And thank God he did. Hiroshima and Nagasaki saved millions of lives. Had the war not ended when it did millions of Japanese would have starved to death not to mention the soldiers who would fight to the death costing the US hundreds of thousands of casualties.
Like Sherman said “War is Hell.”
Yes, but we are not G-d, Who is in charge of Hell. War is what it is. Civilized countries put boundaries on war. Removing those boundaries cannot be justified by “saving lives,” unless one side becomes irrational in its pursuit of victory, and extreme measures are needed to counter their extremism.
You can thus make the argument that Hiroshima and Nagasaki saved lives only because the Japanese were fanatically launching suicide attacks and would not give up despite the fact that they were clearly beaten.
But you cannot make that argument with regards to the scorched earth regimen that Sherman instituted in the Shenandoah Valley (did I really say Susquehana before? Oops.) and Atlanta, because the Confederates were fighting bravely and skillfully in a civilized manner (for the most part). So, too, did the Boers fight a guerrilla hit-and-run campaign, which is legitimate and worthy of respect, so long as it’s fought against uniformed combatants and not civilians. But Lord Kitchener instituted scorched earth and confined to concentration camps their women, children and servants, who were systematically starved.
An enemy that respects the laws of war and fights bravely deserves to have those laws respected regarding his property and family. The Confederates did observe the laws of war. So did Grant’s army, only he consistently won, which was a new thing for the Union. Sherman’s did not, which retroactively provided some legitimacy to the secession idiocy which sparked the war in the first place.
Japan, which interests you, is subject to the same argument, except there the Japanese fanaticism and refusal to face reality made the Bomb a legitimate option, when all considerations in this argument were weighed. But Sherman made war more Hell-ish than he had a right to do, and thereby gave his adversaries a sense of justification which itself encouraged them to fight on, thereby costing lives.