Harry S. Truman had been president for five days when on 17 April 1945, he walked into his predecessor’s White House Map Room for the first time. Written on a map of the Pacific were many notes, including “Invade Jap Homeland Fall of 1945.”1 At the time, Truman, simultaneously learning about the war and trying to run it, was focusing on Europe. But on 7 May Germany surrendered and his strategists could concentrate on defeating Japan.
President Truman was now commander-in-chief of a one-front war that seemed destined to end in a massive invasion of Japan that would dwarf the D-Day landings in Europe. But both General Henry H. “Hap” Arnold, chief of the Army Air Forces, and Fleet Admiral Ernest J. King, U.S. Fleet commander-in-chief, believed there was another way: force Japan to surrender by launching a relentless heavy bombing campaign and a naval blockade. Early in 1945, Arnold had pressured Brigadier General Curtis E. LeMay to improve the performance of the B-29 Superfortresses bombing Japan by raising the specter of invasion. LeMay translated the warning as, “If you don’t get results, it eventually will mean a mass amphibious invasion of Japan, to cost probably half a million more American lives.”2
That became one of the horrendous casualty numbers introduced into strategic planning for the end of the war. The Arnold-King bomb-and-blockade alternative would prolong the war—probably until the middle or latter part of 1946, according to an intelligence estimate submitted to the Joint Chiefs of Staff. But that choice would not generate high American casualties.3
The atomic bomb might be yet another way to end the war, but the first such weapon would not be ready for testing until July, with slow production after that—if it worked. Moreover, this alternative produced a question that still is asked 70 years later: How many American lives would be saved by its use? In other words, how many U.S. servicemen would die if President Truman decided to end the war with an invasion instead of the atomic bomb?
Truman and his planners decided to use the invasion and conquest of Okinawa as a casualty gauge, comparing the ferocity of Japanese resistance on that island to what could be expected if Japanese soldiers and millions of civilians fought for Emperor Hirohito in a final defense of their homeland. The grueling April to June 1945 Battle of Okinawa cost the lives of 12,638 U.S. soldiers, Marines, sailors, and airmen; 36,631 others were wounded. The Okinawa casualty figures could foreshadow only the cost of the first phase of the invasion, the storming of Kyushu. In the spring of 1946 was to come the final assault: the invasion of the island of Honshu and the taking of Tokyo, which was expected to be far more costly than the battle for Kyushu.
Canvassing for Estimates
On 14 June, Fleet Admiral William D. Leahy, Truman’s chief of staff, sent a memo to the Joint Chiefs that the president wanted a meeting to
discuss details of our campaign against Japan [including] an estimate of the losses in killed and wounded that will result from an invasion of Japan proper [and] an estimate of the time and the losses that will result from an effort to defeat Japan by isolation, blockade, and bombardment. . . . It is his intention to make his decision on the campaign with the purpose of economizing to the maximum extent possible in the loss of American lives.4
The Joint Chiefs moved swiftly to prepare a briefing for the president. Major General John E. Hull, chief of the Army’s Operations Division, went to the heart of what Truman wanted. “The President is very much perturbed over the losses on Okinawa,” he told Brigadier General George Lincoln, chief planner to General of the Army George C. Marshall, the Army chief of staff. Hull suggested that Lincoln give Marshall all of the casualty information he could find, not only from Okinawa but also from Iwo Jima, Leyte, Luzon, and “overall figures on MacArthur’s operations to date.”5
A priority message went out on 16 June from Marshall to General of the Army Douglas MacArthur requesting “the estimate you are using for planning purposes of battle casualties.” MacArthur already had been given “primary responsibility” for the invasion of Japan. The operation, code-named Downfall, had two main components: Olympic, scheduled for November 1945, and Coronet, for March 1946. The first would be the invasion of Kyushu, the southernmost of Japan’s four main islands. American forces would storm three beaches to take and hold the southern part of the 16,205-square-mile island, where air bases were to be built for warplanes that would bomb Honshu, the principal Japanese island. The second operation would be the invasion of Honshu and include the assault on Tokyo.
