What are the core differences between Classical Realism and Structural Realism (Neorealism)?

In International Relations for CUET PG, understanding the shift from Hans Morgenthau to Kenneth Waltz is fundamental.

1. Human Nature vs Systemic Anarchy:

• Classical Realism (Morgenthau): Rooted in human nature. States seek power because human beings possess an innate animus dominandi (lust for power).
• Structural Realism (Waltz): Rooted in the international system's structure. States seek power or security because the international system is anarchic (no central authority), compelling states to adopt self-help strategies.

2. Units of Analysis:

• Classical realists analyze the foreign policy behaviors of individual statesmen and regimes.
• Structural realists treat states as "billiard balls" (unitary, functional actors) differentiated primarily by their relative capabilities (distribution of power).