Introduction The reason why the United States was compelled to employ the use of a more lethal weapon in Hiroshima and Nagasaki in Japan has been at the heart of many scholarly writings. The question is, why did the United States decide to engage a deadly attack and yet there was a league of nations charged with conflict resolution? The idealists came up with an international organization in the name of the League of Nations to address problems of war. The use of atomic bomb therefore was shaped by international variables such as scientific research and discoveries. Causes to any phenomena are multi-dimensional meaning that they should be studied in a multi-disciplinary way such as geographically, psychologically, politically and economically. It therefore follows that causes to the use of atomic bomb in Japan should be divided into particular and profound causes. Particular causes are those that are immediate while profound causes are underlying issues. Historians are interested with immediate causes of war while political scientists try to explore long-term causes but both will be dealt with in this study. 1 Taylor examined that war is like a road accident because it has the immediate causes such as over speeding as well as long-term causes such as the nature roads. Scholars have been interested in both immediate and underlying causes for application of atomic bomb in Hiroshima. The application of the strategy did not have a single cause because WWII had roots in the society and the then international system. Quency wright in his works about study of war vol.1 (1942) observed that war has multi-causal factors, arguing that war in reality results from a total situation involving ultimately almost everything that has happened to the human race up to the time war is realized. Kennedy Wolfs in his works ‘Man, the State and war’ gives three images of war based on assumption that war results from human nature, internal nature of the state and anarchic nature of the international system. 2 War is as old as human existence and characterizes the nature of human beings. A clear relationship exists between human nature and conflict. ST Augustine claimed that war is part of society and human life because of sin, man exhibits love for hurtful things and vain which constitutes the source of human conflict. Benedict de Spinoza observes in a short article called political treatise that war occurs because man is led by passion not reason hence there is a conflict between passion and reason. Rein Niebuhr in his works ‘Beyond Tragedy’ argued that war comes from the dark unconsciousness sources of the human psyche. Confucius on his part postulated that there is deceit and cunningness among human beings leading to war thus war is an innate factor in human beings. John Stoessinger claimed that people are victims of their own perceptional limitations because they are limited in their comprehension of natural phenomena and hence are bound to make wrong judgments. 3 This paper examines the particular and profound causes that made the United States to utilize the atomic bomb in Japan. The leaders’ idiosyncrasies and the nature of societal variables such as natural resources and geographical territories are explored in detail. Particular Causes End of World War Two The United States applied atomic bombs on Japan in order to force the