Some bleeding hearts tried that ca 1950 and the most popular answer was "Why did you drop only two?"
In reading some of the many WWII books I found out:
1) After the war, an American diplomat was talking to one of his Japanese counterparts about the atomic bombings. The Japanese guy said that they had to give up as they didn't want us to drop any more. When the American told him that that was all we had, the reply was "If we knew you only had two . . ." and then thought better of it and clammed up.
2) A Japanese general on the mainland was giving a pep talk to his troops that went something like this: "Yes, things look bad now, but if we we redouble our efforts, we can still win the war." This was AFTER Nagasaki.
3) It was found that the Japanese prison camp commander were told that when the heard that the mainland was invaded, they were to "take care" of all allied prisoners in any way they deemed best. (Think Palawan, Philippine Islands).
4) Allied prisoners were dying at the rate of 1,000 a day. I defy anyone who says that we should have starved Japan into surrender to get before an audience of families who had relatives in the war and explain to them why they should be sacrificed because the Bomb was inhumane. A corollary of that is to ask them how long Truman/Democrats would have lasted if it was known we had a way to quickly end the war and didn't use the Bomb for that same reason.
[sidebar] Some years back, The Seattle Times had a boo-hoo article about the dedication of a park monument in honor of a six-year-old girl who died at Hiroshima. I wrote the reporter and asked her when they would dedicate a monument to a six-year-old girl who died in the Pearl harbor bombing. She wrote back that she wasn't aware that they were civilian casualties there.
And it saved Japan from being divvied up into two, like Germany and Korea.
Has Seattle torn down their statue of Lenin?