Alex Wellerstein on the Atomic Bomb Decision, Truman’s Accountability, and the Nuclear Taboo

Nuclear historian Alex Wellerstein presents a revisionist account of Harry Truman and the atomic bombings of Hiroshima and Nagasaki: Truman did not order the bombs dropped in any conventional sense, may have genuinely misunderstood the nature of the targets, and — partly because of that experience — became the foremost advocate for a nuclear taboo that has arguably prevented their use ever since.

Key ideas

1. Truman did not order the atomic bombings. The decision was never formally deliberated; the military was already running an assembly-line targeting programme inherited from the Roosevelt administration. Truman was kept broadly in the loop but was not asked to make a choice. He inherited a machine already in motion.

2. Truman misunderstood what he was approving. The only substantive targeting discussion Truman took part in was whether to spare Kyoto. Secretary of War Henry Stimson argued for removing Kyoto on the grounds that it was a cultural, civilian city distinct from a military installation like Hiroshima. Truman appears to have come away believing he had approved strikes on ‘purely military targets’ — not on cities containing women and children — which explains the lifelong contradiction between his private horror at civilian casualties and his public ownership of the decision.

3. The Kyoto exemption made Hiroshima number one. General Leslie Groves repeatedly lobbied to restore Kyoto to the target list; Stimson escalated to Truman at Potsdam to get a definitive no. That ruling removed Kyoto, elevated Hiroshima, and added Nagasaki as the backup — without Truman apparently grasping the chain of consequence.

4. Truman almost certainly did not know a second bomb was coming. By the time Stimson showed Truman damage photographs confirming Hiroshima was a city, the Nagasaki mission was already airborne. On 10 August 1945 Truman ordered the atomic bombings halted, citing his unwillingness to kill more children — the clearest sign he felt he had lost control of something he thought he commanded.

5. Truman centralised nuclear authority to prevent future use, not to enable it. Starting the day after Nagasaki, Truman made presidential exclusivity over nuclear release the operating principle — not because the Constitution required it, but because he did not trust the military. Wellerstein argues this distrust, shaped by his own experience of being bypassed, is the origin of the nuclear taboo: the first American president to possess these weapons was also their most committed opponent.

Content

The orthodox story and what it misses

Two standard narratives dominate public understanding of Hiroshima. The first — the official version, enshrined in Truman’s own memoirs — is that he weighed the anticipated casualties from a land invasion against the deaths from the bomb and chose the lesser evil. The second, revisionist version holds that the bombs were dropped primarily to intimidate the Soviet Union rather than to end the war. Wellerstein rejects both. Neither story, he argues, matches what the sources actually show: a president who was not invited to deliberate at all, who was absorbing fire-hose volumes of new information after barely a hundred days in office, and who walked into a targeting process already set in motion by the military under Roosevelt.

The more radical and precisely documented claim is that Truman was kept in the dark not through deliberate deception but through institutional incoherence. The Manhattan Project had been Roosevelt’s personal secret; FDR died before briefing his vice president. Stimson’s April 1945 briefing of Truman — covering the entire history and science of the Manhattan Project — took twenty-five minutes. Truman, an artillery officer from the First World War with no background in physics, was then expected to govern civilisational decisions about weapons he barely understood.

The Kyoto conversation and the fatal misunderstanding

The episode centres on a single meeting between Truman and Stimson at Potsdam. Stimson had already fought Groves repeatedly to keep Kyoto off the target list; now he needed the president’s backing to make the removal stick. Stimson’s diary records a rational case about historic and civilian character; Truman’s journal records an agreement not to bomb women and children, and the choice of a ‘purely military target’. The two men appear to have had the same meeting and left it with different understandings of what had been decided.

Wellerstein does not attribute this to bad faith on Stimson’s part. Stimson was trying to save Kyoto, and he used whatever framing would work. The distinction he drew — Kyoto as civilian city, Hiroshima as military installation — was not wholly wrong, but it was not wholly right either: Hiroshima had a substantial civilian population. Truman, busy negotiating with Stalin, apparently did not press for clarification. The misunderstanding hardened into the stated policy — ‘purely military targets’ — and only collapsed when the photographs arrived on 8 August 1945.

After the bomb: the taboo is born

Truman’s response to learning what had actually happened to Hiroshima was not public recrimination but private anguish and political action. He stopped the atomic bombings after Nagasaki. He began centralising launch authority in himself — a posture with no formal constitutional basis at the time and not reduced to official policy until 1948. He repeated throughout his presidency, against the expectations of his advisers and the military, that nuclear weapons must never be used again.

Wellerstein traces the consequence forward. Under Eisenhower, military custody of the stockpile expanded dramatically and the weapons were pre-delegated to commanders in ways that horrified Kennedy when he entered office. The Cuban Missile Crisis made visible how many pathways to nuclear war existed outside any president’s direct control. But the Truman presidency had already seeded something: the idea that nuclear weapons are not ordinary weapons, that their use crosses a moral threshold ordinary warfare does not. The military in the 1950s was explicitly alarmed by this taboo and could name its principal advocate: the president. Wellerstein’s argument is that the irony of Truman’s legacy is total — the only president to use nuclear weapons in war may be the central figure in why they have not been used since.

The individual in the system

The episode ends on a methodological point that reaches beyond Truman. Wellerstein resists pure structuralism — the view that historical forces determine outcomes regardless of who holds power. If the nuclear command had been decentralised in 1950, MacArthur in Korea would likely have had authority to use tactical nuclear weapons; the contingency chain in the Cuban Missile Crisis might have resolved differently. The accident of Truman — an ‘everyman’ figure, morally uncomfortable with mass civilian killing, distrustful of the military — in precisely that position at precisely that moment may have been, Wellerstein suggests, decisive. The system matters. But sometimes so does the person at the top of it.

Related

• Alex Wellerstein — guest; author of The Most Awful Responsibility
• Dan Carlin — host
• Deciding Under Uncertainty — Truman’s position as an archetype of incomplete information and high-stakes improvisation