Question

What was an argument used in favor of dropping atomic bombs on Japan?

Answer 1

It would limit casualties of American troops as opposed to a full scale invasion of the island.

Answer 2

The initial approved casualties forecast of U.S troops done by the Joint War Plans Committee ranged from 130,000 to 200,000, but latter after the Japanese reinforcement efforts the numbers increased to 1,7 million to 4 million; this led to a change in the strategy since the numbers now represent too great of a loss for the U.S army.