MacArthur promptly sent an estimate of 50,800 U.S. losses—dead, wounded, and missing—for the first 30 days of the Kyushu invasion. Unsatisfied, Marshall sent another message to MacArthur, noting that Truman was “very much concerned as to the number of casualties” for the entire operation on Kyushu. The Army’s senior commander in the Pacific apparently only then appreciated the extreme importance that the casualty rates would play in Truman’s decision whether or not to invade. In a long reply that did not include a new number, MacArthur backpedaled, saying the estimate had been “a routine report” that “had not come to my prior attention.” He added, “I do not anticipate such a high rate of loss.”6
Two other documents pertaining to casualty estimates were prepared for Truman. One put U.S. losses for the two operations as high as 220,000; the other said casualties would be closer to those suffered in the invasion of Luzon: 31,000.7
The unending controversy over U.S. casualty estimates had begun. The Army—and especially MacArthur—wanted an invasion and therefore favored low estimates. High estimates made invasion a far less attractive alternative over the potential use of the atomic bomb. Mindful of the heavy toll kamikazes had taken on their ships at Leyte and Okinawa, Navy leaders tended toward pessimistic invasion-casualty forecasts.
On 16 June an all-civilian science committee headed by Secretary of War Henry L. Stimson considered a proposal to demonstrate the atomic bomb—an idea that would persistently appear in postwar debates. The panel concluded that such a trial was totally impractical, saying, “we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use.”8 For both military and political reasons an attempt to demonstrate an atomic bomb for Japanese scientific or military officials was completely unrealistic.
A Decision is Reached
On the afternoon of 18 June President Truman presided over a top-level strategy session about ending the war. Estimates of casualty counts dominated the meeting.9 Admiral King said he believed that “a realistic casualty figure for Kyushu would lie somewhere between the number experienced by General MacArthur in the operations on Luzon and the Okinawa casualties.” Leahy had mentioned the premature Okinawa casualty rate of 35 percent, apparently inspiring a remark from Truman. As the official record put it: “THE PRESIDENT expressed the view that it [the invasion] was practically creating another Okinawa closer to Japan, to which the Chiefs of Staff agreed. . . . He had hoped that there was a possibility of preventing an Okinawa from one end of Japan to the other.”
General Marshall said that Japan’s navy, “if any still exists, will be completely powerless.” But Japanese submarines were still going to sea and the country’s shipyards were producing more of the craft, including hundreds of Koryu midget submarines, capable of carrying torpedoes or being armed with explosives for suicide attacks, and hundreds of manned torpedoes launched from submarines. The imperial navy also was training men to serve as human mines—known as Fukuryu (hiders). Clad in a diving suit, breathing from oxygen tanks, and armed with a mine mounted on a pole, a Fukuryu was to sink an approaching landing craft with his weapon, killing himself in the process. The navy hoped to have 4,000 men trained and equipped for this underwater attack force before the invasion began.10
Suicide weapons were expected to inflict massive casualties on U.S. forces before the first soldiers and Marines hit the beaches. The American troops then would encounter a million-man-plus Japanese army and hordes of civilians—the latter armed with some rifles, pointed sticks, and explosive charges.
As Truman met with his strategists, Major Eizo Hori, an intelligence officer on the Japanese Imperial General Staff, was producing such accurate forecasts of the landings that fellow officers called him “MacArthur’s staff officer.” Hori picked Kyushu as the likely invasion site and late October as the probable date.11 U.S. intelligence, based on intercepted and decrypted Japanese message traffic, discovered that the waters off the three proposed invasion beaches had already been mined and coastal civilians had been partially evacuated.12 Nevertheless, near the end of the 18 June strategy session, Truman announced his decision: U.S. forces would invade Kyushu on 1 November.
The president had a third alternative: negotiate an end of the war. The suggestion had come in a long memo from former President Herbert Hoover, who said he believed he had a way to save “the lives of 500,000 to 1,000,000 American boys”—an estimate for which he did not give a source.13 Hoover’s memo, circulated among Joint Chief planners as a top secret paper, was dismissed. But this incredible estimate would endure to haunt the continuing debate over the casualty cost of invasion versus Truman’s decision to drop the atomic bomb.
