Two widely renowned and opposing philosophies of what can be an accurate predictor of world politics are known as realism and liberalism. Overtime, these particular schools of thought have developed into strategic sciences; and two notable, ground-breaking theorists include, Hans Mogenthau and Immanuel Kant, respectively. Both international relations theorists make note of the inevitability of conflict among states yet have thus created the foundation for the basic principles that have since allowed their philosophies to expand. However, there are certainly many differences to the approach of understanding international relations that these scholars helped create. In terms of realism, Hans Morgenthau argues that the most important actor in international relations is the individual state. He focuses less on morality and more on the rationality for states to gain the most power when standing against other nations. And, in order to achieve this, little to no change must occur within human nature. Also, he promotes the insignificance of the states' domestic political system. In contrast, liberal theorist, Immanuel Kant, focuses on the importance of cooperation and security among states in order to achieve peace among nations; and he stresses that, ideologically, all states should be republics. Definitively, Morgenthau and Kant argue opposing political theories, yet their most fundamental differences include how to maintain power and the relevance of a state's domestic political system. .
In terms of realism, human nature is the root of what governs the behavior of a nation. Morgenthau states that human nature "has not changed since the classical philosophies of China, India, and Greece endeavored to discover these laws" (AJ 2013, 15). Therefore, this political theory's historical foundation acts as a virtue. Above all, Hans Morganthau, places individual state's own interest over many other moral factors on the international scale.
