Why Truman Dropped the Bomb: The Role of Uncertainty
By Micah J. Loudermilk
Last week, in marking the 67th anniversary of Hiroshima and Nagasaki, Nathan Donohue authored a thoughtful summary analysis of President Truman’s decision to use the world’s first atomic weapons against Japan. Although his article, published on this forum, offers a number of reasons why Truman opted to drop the bombs, the bulk of the piece looks at alternative options the United States possessed for ending the war. These options and considerations – on both sides of the debate – have been endlessly scrutinized over the years and Mr. Donohue’s article accurately reflects that debate. That being said, across over 50 years of academic study and work on one of the 20th century’s most far-reaching decisions, many analyses and discussions often ignore – or inadequately address – arguably the most compelling reason why Truman authorized using the bombs: uncertainty.
Returning to Mr. Donohue’s commentary, an extensive list of variables exist that scholars have used as lenses through which to study Truman’s decision. However, regardless of which side one ultimately falls on – either for or against using the bombs – uncertainty remains a pervasive element.
To begin with, the casualty count for a potential invasion of Japan is a rallying point for both sides of the debate – with estimates ranging from 31,000 casualties to upwards of one million. The math leading to these numbers though was largely reliant on assumptions about the size of Japan’s army on the home islands – about which intelligence was limited at best. Additionally, other factors had to be weighed including potential resistance from the civilian population and the fact that Japan’s military leaders would have no incentive to hold back any part of their remaining capabilities. Trying to assess casualty rates as a fixed percentage of total invasion forces based on the US experience in Okinawa (35 percent) as Admiral William Leahy did proved no more successful. Indeed, the Joint Chiefs of Staff wrote in the summer of 1945 that “Our experience in the Pacific War is so diverse as to casualties that it is considered wrong to give any estimate in numbers.”
Numerous other variables also reflected this uncertainty:
How close was Japan to capitulation prior to Hiroshima and Nagasaki? Months of conventional and strategic bombing of the Japanese islands – far more destructive in both property and human life than the atomic bombs – proved completely unsuccessful in generating the desired surrender.
Would a full naval blockade of the home islands have achieved Japanese capitulation? Many like to argue that it would have, and in a relatively short time period, but a relentless American policy of “island-hopping” across the Pacific, resulting in an ever-growing naval stranglehold, had failed to achieve that result. Even had it been successful though, how long would it have taken, and at what cost?
What about the Soviet Union? Although allies during World War II, American policymakers were already well-aware that postwar tensions with the Soviets were going to boil over when the war ended. Stalin’s entry into the Pacific theater could have led to a Japan divided in much the same way as Germany, with uncertain results. Besides this, it is highly possible that a Soviet invasion would have led to more Japanese casualties than were caused by the atomic bombs.
It is equally important to approach this issue from the perspective of decision-makers in 1945 – not scholars and academics in subsequent years. Some of the uncertainty on the questions outlined above may have been cleared away in the years since World War II ended, but, it is patently unfair to examine Truman’s decision using criteria and information that was not available at the time. Even factoring in decades of work on the subject – the verdict is still inconclusive.
Policymakers operate in a world of limited time, resources, and information and they must often work without the luxury of extended scrutiny and analysis. Uncertainty is akin to the proverbial “fog of war” and Truman was certainly not immune. Embroiled in the bloodiest and most destructive conflict in human history, Truman and US military leaders opted to follow the clearest path possible towards ending the war. Ultimately, it is a mistake to judge Truman’s decision without realistic acknowledgement of the context in which it was made.
Micah J. Loudermilk is the Senior Research Associate for the Energy & Environmental Security Policy Program with the Institute for National Strategic Studies at National Defense University, contracted through ASE, Inc.
The opinions expressed in this article are those of the author alone and do not necessarily represent those of the Center for Strategic and International Studies, the Project on Nuclear Issues, the National Defense University, the Department of Defense or the U.S. Government.