The atomic bomb
Dropped on japan Hiroshima on 1945 6th of August, by President Truman.
The first decision
Japan attacked japan and destroyed the navy battle ships in the area. This made Truman mad and he told japan to surrender because he said if they didn't america would invade.
The second decision
After days of talking to scientists, prime ministers and mayors, Truman finally decided that they were to drop the newly made and recently tested "Houston project" also known as the atomic bomb instead of an invasion.
Japans tradition was to never back down and surrender