The history of Cold War nuclear weapons dates back to World War II, when the United States dropped two nuclear bombs on Japan. While these were the only two nuclear bombs to be used during active warfare, their use spawned a nuclear arms race that lasted for more than half a century. The Cold War nuclear weapons race was primarily a contest between the United States and the Soviet Union, though other countries developed nuclear weapons during this time.
After World War II, the struggle for world power erupted and the United States and the Soviet Union took the lead. At the time, the United States felt they had a monopoly on nuclear weapons and access to the only stockpiles of uranium, which was necessary for making the nuclear weapons. The world soon discovered that uranium was not as scarce as the Americans thought it was, and soon the Soviet Union began developing their own Cold War nuclear weapons. They completed their first nuclear weapon earlier than the United States predicted, which came as a shock to the world. Since the United States had been wary of the Soviets even during World War II when the countries were allies, this development caused much fear in the United States, further fueling the Cold War and the Red Scare in the U.S.
The Soviet Union's first Cold War nuclear weapons were almost identical copies of the bomb called Fat Man, which was the American nuclear bomb dropped on Nagasaki. After this development, both sides stepped up their production of nuclear weapons, realizing that the future of nuclear weaponry was in missiles, not bombs. Missiles had long range impact, and when the Russians launched Sputnik, displaying their technological advances, the space race began and the United States recognized that Russia was ahead of the game in terms of creating nuclear missiles.
However, both sides who had developed Cold War nuclear weapons had also developed "second strike" systems, which basically meant that even if one side had been attacked and mostly destroyed, that side could still launch an offensive and obliterate its enemy. Therefore, both the U.S. and the Soviets knew that if they launched an attack, it meant devastation for both sides.
As more countries, such as France, the U.K., and China, began developing their own stockpiles of Cold War nuclear weapons, treaties began forming to slow or halt proliferation of nuclear weapons. While many of these treaties were ineffective, the United States lacked confidence in their own weapons and were eager to slow the pace of proliferation around the world. The Soviet Union was experiencing economic problems, which led to a slowdown of nuclear proliferation on their end. By the time Ronald Reagan took office in the United States, the Cold War was coming to a close and a conglomeration of treaties and agreements had slowed nuclear developments. However, in recent decades, other countries have begun building their own nuclear weapons, reawakening the issue of nuclear war and its economic and humanitarian impacts.
