Duhhhhh!!!!!......The only other word for it is necessary.
Okay. To start it off, we, the U.S, gave Japan an uncountable amount of chances to surrender. Before they could even reject and continue to fight for their homeland, we warned them that if they don't surrender we would destroy it, their homeland. As anticipated, they again rejected and continued to fight. So although a little bit too harsh, we dropped an A-Bomb.