There are two approaches to the study of International Relations: idealist and realist.
The Idealist approach is as old as war: man has always dreamed of a world in which there would be no war between nations and peoples, States and countries. Great thinkers, teachers, and preachers have always laid emphasis on relations of peace, human love and amity. Immanuel Kant, the great German philosopher, was the first to write on a programme of world peace. Modem writers on International Relations believe that to promote world peace and intentional understanding and for the growth of internationalism among the peoples and nations of the world, one should study how men and groups ought to behave in international relations, rather than how they actually behave.
They believe that the moral rules and virtues, like human love, and fellow-feelings, justice and freedom and the natural desire of the mankind for peace, are powerful forces, if only the governments would create conditions and atmosphere for world peace and disarmament. It may be remarked that idealist approach is more emphasised in international relations than in the internal politics of the various States and countries. It would be more useful if the nations and States of the world first established love and goodwill at home as a preliminary to world peace and understanding. Ethnic disputes, religious persecutions or communal riots are neither good for a country, nor for world peace.
The idealist thinkers like the American Hans Morgenthau, believe that power and self-interest are the motive forces in international relations and dealings. The realist approach is a more modern view, but it has not discredited the earlier idealist approach. This approach is the result of three important events; the failure of the League of Nations (1919-1939), the outbreak of the Second World War (1939-1945) and the so-called Cold War between the two superpowers, U.S.A. and the U.S.S.R., which have raged between them on and off since 1948. The realist thinkers declare violence and conflict as inevitable, which can be controlled by skilful diplomacy and by maintaining “positions of strength” in international relations and dealings. In other words, the realist1 -emphasise that governments and nations should play the game of power in the international world.