The dropping of atomic bombs on Japan was justified for the following reasons.
First, the island hopping strategy was incredibly deadly; the Japanese fought mercilessly on each island as the United States got closer to the Japanese mainland. Furthermore, it was projected that the impending invasion of the Japanese mainland, and the war that had been going on previously between the United States and Japan, would be so deadly that approximately 1,531,000 Purple Hearts were created. Had the United States not dropped the atomic bombs on Japan, the death toll would have been catastrophic in comparison to what it ended up being at the end of the war.
Next, Japan had no intentions of surrendering and the war had already proven to be disastrous for citizens living in war-ravaged areas. Examples of this include Stalingrad and Warsaw. It would have been detrimental not only to the Japanese and United States militaries, but to the citizens of Japan and potentially the United States. While the atomic bombs dropped on Nagasaki and Hiroshima did cause a huge amount of death and devastation for the two cities, fighting all the way up the Japanese mainland would have proven to be far worse.
Finally, the atomic bombs offered a quick and effective end to the war. World war II is still the deadliest conflict in history, and it has already been going on for almost 6 years by the time the U.S. decided to drop the atomic bombs on Japan. Had the war dragged on even longer, there would have been a risk of future conflicts igniting between other nations, initiating an entirely different war that would have gone on for months or years longer than September, 1945.
I hope this is good enough lol i just finished my World War II unit and am trying to remember things