I would say the opinion is up to you to decide,since everyone has different opinion on it,however I can give you some ideas:
Yes:Japanese bombarded America and caused heavy loss, the drop of atomic bomb was to stop Japan from attacking,if the atomic bomb was not dropped,the war would continue for a longer period of time resulting more deaths and injuries of Americans
No: Although Japan dealt a heavy blow on US, many of the civilians on Hiroshima and Nagasaki were innocent and were not involved in the war yet had to take up the consequences of their notions attacking US, the two places were completely destroyed by the atomic bomb and many suffer from the aftermaths
