Atomic Salvation: Did The Atom Bombs Save 500,000 To 32 Million Lives?

By Joshua Mawhorter, Mises Wire | December 07, 2024

“I wanted to save a half million boys on our side.... I never lost any sleep over my decision.”—Harry Truman, (quoted in Alfred Steinberg, The Man From Missouri (New York, 1962), p. 259)

It is estimated that there were 416,480 American military deaths in WWII. Thus, what we are invited to believe by Truman’s assertion that the atomic bombs saved 500,000 (or many more) American lives is that, had the US invaded Japan, more Americans would have died in such actions than in all the theaters of WWII combined. Further, that prior to the bombs, Truman, Stimson, and Marshall would have approved an invasion plan (as those of Honshu and Kyushu) had they actually believed that 500,000 American deaths would have resulted, as opposed to more likely alternatives prior to invasion.

The Bomb and Big Fish Stories

Like the tendency of “who-caught-the-biggest-fish” exaggerations to grow with each next story, it seems that the numbers of the American lives supposedly saved by the alternative of the atomic bomb seems to grow with each retelling!

James B. Conant—wanting to get ahead of the story—convinced Secretary of War Stimson to publish an article justifying the use of the bomb. In the article in Harper’s (1947), it was claimed that the bomb probably prevented “a million more” American casualties. However, in 1946, the United States Strategic Bombing Survey published the following assessment,

Based on a detailed investigation of all the facts and supported by the testimony of the surviving Japanese leaders involved, it is the Survey’s opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated. (emphasis added)

In light of this early post-war evidence, it is doubtful that such a defeated force could have caused 500,000 American deaths or more. Shortly following Nagasaki, Churchill claimed that the bombings saved well over 1,200,000 Allied lives. In 1953, Winston Churchill wrote, “To quell the Japanese resistance man by man and conquer the country yard by yard might well require the loss of a million American lives and half that number of British…” (emphasis added). This was based on memories of the Battle of Okinawa (65,631 casualties; 7,374 deaths), thus, nowhere near 500,000 American deaths, let alone “a million.”

While in the White House, Truman usually placed the number of American lives saved around 250,000, and occasionally around 200,000. After leaving the White House, Truman began upping the number to 300,000 lives in the first drafts of his memoirs. In 1955, Truman penned his Memoirs and, in volume 1—Year of Decisions (1955)—he wrote, “General Marshall told me that it might cost half a million American lives to force the enemy’s surrender on his home grounds.” Truman also wrote a letter in 1953 that appears in The Army Air Force in World War II, Vol. 5, The Pacific, Matterhorn to Nagasaki, June, 1944-August, 1945, in which he stated,

I asked General Marshall [at Potsdam] what it would cost in lives to land on the Tokyo plain and other places in Japan. It was his opinion that such an invasion would cost at a minimum a quarter of a million American casualties, and might cost as many as a million, with an equal number of the enemy. The other military men agreed. (emphasis added)

Note that Truman admits that General Marshall spoke of casualties, not deaths. Based on the average ratio of casualties to deaths in the Pacific, this would entail about 50,000-250,000 deaths, not the 500,000 Truman would later claim in 1955. For those and other reasons, Barton J. Bernstein argues that, “The claim of half a million was a post-war creation.”

Even though the claim of 500,000 American lives saved by the avoidance of invasion because of the atomic bomb was unwarranted, the counterfactual numbers of lives allegedly saved by the atomic bomb continued to grow. A sampling of secondary school textbooks reported that invasion, instead of the bomb, could have caused the loss of one million American lives. In the Washington Post (December 1, 1991), President George H. W. Bush claimed that the atomic bombs “spared millions of American lives.” Finally, Tom Lewis wrote Atomic Salvation: How the A-Bomb Attacks Saved the Lives of 32 Million People—described in a sympathetic review as assuming the dichotomy between atomic bomb or invasion without other options, as lacking an index, limited to only English-language sources, mainly built off of secondary works, and using primary sources that provide little insight into American decision-making—counting the total lives saved—American, Japanese, and others.

