Final answer:
President Truman decided to use atomic bombs against Japan because he wanted to quickly end the war and avoid high casualties in a conventional invasion.
Step-by-step explanation:
The most likely reason President Truman decided to use atomic bombs against Japan was because he feared the loss of life that would be involved in a conventional invasion of Japan. The atomic bombs were seen as a way to quickly end the war and avoid the high casualties that would come with a traditional ground attack. By using the atomic bombs, Truman hoped to force Japan to surrender and bring an end to the war.
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