During last 50 years of development, the nuclear bomb, as the ultimate weapon became the peacekeeping force on the earth. The nuclear bomb was developed in Manhattan project during the WW II and was successfully tested in the New Mexico on July 16 1945. At this point started the change of nuclear weapon from ultimate weapon to political weapon. USA decided to use the atomic bomb to defeat Japan in order to save around 500.000 lives of American soldiers that were needed to end the war and in the summer 1945 the USA dropped two bombs on Hiroshima and Nagasaki. The nuclear weapon raised the confidence of USA but president Truman did not ordered its mass production because at that time he saw no explicit political function for the bomb. USA even tried to internationalize control of the bomb under the UNITED NATIONS but the Soviets were reluctant to support American plan for two reasons. To stop soviet nuclear program before developing the first soviet bomb would give Americans permanent lead in nuclear weapons technology. Soviets believed that instruments of force always have political capabilities. For the Kremlin weapons were political tools. This led Americans to the same conclusion. The beginning of Cold War created several political functions of nuclear weapons: nuclear deterrence, alliance building, and international prestige.
The Nuclear Bomb was developed as the weapon of war at the end of the Second World War. Nuclear Deterrence was than the natural function of nuclear bomb. The atomic bomb had a function of "natural deterrence" at the early beginning of Cold War when Soviets did not have nuclear weapons. The Soviets would not attack West Europe because they would risk war with USA and USA had atomic bomb that was seen by Soviets as the essence of deterrence. USA also believed that if Soviets finish their own bomb they would not be deterred by USA and its nuclear arsenal therefore the West Europe would become vulnerable.