Alternatives and Worst-Case Scenario

While such counterfactual claims of lives saved may seem plausible given the viciousness of Pacific warfare, and while we should not fault anyone for a wrong estimate in general, and while history ought to be fair to what was known at the time, the confident claims of 500,000+ American lives saved by the atomic bomb are not only dubious, but were directly contrary to the evidence and estimates at the time. There were various invasion scenarios and, at worst, the American death estimates did not even come close to 500,000. Much of this evidence was unearthed by Gar Alperovitz in his Atomic Diplomacy (1965) and subsequent scholarship.

In June 1945, US military planners estimated that, in the worst-case scenario, the most American deaths in an invasion plan amounted to 46,000. On June 15, 1945, the Joint War Plans Committee (JWPC) projected estimates for three invasion scenarios—1) an attack on southern Kyushu, followed by an assault on the Tokyo plain (40,000 dead); 2) an attack on southern Kyushu, followed by northwestern Kyushu (25,000 dead); and, 3) an attack on southern Kyushu, followed by northwestern Kyushu, and then the Tokyo plain (46,000 dead). Barton J. Bernstein concluded,

Clearly, all these estimates fell far short—by at least 454,000—of later claims of 500,000 American lives. In fact, in early June 1945, when a layman suggested a high number as a half a million dead, army planners bluntly replied in a secret report: “[such an] estimated loss…is entirely too high.”

In private writings soon after Hiroshima and Nagasaki—and thus having little reason to exaggerate numbers—US military leaders agreed that the claim of 500,000 American lives saved was entirely too high. Not only this, but General MacArhtur believed that the casualties and deaths would not be as high as the rate at Normandy and Okinawa (65,631 casualties; 7,374 deaths), in fact, he estimated that total casualties would be well under 100,000. This was communicated to the White House by General Marshall. Even the more pessimistic Admiral Leahy—mistakenly overstating Okinawa casualty estimates for reference—suggested that the highest estimate for casualties at Kyushu would possibly be 230,000. Other estimates, based on similar historical documents, argue that “even in the worst case, [American lives saved] would have been in the range of tens of thousands rather than hundreds of thousands.”

The scholarly consensus now asserts that the war would have ended in a relatively short time even without the atomic bombs, that the alternative invasions of Japan would have been unlikely, and that Truman and his advisers were aware of these options. Another scholar, using the facts available at the time, argues the results of the unlikely worst case,

If this “worst-case scenario” had occurred—that is, if the atomic bomb had not worked or had not been used, and if Japan had somehow held out beyond November 1, 1945, and if the successful invasion of southern Kyushu had been carried out, and if the Russians had entered the war in August (as they did) and engaged the Japanese in Manchuria and Korea, and if at that point the Japanese had surrendered—then a reasonable estimate of American deaths almost surely would have been not more than 20,000 and probably less than 15,000 (5,000 for air and naval losses before the invasion, not more than 10,000 during the invasion of Kyushu, and an added allowance of 5,000 for unforeseen losses). (emphasis added)

Nevertheless, while it is difficult to backwards project a counterfactual history that did not happen, the fact remains that, “When Truman approved the order of July 24 to use atomic bombs, he had never received a high-level report suggesting half a million or even a quarter a million U.S. dead.” No US military planner between May 1945 and the period following the bombings would have put the number of American lives saved anywhere near that high. To put it succinctly, “The myth of 500,000 [let alone millions of] American lives saved thus seems to have no basis in fact.”

Joshua Mawhorter is assistant editor of Mises.org. He was a summer fellow at the Mises Institute (2023) and a government/economics and US history teacher since 2016. Josh has a bachelor’s degree in political science from California State University, Bakersfield, a master’s in political science from Southern New Hampshire University, and a master’s in Austrian economics from the Mises Graduate School.

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