With relevant examples describe the key differences between classical and structural Realism?

Classical realism and structural realism are two prominent theories in the field of international relations that provide different perspectives on the nature of the international system and the behavior of states. Here are the key differences between classical and structural realism, along with relevant examples:

1. Nature of the international system:
- Classical realism: Classical realists argue that the international system is anarchic, meaning there is no central authority to enforce rules and maintain order. They believe that states are the primary actors in international relations and that power is the main driver of state behavior. For example, Hans Morgenthau, a classical realist, argued that states are driven by their desire for power and security, and they engage in power politics to protect their interests.
- Structural realism: Structural realists, also known as neorealists, emphasize the structure of the international system as the main determinant of state behavior. They argue that the international system is characterized by a distribution of power among states, which shapes their actions. For example, Kenneth Waltz, a structural realist, argued that states are driven by the structure of the system, particularly the balance of power, and they seek to maintain their security within this structure.

2. State behavior:
- Classical realism: Classical realists believe that states are primarily motivated by their national interests, which are often defined in terms of power and security. They argue that states are rational actors that pursue their interests through strategies such as alliances, diplomacy, and military force. For example, during the Cold War, the United States and the Soviet Union engaged in a series of proxy wars and arms races to protect their respective interests and maintain their power.
- Structural realism: Structural realists argue that states are constrained by the structure of the international system, particularly the distribution of power. They believe that states are driven by the imperative of survival and seek to balance power to ensure their security. For example, after the end of the Cold War, many Eastern European countries sought to join NATO to align themselves with the more powerful Western states and enhance their security.

3. Role of human nature:
- Classical realism: Classical realists emphasize the role of human nature in shaping state behavior. They argue that states are driven by innate human characteristics, such as the desire for power, prestige, and security. For example, Thucydides, an ancient Greek historian, argued that the Peloponnesian War was caused by the fear, honor, and interest of the Athenians and Spartans.
- Structural realism: Structural realists downplay the role of human nature and focus on the systemic factors that influence state behavior. They argue that states are primarily motivated by the structure of the international system, rather than individual characteristics. For example, Waltz argued that even if states were led by different leaders with different personalities, the structure of the system would still shape their behavior.

In summary, classical realism emphasizes the role of power and national interests in state behavior, while structural realism focuses on the structure of the international system and the distribution of power. Classical realism attributes state behavior to human nature, while structural realism downplays the role of human nature and emphasizes systemic factors.