Realism emphasizes relation among nations as they have been and as they are.It is not concerned with the ideal world.It is the International interpretation of human behavior.

Realism or political realism as an approach of international relations has evolved over the centuries. Prominent among its earlier advocates were Indian scholar Kautilya, Chinese strategies Sun Tzu, and Greek scholar Thucydides, English philosopher Thomas hobbes also contributed to the evaluation of Realism. Their ideas may be called classical realism,though Morgenthau is now considered the principal classical realist. Morgenthau was the most systematic advocate of realism. However, British professor EH Carr writes: The “Twenty Years of Crisis” prepared the basis for Morgenthau’s development of the theory of realism. Realism is a school of thought that explains international affairs from the perspective of exercising power. The exercise of mutual power by the states is often referred to as realpolitik or simply power politics.

Hans J. Morgenthau:

Morgenthau from Germany could not tolerate the arbitrary domination and brutality of Hitler’s Nazi regime. He taught Americans national interests and established the “School of Realism in International Relations”. And for that he called it Political Struggle Power.Many Americans, obsessed with legalism and moralism, hated Morgenthau’s emphasis on national interests. However, it was only Morgenthau’s national interest that made sense in international affairs. He believed that “understanding national interests makes it easy to predict foreign policy movements.” He argued that “God is on that side,” that is, there is no universal morality. All government actions should be based on prudence and practicality.

Morgenthau equates what he calls “realism.” He believes that the flaws in the world are “the result of the forces inherent in human nature.” According to this approach to improving the WORLD, one must cooperate with these forces rather than oppose them. Like EH Carr, Morgenthau began his approach by defining a position against what he was seeing, if not the rule of the liberal utopian principle. Morgenthau listed six principle of political realism, which when taken together summarises his theoretical approach to the study of international relations. In the first chapter of his famous book “Politics among Nations”( 1948), Morgenthau states that his theory is called realism because it is concerned “with human nature as it actually is and with the historical process as they actually take place”.

Morgenthaus’s six principle of Realism- There are six principle’s of Realism

1.Politics is governed by objective laws which have their root in human nature. These laws do not change over time and are impervious to human preference. A rational theory of politics and international relations can based on these laws: infact any such theory should reflect these objective laws.

2. The key to understanding international politics is the concept of interest, defined from the perspective of power. By referring to this concept, politics can be regarded as an autonomous space of action. It imposes intellectual discipline on the viewer and gives a rational order to the political subject.

3. The form and nature of government authorities varies by time, place and situation, but the concept of interest is consistent. The political, cultural, and strategic environment greatly influences the form of power a state chooses to exercise, just as the types of power that appear in relationships change over time.

4.Universal ‘moral principles’ do not guide state behaviour,though state behaviour with certainly have moral and ethical implications. Individuals are influenced by moral codes but states are not moral agents.

5.There is no ‘universally agreed set of moral principles’ though States from time to time will endeavour to cloth their behaviour in ethical terms.

6.Intellectually, the political sphere is ‘autonomous’ from every other sphere of human concern,whether legal ,moral or economic. This enables us to see the international domain as analytically distinct from other fields of intellectual enquiry.