Use of and Fallout from the Bombs
When Truman learned that an atomic bomb had been successfully tested on 16 July, he ordered that the weapon be used. During a meeting of the president and his principal advisers about six days later, Truman asked General Marshall what an invasion of Japan would cost in U.S. lives. His reply—250,000 to 1 million—added to the president’s growing conviction to use the bomb.
Three atomic bombs would be available in August. A Superfortress dropped one on Hiroshima on 6 August. Informing the American public of the news that same day, the president said that if Japan did not now accept U.S. surrender terms it “may expect a rain of ruin from the air the like of which has never been seen on this earth.” When no reaction was forthcoming from the Japanese government, a second bomb was dropped on Nagasaki on 9 August. The third would be ready shortly.
Even with Hiroshima and Nagasaki destroyed, the military officers ruling Japan were still planning what they called the Decisive Battle—a bloodbath that would produce so many Americans casualties that Truman would have to open negotiations. U.S. intercepts of secret Japanese military and diplomatic communications revealed that the ultimate Japanese demands would be: the retention of Emperor Hirohito as ruler; a limited, if any, Allied occupation; the right of Japanese troops to surrender their weapons to Japanese officers; Japan’s retention of some areas of the Asian mainland occupied by Japanese troops; and the acknowledgement that any trials of Japanese war criminals would be held in Japanese courts.14
Emperor Hirohito knew that such demands were fantasies. In an emotional address to his subjects, he overruled the military government and declared the end of the war—without uttering the word “surrender.”
Some postwar historians have challenged President Truman’s decision to use the atomic bomb to shorten the war and save American lives. They claim that the Allies could have ended the war by coming to terms with the Japanese, but, in retrospect, negotiating an end to the conflict based on realistic surrender terms was impossible because of the hardliners in control of Toyko’s government. Still others have called the dropping of the bombs a cynical demonstration of U.S. power—making Hiroshima and Nagasaki not so much the last targets of World War II but rather the first targets of the Cold War. One historian even accused Truman of deliberately concocting a “myth” about the ending of the war.15
The bomb-or-invade debate lives on, along with the question of how many lives were saved by the two bombs that took more than 200,000 Japanese lives.16 But other grim statistics deserve consideration. The Army’s Philadelphia Quartermaster Depot—which procured everything from combat boots to medals—ordered more than 370,000 Purple Hearts for award to wounded soldiers and the families of those expected to be killed in the final battle for Japan. The U.S. Sixth Army’s medical staff on Luzon began tabulating the amount of plasma, bandages, litters, and other medical stores that would needed for the Kyushu assault. The staff estimated that there would be 394,000 American casualties—dead, wounded, and missing—just to capture the southern half of Kyushu. The assault on Honshu and the drive to Tokyo probably could be expected at least double that number. The Army medical staff did not calculate or qualify such numbers for political reasons; they had to know how many men they would try to save.17
As startling as those figures are, they don’t include the expected casualties on board the hundreds of Navy warships, amphibious ships, and landing ships and craft needed to achieve the final victory in the Pacific in the face of kamikaze aircraft, human torpedoes, midget submarines, mines, and suicidal underwater attackers.
1. Thomas B. Allen and Norman Polmar, Code-Name Downfall: The Secret Plan to Invade Japan—and Why Truman Dropped the Bomb (New York: Simon & Schuster, 1995), 122–23, 313.
2. GEN Curtis E. LeMay, USAF, with MacKinlay Kantor, Mission with LeMay (Garden City, NY: Doubleday, 1965), 347.
3. Joint Intelligence Committee report, JIC 268/1, “Unconditional Surrender of Japan,” 25 April 1945, National Archives and Records Administration, College Park, MD (hereafter NARA).
4. “Memorandum for the Joint Chiefs of Staff” from Admiral Leahy, enclosure to JPS 697/D, 14 June 1945, Records of the War Department General and Special Staffs, NARA.
5. Hull-Lincoln correspondence: Memo, Hull to Lincoln, 16 June 1945, George C. Marshall Research Library, Lexington, VA, as cited by John Ray Skates, The Invasion of Japan (Columbia: University of South Carolina Press, 1994), 80.
