How did Hans Morgenthau contribute to classical realism?

Hans Morgenthau was a foundational figure in classical realism, primarily through his seminal 1948 work, Politics Among Nations. His contributions established a theoretical framework that defined international politics as being governed by immutable laws of nature, which states could navigate through rational, objective action.21

Key aspects of his contribution include:

• Power as the Central Goal: Morgenthau defined the national interest strictly in terms of power, arguing that all state actions are driven by the desire to keep, demonstrate, or increase it.2
• State-Centric Approach: He emphasized that international politics is a struggle for power among sovereign states, rejecting the identification of state moral aspirations with universal moral laws.2
• Critique of Idealism: He challenged the "idealism" of liberal internationalists, arguing that attempts to reform the world through international institutions or ideological crusades (such as spreading democracy or communism) ignore the realities of human nature, which is inherently inclined toward competition.23
• Diplomacy: He advocated for the use of traditional diplomacy and compromise to manage the inherent limits and nature of power.2