Answer: Setting the stage for the Cold War
Explanation:
The atomic bomb and Korea set the stage for the Cold War after World War II.
The atomic bomb sent a message to the world that the most admired and most powerful nation, the USA, believed that nuclear weapons were legitimate instruments of war and could be used again.
Right after WWII, the Korean peninsula was split into two countries. Korea set a conflict between the communists and the West. Korea played this role most clearly in the Korean War that lasted from 1950 until 1953.