Politics Among Nations: The Struggle for Power and Peace is a political science book by Hans Morgenthau published in 1948. The book introduces the concept of political realism, presenting a realist view of power politics. This concept played a major role in the foreign policy of the United States, which made it exercise globe spanning power in the Cold War period. The concept also called for a reconciliation of power politics with the idealistic ethics of earlier American discussions about foreign policy.