The Decision to Drop the Atomic Bomb

Podcast Transcript

In August 1945, a single decision changed the course of history and introduced a weapon unlike anything the world had ever seen.

The choice to drop the atomic bomb didn’t just end World War II; it opened the nuclear age and sparked debates that continue to this day.

Was it necessary? Was it justified? And could the war have ended another way?

Learn more about the decision to use the atomic bomb, why it was made, and the consequences that still shape our world today on this episode of Everything Everywhere Daily.

The roots of the atomic bomb decision trace back to 1939, when physicists, including Albert Einstein and Leo Szilard, warned U.S. President Franklin D. Roosevelt that Nazi Germany might be developing atomic weapons.

Their letter led to the creation of what would become the Manhattan Project, a massive, secret effort to build an atomic bomb before Germany could.

From 1942 onward, the project brought together leading scientists, including J. Robert Oppenheimer, who directed the Los Alamos laboratory, and General Leslie Groves, who oversaw the military side.

The project operated under the assumption that the Axis powers, particularly Germany, were racing toward the same goal.

By 1945, Germany had surrendered, and it became clear they had not come close to building a bomb, a topic I covered in a previous episode. However, the United States now possessed a powerful new weapon, and the war with Japan continued.

By mid-1945, Japan was militarily defeated in many respects. Its navy was largely destroyed, its air force weakened, and American bombing campaigns had devastated major cities.

Yet Japan had not surrendered.

The Japanese had a samurai mentality. They were deeply committed to victory. The Japanese believed the most righteous act was to die for their emperor in battle. Surrender was not an option, even for the smallest islands.

As the US tightened the noose around Japapn it strategically chose key islands to advance toward the Japanese mainland.

Every victory took time and was costly. Each battle used up large amounts of material and resulted in many deaths. For example, the Battle of Okinawa cost over 100,000 lives between both sides in three months. The island is just under 19 square miles.

As US forces neared mainland Japan, they saw the high potential for American casualties. Japanese civilians, including women and children, were prepared to fight, and kamikaze pilots intensified the threat. Every step promised brutal resistance.

The US had also launched brutal firebombing raids on Japanese cities, especially Tokyo. Many Japanese buildings were made of wood, making them highly flammable. The firebombing of Tokyo in March 1945 alone killed an estimated 100,000 people.

The goal of the firebombing campaign was to destroy Japanese morale and force surrender. Although raids devastated cities, the Japanese refused to yield.

US leaders debated whether Japan would be defeated faster by a full invasion or by a naval blockade and bombing its infrastructure.

They decided that a full invasion was best because it was expected to be less costly for the Allies in the long run, given the belief that other strategies might prolong the war and lead to even greater losses. This became known as ‘Operation Downfall.’

The start of the invasion of the Japanese mainland was supposed to be in November of 1945, and it was hoped that the operation would be finished by Spring of the following year.

Given the Japanese mindset, the invasion of the main islands was expected to be exceptionally hard-fought, with unwavering resistance.

As intelligence gathered more information about what an invasion of the Japanese mainland would look like, the US government grew increasingly concerned. Assessments of the defensive capabilities of the Japanese saw the predicted number of American casualties potentially reaching millions.

The Americans were thrown for a loop on April 12, 1945, when President Roosevelt died and his Vice President, Harry Truman, ascended to the office.

Truman had not been deeply involved in the Manhattan Project and was only briefed on it after taking office. Soon after, Truman faced the reality of the bomb and the question of how to use it.

On July 26, 1945, the United States, Britain, and China issued the Potsdam Declaration, calling for Japan’s unconditional surrender. It warned of “prompt and utter destruction” if Japan refused.

This wasn’t just an empty threat or typical wartime saber-rattling. What the Japanese and almost no one else knew was that on July 16, the day before the opening of the Potsdam Conference, the US had conducted the Trinity Test, the world’s first detonation of an atomic bomb, a topic I covered in a previous episode.

Truman himself was notified of the test while he was attending the Potsdam Conference.

Needless to say, Japan did not accept the Potsdam Declaration. Its leadership was divided, with some seeking a conditional surrender, especially to preserve the emperor, and others determined to fight on to the bitter end.

Within the U.S. government and scientific community, there was debate over how or whether to use the bomb.

Some scientists, including members of the Franck Committee, argued for a demonstration of the bomb on an uninhabited or underpopulated area to encourage surrender without mass civilian casualties.

They first considered targets such as Tokyo Bay or a military installation, which would result in fewer deaths. The bomb could serve as a demonstration of power rather than just a military attack.

Others, including military leaders and policymakers, believed that only direct use against Japanese cities would produce the shock necessary to end the war quickly. There were also concerns that a demonstration might fail, undermining its psychological impact.

Truman ultimately accepted the recommendation to use the bomb without prior demonstration. The motivation was to select targets that would leave no doubt about the bomb’s destructive capability and prompt a quick Japanese surrender.

It should be noted that Truman largely accepted the recommendations placed in front of him. In that sense, the military and his advisors shaped the options, and Truman chose among them as he hadn’t been looped in on the atom bomb program while he was Vice-President.

There were two ultimate goals of using the atomic bombs: the first was to intimidate the Japanese into unconditionally surrendering, and the second was to show the world the power of their new weapon, specifically the Soviet Union.

Hiroshima was chosen as the location where the first bomb would be dropped. The city was compact and surrounded by hills. This made it easy to assess the bomb’s damage. Hiroshima had been mostly untouched by earlier campaigns, serving as a military and urban hub.

