The use of atomic bombs on Japan to hasten the end of World War II propelled the United States to its status as a superpower. Testing and explosion of the atomic bomb by the Soviets in 1949 established the Soviet Union as a second superpower.How did possession of nuclear weapons change warfare in the Cold War period? *
A. Nuclear stalemate led to the use of brinkmanship to avoid mutually assured destruction.
B. After the United Nations banned the nuclear weapons, they fell out of use in modern warfare.
C. The United States and the Soviet Union both sought to share their nuclear technology with many of their allies.
D. Warfare became more immediate, and many examples of direct conflict between the United States and the Soviet Union occurred.

Although both US and the Soviet Union emerged victorious in World War II, political differences between them soon grew into open but limited rivalries and hostilities, which, despite the constant threat of war, never developed into a comprehensive military conflict.
By 1949, the world was roughly divided between pro-Western and pro-communist states. The allies of the two opposing parties waged wars on their behalf, such as those in Korea (1950-1953) and Vietnam (1955-1975), while both America and the Soviet Union accumulated huge arsenals of nuclear and other weapons.
Attempts to reach an understanding between the two conflicting parties failed in the 1970s. By the late 1980s, America had outpaced the Soviet Union in its allocation of nuclear weapons and pushed the Soviets toward financial ruin, leading to a series of arms reduction agreements in 1988 and 1991.