After five years of speaking to audiences across the country about the 1945 U.S. atomic bombing of Nagasaki, the subject of my book, I can hardly tolerate another person saying to me — sometimes yelling at me — that “the bomb” ended the war. That it saved 1 million American lives (or some variation on this number) by avoiding an Allied invasion of Japan. Or that we had to drop the bombs because Japan was never going to surrender.

People point, with understandable outrage, to the atrocities of Japan’s military, including its attack on Pearl Harbor, its monstrous brutality against Chinese civilians, and its torture and killing of Allied prisoners of war. Some even go so far as to say that the Japanese deserved what they got. Many believe that even discussing what happened to the victims of the atomic bombs amounts to an undeserved apology. Still others argue that my focus on the survivors vilifies the American veterans who fought and sacrificed in those final months of the war, and devalues the lives of soldiers who might have died in an invasion. Whatever their objections, their tone is often aggressive and angry, an insistence that the central concern is the necessity of the bombing 75 years ago, not the people of Nagasaki.

For generations, Americans have been frozen in the debate over the “necessity” of the bomb, allowing us to ignore — even deny — its human impact. From the very beginning, U.S. officials promoted this denial by withholding critical information and distorting key facts to cast the bombings as vital, and inevitable, military actions. After the war, U.S. leaders censored the Japanese press from reporting on Nagasaki and Hiroshima, limited American media coverage of the human impact of the bombings and denied the unspeakable suffering and death caused by high-dose radiation exposure.

Starting in 1946, top U.S. officials devised a campaign to quell growing public criticism of the bombings and to promote public support for further U.S. nuclear weapons development. In the words of Supreme Court Justice Felix Frankfurter, a longtime friend of former secretary of war Henry Stimson, the government needed to quell the “sloppy sentimentality” of any dissenters. In the December 1946 issue of the Atlantic Monthly, Karl T. Compton, the president of MIT and a respected physicist who had helped develop the atomic bombs, provided inflated casualty estimates for a land invasion, argued that using the bombs was the only rational choice and pointed to the emperor’s decision to surrender less than a day after the Nagasaki attack as evidence that the atomic bombs ended the war.

The campaign culminated in an extended article on the decision to use the bomb written by Stimson, published in Harper’s Magazine in February 1947 and filled with critical misstatements and omissions. Stimson failed to mention, for example, that U.S. officials had debated dropping their demand that Japan’s surrender include the removal of the emperor, which Stimson himself had recognized as a possible way to bring Japan to an earlier capitulation. Stimson also omitted the most critical military development in August 1945: the Soviet Union’s entry into the war against Japan, which would have forced Tokyo to fight on two fronts, altered Allied strategies and probably ended the war before any land invasion. Through his military authority and strategic reasoning, Stimson forged a singular atomic bomb narrative with such moral certitude that it has superseded all others and fundamentally shaped American memory and perception ever since: The atomic bombings ended the war and saved more than 1 million American lives.

But there is no historical evidence that the Nagasaki bombing helped bring about Japan’s surrender. Before the nuclear attack that morning, Japanese leaders were already panicked over the Soviet Union’s massive invasion of Japanese-held Manchuria, 11 hours earlier. As the mushroom cloud rose high above Nagasaki, Japan’s leaders were already in a heated debate over whether to surrender and under what conditions; the news of the second atomic bombing had no apparent impact on their deliberations, which, according to notes from their meeting, continued throughout the day and evening with no further mention of Nagasaki. Late that night, the emperor broke their stalemate by sanctioning the surrender.

The real problem, however, is that debating the necessity of the bomb keeps us from confronting far more pressing questions: Even if both atomic bombings could be linked definitively to Japan’s surrender, were these mass killings and irradiation of civilians “right”? And what are the implications of continuing to accept our country’s official narrative?

In Nagasaki alone, 74,000 people died by the end of 1945, when the first count was possible. Only 150 were military personnel. Seventy-five thousand more civilians were injured or irradiated. In Hiroshima, another 140,000 were killed. If we justify their deaths, injuries and irradiation, where do we draw the line? Exactly how many civilians in any conflict are we willing to sacrifice to achieve military victory?

Is it, for example, acceptable to purposely sear the face and body of a 13-year-old boy? Or for a teenage girl to find the charred body of her 9-year-old brother, recognizable only by the name tag on his shredded school uniform? Or for a 12-year-old, who was not injured in the atomic blast, to fall sick a month later with fever, bleeding gums, hair loss and telltale purple spots all over her body — and then writhe in pain for a week before dying? Or for thousands more to experience and die of the same agonizing symptoms, all signs of instantaneous, whole-body radiation exposure in doses higher than any human had ever received?

Is it right that pregnant women whose fetuses were exposed in utero suffered spontaneous abortions, stillbirths and infant deaths, and many babies who survived birth developed physical and mental disabilities? That people lived in the ruins for years, in flimsy shacks built on top of charred fragments of human bone, caring for their injured, irradiated and dying loved ones even as they themselves were often injured or ill? That, three years after the bombing, cancer rates began to soar, and by the early 1950s many hibakusha — “atomic-bomb-affected people” — developed liver, endocrine, blood and skin diseases, and impairments of the central nervous system? Thirty years after the war, high cancer rates persisted. Even today, radiation scientists are studying second- and third-generation hibakusha for genetic effects, reminding us how much we still don’t know about the insidious nature of radiation exposure to the human body.

I mourn the U.S. military personnel who died in the Pacific theater and would not want even one more U.S. or Allied soldier to have died. If we engage in war, though, our moral obligations do not stop at saving as many of our own soldiers as possible. We also have a responsibility to, at all costs, avoid harming or killing civilians. These are the basic, sometimes wrenching and widely-agreed-on ethics of war.

By insisting on the “necessity” of the bomb, we fail to recognize the immorality of the intentional mass killing and maiming of civilians. We betray history when we treat the use of nuclear weapons on Japan as inevitable. We allow ourselves to maintain a comfortable distance — even a sense of moral superiority — when weighing the fate of entire cities in a nation we called our enemy. And we accept as normal the current existence of more than 13,000 nuclear weapons across the globe (most far more powerful than those used on Japan) and tacitly sanction the future use of these instruments of mass terror. It’s time to face what happens to a child, a family and a city split in two by nuclear war. This is what hibakusha can teach us, if we dare to listen.