The first bomb was dropped at 8:15 in the morning on August 6, 1945. The bomb, “Little Boy,” was dropped 1,800 feet above the city. The blast delivered the force of roughly 12.5 kilotons of TNT.

“Little Boy” was a gun-type fission bomb that used highly enriched uranium, firing one piece of uranium into another to trigger a nuclear chain reaction. It was a simple design that required relatively simple engineering.

The bomb decimated five square miles of the central city. In the first four days, an estimated 120,000 people died. Some were instantly vaporized, and others died from burns and radiation.

After the dropping of the bomb on Hiroshima, the Japanese still refused to surrender. The Japanese military leadership did not think that the US had more atomic weapons. The shock of one bomb was not enough to dissuade military leadership from the glory of one final, decisive battle.

On August 8, 1945, the Soviet Union finally declared war on Japan and invaded Japanese-held territory in Manchuria. This fulfilled earlier Allied agreements and shocked Japanese leadership, which had hoped to use the Soviets as mediators with the Americans.

The next day, August 9, another bomb was dropped on the city of Nagasaki. The bomb, called “Fat Man,” was an implosion-type fission bomb that used plutonium, employing precisely timed explosives to compress a plutonium core into criticality; unlike Little Boy’s simpler gun-type uranium design, it was far more complex and efficient.

Nagasaki was actually not the initial target of the second bomb. The main target was the city of Kokura, chosen for its military and industrial importance. It was one of the largest weapons depots and a major manufacturer of armaments.

Fortunately for Kokura, on the day of the bombing, the city was obscured by clouds and smoke. This meant that the bomber had to change locations to its secondary target, Nagasaki.

Nagasaki supported the Japanese war effort through munitions manufacturing and shipbuilding. Like Hiroshima, Nagasaki had not faced significant damage from the previous bombing campaigns, making it a good strategic and visual target.

Though the plutonium bomb was more powerful than the one dropped on Hiroshima, “Fat Man” actually caused less destruction to Nagasaki. This is because Nagasaki’s terrain is flatter, making it slightly less deadly.

Regardless, the bomb’s impact was still massive, killing approximately 73,000 people. A two-square-mile radius around the bomb epicenter was completely annihilated.

The Americans were now concerned because after the bomb was dropped on Nagasaki, they didn’t have any completed atomic bombs in their arsanel. They had used both of the bombs that they had made.

After Nagasaki, U.S. military planners were preparing to deliver another bomb as soon as it became available, which was expected around August 17 or 18. This became known as the “third shot.”

General Leslie Groves indicated that more bombs would follow in sequence as they were completed. The intention was not a one-time demonstration, but a continuing campaign of atomic strikes if necessary.

Thankfully, dropping the second bomb succeeded in forcing the Japanese surrender. They unconditionally surrendered on August 14, 1945, though the official documents of surrender were not signed until September 2.

By the end of 1945, close to two hundred thousand of people were killed by atomic weapons. Those who survived the bombing faced lasting impacts, including the development of cancers like leukemia, and negative side effects from the radiation.

Ever since the decision was made, debates have raged as to whether or not it was the right choice to drop the atomic bombs.

Those who defend the decision to drop the bomb often argue that it was a necessary choice to avert the enormous casualties predicted for an invasion of the Japanese mainland, potentially saving hundreds of thousands, if not millions, of lives. Furthermore, the action swiftly concluded the war and served to demonstrate the United States’ military power to future adversaries.

Opponents of the decision frequently assert its immorality, arguing that the bombing of a largely civilian population constituted a profoundly immoral act.

Some believe Japan was nearing surrender because the Soviet invasion of Manchuria had already placed the nation under siege from all sides. Other say the alternatives proposed at the time, included demonstrating the weapon in an uninhabited area, could have been pursued.

As for Truman, he never publicly expressed any regret for the decision to drop the atomic bombs, and for the rest of his life, he consistently defended it.

In the immediate aftermath of the bombings of Hiroshima and Nagasaki, Truman framed the decision as a military necessity to end the war quickly and avoid the enormous casualties expected from an invasion of Japan.

In his memoirs and later interviews, he repeatedly stated that using the bomb saved hundreds of thousands of American lives, and likely many Japanese lives as well.

That said, his private language was sometimes more complicated. He referred to the bomb as a “terrible” weapon and expressed discomfort with its destructive power.

Dropping the atomic bomb did more than just conclude a war; it ushered humanity into a new, precarious era where the power of self-destruction suddenly became a reality.

It was a decision shaped by fear, urgency, imperfect information, and the brutal logic of total war. Whether viewed as a necessary act or a moral tragedy, it remains one of the most consequential decisions ever made in human history.

The Executive Producer of Everything Everywhere Daily is Charles Daniel. The Associate Producers are Austin Oetken and Cameron Kieffer.

Research and writing for this episode were provided by Olivia Ashe.

Today’s review comes from Jim Ketchum on Facebook, who writes.

I started listening to this amazing podcast about a year and a half ago. I keep hearing about this great club called The Completionist Club. Looking at the number of episodes, I said there’s no way I would make it. Today, I am officially a member of the Louisiana Completions Club.

Gary, please send me the door code for the clubhouse, and I will get a pot of gumbo and some jambalaya started for the party. Thanks for a great show, and I’m looking forward to hearing them all again.

Thanks, Jim! The code for the clubhouse is for members only, so please do not share it. It is 1-2-3-4-5.

I guess now that I say it out loud we should have probably changed it after we got it installed.

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