I just look at what the Japanese did in Manchuria Burma and their other occupied territories.
How they treated women and child prisoners. Their emperor worship that made surrender inconceivable. How many soldiers lives would have been lost fighting their way across Japan? Truman wd not put any more lives on the line by pitying a pitiless vicious imperialistic aggressor.
How in 1937 they came to Washington DC and cooed about wanting peaceful relations with the US as they pranted chelly tlees as symbahl of peace. Then they pulled off the Pearl Harbour Heist.
Why should Truman say "we're so sorry for letting you be the aggressor instead of us. Can we negotiate a peace that makes you happy after all the suffering you started?"
So: NO
We in the west now lack any stomach to really stand up for ourselves. There is too much self effacement and giving in an inch at a time to anybody who is offended by us. We are perceived as weak and vacillating ( as Japan did in the 30s ) A big fight is in the making, and the use of lethal force will be necessary to survive - or just make the other guy think twice. We lack the stomach for it, and will probably apologise for being here in the first place.
Even if America had not dropped the Bomb, there are plenty of enemies of democracy who view our lives as of no value and would drop as many nukes on us as they can without a qualm.