatened and respond by doing the same. This arms race can lead to a situation where both states are more likely to go to war with each other, as each feels less secure.

4. The identity theory perspective

4.1 Nationalism as a driver of war

Identity theory is a relatively new perspective in international relations, and is based on the idea that individuals identify with groups, such as nations or ethnicities. These group identities can be a strong driver of conflict, as individuals will fight to defend their group from perceived threats. Nationalism is one of the most important drivers of conflict, as it can lead to situations where one state perceives another state as a threat to its national identity. For example, this was a key factor in the First and Second World Wars, where various European nations fought each other due to nationalism.

4. 2 Other forms of identity

Nationalism is not the only form of identity that can lead to conflict. Ethnicity and religion are also important drivers of conflict, as they can lead to situations where one group perceives another group as a threat. For example, the Iran-Iraq war (1980-1988) was partly driven by religious differences between the two countries, as Iraq is majority Shia Muslim while Iran is majority Sunni Muslim. Similarly, the Djibouti –Ethiopia war (2008-2009) was partly driven by ethnic tensions between the Afar people in Djibouti and the Tigray people in Ethiopia.

5. Conclusion

In conclusion, wars happen for a variety of reasons, and no single perspective can provide a complete explanation. The liberal perspective highlights the importance of democracy in preventing war, while the realist perspective emphasizes the role of the state and the international system in causing war. The identity theory perspective focuses on the importance of group identities in driving conflict. Together, these three perspectives provide a more comprehensive understanding of why wars occur.


According to the realist perspective, the main causes of war are power and security. Realists believe that states are in a constant struggle for power, and that war is a natural extension of this competition. Security is also a key concern for realists, as states must protect themselves from the threat of other states.

The liberal perspective differs from realism in its explanations of war. Liberals believe that war is caused by economic factors, such as trade disputes or resource competition. They also argue that democracy promotes peace, as democracies are less likely to go to war with each other.

The implications of these differences for policymaking are significant. Realists tend to support policies that increase power and security, such as military buildups or alliances with other states. Liberals, on the other hand, tend to support policies that promote economic cooperation and democracy