How did the existence of the atom bomb ultimately impact u. s.-soviet relations after world war ii?

When the United States dropped its atomic bombs on Hiroshima and Nagasaki, the Japanese finally surrendered and brought an end to World War II.  However, it deeply affected relations between the U.S. and Soviet Union.  The fact that America had a powerful weapon prompted the Soviets to create their own atomic bombs.  Though both sides had nuclear capability, neither used those weapons on each other.  Both knew the dangers of unleashing such weapons yet they both amassed large number of nuclear bombs and missiles started atomic diplomacy or having powerful weapons that they have in reserved in case the need for it arose.  Both sides almost came into conflict with nuclear weapons during the Cuban Missile Crisis when Russia moved missiles into Cuba thereby threatening the U.S. Eventually both sides came to an agreement and the crisis was solved.

Both countries had to aprove annexation.