  Hans J. Morgenthau (1904–1980) developed realism into a comprehensive international relations theory. Influenced by the Protestant theologian and political writer Reinhold Niebuhr, as well as by Hobbes, he places selfishness and power-lust at the center of his picture of human existence. The insatiable human lust for power, timeless and universal, which he identifies with animus dominandi, the desire to dominate, is for him the main cause of conflict. As he asserts in his main work, Politics among Nations: The Struggle for Power and Peace, first published in 1948, “international politics, like all politics, is a struggle for power” (25).