President Truman was justified in using the atomic bomb against Japan in WWII because it put an end to the war, put an end to Japan and stopped them from creating war again, it was able to save thousands of lives. The first reason to use the atomic bomb is to put an end to the war, saving thousands of lives. It says in document 5 by Henry Stimson, this stopped fire raids and strangling blockages and ended the clash of armies on land. By launching the atomic bomb, it had ended battles that were happening and were going to happen, saving people’s lives. The next reason to use the atomic bomb is because it was able to stop Japan’s power. According to document 2, Harry Truman said “we shall destroy their docks, factories, and their communities.