After four years of war, after the collapse of the Third Reich in Germany, Americans were understandably eager to see the conflict in the Pacific come to an end. That leaflet was meant to amplify the terrifying effect of the atomic blasts, but one can also sense the pride involved. It's a punctuation mark on a long, bloody conflict, the final celebration of a game which was already settled.
In a Gallup poll taken in early August of that year, days after the two bombings, 85 percent of Americans expressed approval of the use of the atomic weapons. Over time, the percentage approving has dropped, but Americans still generally see their use as a positive — in part because they see the detonations as having helped to hasten the end of the war. (This is contested.)
(An interesting note: In later years, polling on this question began with "As you may know, the United States dropped atomic bombs on Hiroshima and Nagasaki in August 1945 near the end of World War II." In the first poll, in 1945, the question was, "Do you approve or disapprove of using the new atomic bomb on Japanese cities?")
Attitudes toward the development of nuclear weapons, however, have changed much more dramatically.
Gallup asked Americans shortly after the Japanese surrender if they thought development of atomic weapons was a good thing. At that point, nearly 7 in 10 said it was. But when asked a half-century later, sentiment had flipped.
There is a huge number of reasons why that change has occurred. The weapons under consideration in 1945 were vastly different than those in 1998; the political considerations over their use were far different, too.
It serves as a good reminder, though, that the America and Americans making decisions in 1945 were approaching the bombing of Hiroshima and Nagasaki from a much different perspective than we are today. At the time, there was enormous political and military will to demonstrate the nation's strength. Considering that demonstration after the fact necessarily means considering it differently.