Question

Supporters of using the atomic bomb against Japan at the end of World War II thought an invasion would

Answer 1

Occur if not for the bomb, taking more lives than the bomb would.

Answer 2

The most important claim of supporters of the atomic bomb was that, taking such an extreme measure would force the Japanese Empire to surrender. This would avoid an innecessary invation of the Japanese territory, which would lead to an incredible loss of American lives.