6. Marshall-MacArthur messages: Marshall to MacArthur, 16 June 1945. WD 1050, MacArthur Memorial Archives, Norfolk, VA. MacArthur to Marshall: (Personal) C-19848, 19 June 1945, WD 1057, ibid.
7. Memorandum for the President, Subject: Campaign against Japan, B8, Joint War Planning Committee, 15 June 1945. Douglas J. MacEachin, The Final Months of the War with Japan: Signals Intelligence, U.S. Invasion Planning, and the A-Bomb Decision (Washington, DC: Center for the Study of Intelligence, 1998), Document 9; J.C.S. 1388/2: Microfilm, Combined Army Research Library, Fort Leavenworth, Kansas.
8. Martin J. Sherwin, A World Destroyed (New York: Alfred A. Knopf, 1975), 304–5.
9. For the official report on the meeting, see www.trumanlibrary.org/whistlestop/study collections/bomb/large/documents/pdfs/21.pdf.
10. Dorr Carpenter and Norman Polmar, Submarines of the Imperial Japanese Navy (Annapolis, MD: Naval Institute Press, 1986), 49–52, 135–36. Charles A. Barton, “Underwater Guerrillas,” U.S. Naval Institute Proceedings, vol. 109, no. 8, (August 1983), 47.
11. Hori: Alvin D. Coox, “Japanese Military Intelligence in the Pacific Theater: Its Non-Revolutionary Nature,” The Intelligence Revolution, Proceedings of the 13th Military History Symposium, U.S. Air Force Academy, October 1988.
12. See map of “Mined Areas Disclosed in Intercepted Message of 7 April 1945,” Figure 1, MacEachin, The Final Months of the War with Japan.
13. Memorandum on Ending the Japanese War, www.trumanlibrary.org/hoover/exile.htm.
14. “Magic”—Diplomatic Summary, No. 1214, http://nsarchive.gwu.edu/NSAEBB/NSAEBB162/40.pdf.
15. Barton J. Bernstein, “Reconsidering Truman’s claim of ‘half a million American lives’ saved by the atomic bomb: The construction and deconstruction of a myth,” Journal of Strategic Studies, vol. 22, no. 1 (1999), 54–95.
16. Allen and Polmar, Code-Name Downfall, 270, 274.
17. Purple Hearts: LT David L. Riley, USN, Uncommon Valor: Decorations, Badges and Service Medals of the U.S. Navy and Marine Corps (Statesboro, GA: Eagle Print Shop,1980). Luzon estimate: “Medical Service in the Asiatic and Pacific Theaters,” unpublished ms, chap. 15, 18, Center of Military History, Washington, DC.
The Terrible Civilian Toll
On 10 August 1945, the day after an atomic bomb destroyed Nagasaki, Secretary of Commerce Henry A. Wallace wrote in his diary: “Truman said he had given orders to stop atomic bombing. He said the thought of wiping out another 100,000 people was too horrible. He didn’t like the idea of killing, as he said, ‘all those kids.’”1
President Harry S. Truman never made a statement like that publicly. But another diary entry, three year later, does indicate his concern about the lethal legacy of the wartime bombs. On 21 July 1948, David E. Lilienthal, then the first chairman of the Atomic Energy Commission, quoted the president’s words at a meeting that day. In the diary, Lilienthal’s own thoughts are in parentheses:
I don’t think we ought to use this thing [the atomic bomb] unless we absolutely have to. It is a terrible thing to order the use of something that (here he looked down at his desk, rather reflectively) that is so terribly destructive, destructive beyond anything we have ever had. You have got to understand that this isn’t a military weapon. (I shall never forget this particular expression). It is used to wipe out women and children and unarmed people, and not for military uses.2
—Thomas B. Allen
1. John Blum, ed., The Price of Vision: The Diary of Henry A. Wallace, 1942–1946 (Boston: Houghton Mifflin, 1973), 473–74.
2. David Lilienthal, The Journals of David E. Lilienthal, vol. 2, The Atomic Energy Years 1945–1950 (New York: Harper & Row, 1964), 391.