It was completely unjustified. Here’s what I wrote 8 years ago:

August 6 was the anniversary of the first atomic bomb being dropped on Hiroshima, Japan. Tomorrow is the anniversary of the second bomb which was dropped on Nagasaki. Many great scholars have documented how this was unnecessary from a military standpoint despite the propaganda we’re taught in government schools. The invasion of Japan would not have cost “millions” of American lives. The Japanese would have surrendered had Harry Truman dropped his call for “unconditional” surrender which the Japanese took to mean the Americans would arrest and execute their emperor. Of course the president could have alleviated these fears & accepted their surrender. Instead he murdered at least 150,000 civilians, then let them keep their emperor anyway. Here are some quotes from contemporaries of Truman for those who still buy the lies:

“The Japanese had, in fact, already sued for peace before the atomic age was announced to the world with the destruction of Hiroshima and before the Russian entry into the war.” -Fleet Admiral Chester W. Nimitz

“It wasn’t necessary to hit them with that awful thing . . . to use the atomic bomb, to kill and terrorize civilians, without even attempting [negotiations], was a double crime.” -General Dwight Eisenhower

“On July 20, 1945, under instructions from Washington, I went to the Potsdam Conference and reported there to Secretary [of War] Stimson on what I had learned from Tokyo – they desired to surrender if they could retain the Emperor and their constitution as a basis for maintaining discipline and order in Japan after the devastating news of surrender became known to the Japanese people.” – Allen Dulles, chief of OSS operations in Switzerland