Perhaps. But what if the church had to decide the question: Which is most moral: to drop the bomb and kill 45,000, continue the firebombing (80,000 in Tokyo alone), or invade and kill ten times more, which is most moral?
I think I'm right.
And you can be a Protestant too.
The Catholic Church condemns this definitively in Gaudium et Spes,(Constitution on the Church in the Modern World) Para 80:
"With these truths in mind, this most holy synod makes its own the condemnations of total war already pronounced by recent popes, and issues the following declaration:
"Any act of war aimed indiscriminately at the destruction of entire cities of extensive areas along with their population is a crime against God and man himself. It merits unequivocal and unhesitating condemnation."