The end of the World War II in 1945 was the beginning of the Cold War between the United States of America and the Union of Soviet Socialist Republics. It was necessary for military scientists to consider how to control nuclear weapons that superpowers developed in World War II. The nuclear weapons changed the strategic condition of the possible war. Military theorists had to consider how to avoid nuclear war and how to deal with nuclear strategy. Bernard Brodie, a military scientist in the United States, suggested to change the purpose of the military forces to deterrence from victory in his book "The Absolute Weapons". The idea of deterrence is to control enemy nuclear attack by letting the enemy know his risk of nuclear counterattack. Military science is no longer for military operations, but for the whole of the national security policy. Basil Henry Liddell-Hart, British military strategist, also said the old idea of strategy is narrow to use in nuclear age. His discovery was the idea of strategy can be used in matters of national security. This kind of strategy called grand strategy, or national security strategy spread for military theorists today.