The following article appeared on August 6, 2000 in the St. Petersburg Times newspaper and was written by Peter D. Zimmerman. Mr. Zimmerman writes frequently on arms control and national security issues.

A-bomb attack on Japan was necessary

By late July 1945, Japan was strategically defeated. The Imperial Navy would never again sail to threaten U.S. ships; the Greater East Asia Co-prosperity Sphere had shrunk to a small oval enclosing the Home Islands, Korea and parts of China.

Japan's ultimate defeat was certain. Never the less, it still retained significant capability to wage war and to wreak havoc on the populations and prisoners of war remaining under its control. Waiting for Japan to implode and risking the death throes of the defeated enemy was not an option.

On the 50th University of the bombings of Hiroshima and Nagasaki, many historians debated the necessity of the atomic bombings. Japan, they suggested, could never have held out. If an invasion had been necessary, the Japanese would not have been formidable adversaries, and in any event, if the allies had merely offered to allow Emperor Hirohito to remain on his throne, Japan would have surrendered.

I thought differently then, and, five years later with then help of a newly released CIA intelligence report I am even more thoroughly convinced.

It was imperative to end the Pacific war as soon as possible. American POW' were suffering appallingly; the civilian captives in Singapore and Hong Kong were in desperate straits. It seemed at least probable that many of them would be murdered within weeks as their captors sought to divert food and troops from the camps to military uses. Finally, the end of the war would mean an end to both American and Japanese casualties. The lessons of Okinawa and Iwo Jima remained fresh.

In the last five years, answers have emerged to the critical question surrounding the decision to drop the A-bomb: "What did President Truman know about the Japanese strength and when did he learn it?" President Truman knew a great deal, and none of it pointed to a speedy end of the conflict without the bomb or a battle for the Japanese homeland at awful cost. One hundred thousand Japanese defenders on Okinawa cost 48,000 US casualties, half the Japanese on Iwo Jima died.

A year ago the CIAs Center for the Study of Intelligence released intelligence reports gathered in the final months of the war, new information that should decisively shut the debate.

A note in Truman's own handwriting says that Gen. George C. Marshall's estimate of US casualties was about a quarter-million killed, wounded and missing. The actual estimate by the Joint War Plans Committee was 220,000 as of early June-close enough. However, we now know that this figure was based on a near-catastrophic underestimate of Japanese troop strength.

In May, US Intelligence estimated that Kyushu was the base for 246,000 Japanese, of whom 128,000 were in Army ground force units. Projecting forward to Nov. 1, the scheduled date for Operation Olympic, military analysts estimated that Japan could reinforce the island with 100,000 more soldiers for a total of about 350,000 troops.

But by June 16, Kyushu was already home to more Japanese divisions than had been considered the maximum number possible in November. In mid-July, US Intelligence turned up three more divisions on the island`, and by the end of the month yet another appeared, bringing the total to 12, including 10 combat divisions.

A week later, on August12, Japanese strength on Kyushu had soared to 579,000. General Charles Willoughby, Mac Arthur's intelligence chief, said of Japanese reinforcements, "the end is not in sight." Since the planned invasion force numbered 770,000 including the crews of the naval vessels supporting the landing, Willoughby suggested that the Americans and Japanese armies might have equal strength-not he said, "A recipe for victory."

Two days before Hiroshima, Japanese forces in Kyushu reached 600,000. Nine divisions faced the invasion beaches in the south, three times the force projected when Operation Olympic was planned. President Truman may not have known the final figures when he released the atomic weapons to the Air Force, but he and his closest advisors knew the magnitude of the forces arrayed against us.

The ability to move 360,000 troops to Kyushu between May and August demonstrated that Japan retained both the will and the ability to continue the war for months to come. Not only was the force in place but also so were the logistics and supplies to sustain it in the field against and invading army.

The cost of an invasion to both sides would have been horrendous. Japanese troops on Iwo Jima and Okinawa died rather than surrender; who can doubt that the defense of Japan itself would have been equally ferocious?

We may never know if a continuation of conventional bombing and the naval blockade of Japanese ports would have brought capitulation without invasion. Perhaps it would have, but many Japanese lives would have been lost in the bombing. And the postwar world have been very different. The Soviet Army invaded Korea on Aug. 7 and in a few weeks might conquered enough territory to demand a place at the peace table. Even after Japan surrendered, Stalin demanded partition of the country at the same 38th parallel that split Korea; with his troops on the ground it would have been impossible to say "no."

The destruction of Hiroshima and Nagasaki served three purposes: it terminated the conflict instantly, saving American lives, it insured a united Japan rather than leaving half of the country to the same fate as North Korea; and perhaps it provided an example which has deterred the use of nuclear arms for 55 years.

All writers on this subject have biases, and all view the end of the war through spectacles they have worn for many years. It is only fair to state my own: My father was a US Naval officer in command of a Seabee unit slated for Operation Olympic. He didn't have to go.

But the objective evidence now available demonstrates simply that the sacrifice of Hiroshima (from where Admiral Yamamoto on his flagship Nagato commanded the attack on Pearl harbor), and of Nagasaki as well, was preferable to the likely alternatives.

NOTE BY Jim Meeks who sent me this article: I agree with all of the above except where in the third paragraph from the end, Mr. Zimmerman states, " It terminated the conflict instantly, ----". Records show that there were conventional bombing missions after the Nagasaki bomb was dropped.


Atomic weapons have been used only twice. Fifty-five years ago August 6 the USA exploded the firs atomic bomb over Hiroshima, Japan, killing more than 130,000 people. Three days later on August 9, 1945, a second American atomic strike hit Nagasaki. On august 14, Japan surrendered ending WWII. For more than half a century, the debate has continued over the use of atomic weapons to defeat the Japanese without a more costly invasion.

What do you know about the development of our atomic weapons. Take the quiz.

1. What physicist's letter to President Roosevelt set in motion America's wartime program to develop an A-bomb?

2. What was the top-secret program's code name?

3. Who was its director?

4. The untested uranium bomb dropped on Hiroshima nicknamed Little Boy, was released by what aircraft?

5. What was different about the bomb dropped on Nagasaki?

CLICK HERE for answers!