Realism has been the most important approach of international relations over the years. It has been the dominant way of explaining international behaviour. Realism emphasizes relations 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 behaviour. Individuals are essentially selfish, and they seek power to serve their interests and to prevail over others. As Morgenthau wrote in the 20th century, power is the control of men over the minds and actions of other men. And, there is constant strife leading to conflicts and clashes between individuals having divergent interests and seeking to acquire power. Thus, there is an ever-present struggle for power in the society. The same is the tone of nations that are guided by the same considerations as individuals.

Political Realism
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 strategist Sun Tzu, and Greek scholar Thucydides. Much later, Italian scholar Nicolo Machiavelli and English philosopher Thomas Hobbes also contributed to the evolution of realism. Their ideas may be called classical realism, though Morgenthau is now considered the principal classical realist. However, according to the view expressed by Robert Jackson and George Sorensen (1999) and many others, Morgenthau’s theory may be described as neo-classical realism. But, Morgenthau was the most systematic advocate of realism. However, British Professor E.H. Carr, who wrote The Twenty Years’ Crisis (1919-39) had prepared the ground on which Morgenthau developed his theory of realism.

Carr criticized democracies like the UK and France for their failure in defeating the designs of dictators. He blamed the democratic countries for failing to recognize the power realities in the world. Carr divided the scholars of international relations into two groups. These were ‘utopians’, or ‘idealists’, and the ‘realists’. He described the utopians as optimists- children of enlightenment and liberalism. The liberals held the view that reason and morality could structure international behaviour of the states towards peace. Wilson and (his) League of Nations were cited as main examples of utopians. Carr, who himself was a a realist, described realists as pessimists, or children of darkness, who emphasize power and national interest. Commenting on Carr’s views on power, Michael G Roskin and Nicholas O Berry wrote, ‘This does not necessarily mean perpetual war, for if statesmen are clever and willing to build and apply power, both economic and military, they can make the aggressors back down…’

Political realism is a significant theory in the field of international relations that seeks to explain state behavior under a set of specific and rigid assumptions. At its core, political realism is guided by three S’s: statism, survival, and self-help.

Statism asserts that states are the only entity on the international stage that matter and that they are unitary (acting alone) and rational (acting in its best interests) actors. Survival identifies the state’s primary goal is to survive in an international system characterized by anarchy. The final S, self-help, conveys the assumption that states cannot trust others in their pursuit of survival and must secure their security.

Political realism is further delineated into sub-theoretical frameworks, including:

Classical realism
Liberal realism
Neoclassical realism
While each sub-framework has its own nuance within the broader political realist theory, all forms of political realism fundamentally believe world politics is a field of conflict among states pursuing power.

Structural Realism
Structural realism, also referred to as neorealism in the academic community, is a major branch of political realism derived from classical realism. While the latter incorporates analysis of human behavior within state decision-making, structural realism focuses predominantly on the anarchic structure of the international system. In other words, structural realists see global conflict as inevitable because there is no supranational body that could prevent or mediate conflict between individual states. Therefore, structural realists assume that states must always be preparing for conflict because war could break out at any time.

Structural realists believe that understanding the international system is guided by the three S’s of political realism. However, they do incorporate analysis of inter-relationships between distinct state entities, particularly regarding power relationships. A key concept in structural realism is polarity, the balance of power within the international system. Today, international theorists often describe the world as unipolar, with the United States acting as the sole superpower endowed with the ability to dominate international relations via their economic, political, and military supremacy.