Dropping of the Atomic Bomb on Japan – Comprehensive Study Notes

Present-Day Nuclear Landscape

• Color coding described on the opening world map:
  • Blue = NPT-designated nuclear-weapon states (signed the Nuclear Non-Proliferation Treaty): $\text{United States} \rightarrow \text{Russia} \rightarrow \text{United Kingdom} \rightarrow \text{France} \rightarrow \text{China}$ (chronological order of first successful test)
  • Red = Non-NPT nuclear states: $\text{India},\;\text{Pakistan},\;\text{North Korea}$ (North Korea originally signed, withdrew $02/2003$)
  • Yellow = Presumed but unacknowledged nuclear state: $\text{Israel}$ (widely accepted total of $9$ nuclear powers)
  • Black = NATO members in the nuclear-sharing scheme (the weapons are American and would be transferred in wartime): $\text{Belgium},\;\text{Italy},\;\text{Germany},\;\text{Netherlands},\;\text{Turkey}$
  • Green = Former possessors: $\text{Belarus},\;\text{Kazakhstan},\;\text{Ukraine}$ (inherited Soviet stockpiles; warheads returned to Russia) and $\text{South Africa}$ (built & tested; later dismantled)

Lecturer’s Personal Connection & 1995 Revision

• Professor has taught this topic since the $1970\text{s}$; major rewrite in $1995$ after:
  • Sabbatical with University of Maryland Asian Division
  • Stationed in Tokyo $08/1995$, bullet-train to Hiroshima $08/05/1995$ to attend $50^{\text{th}}$-anniversary Peace Memorial (>1,000,000 attendees)
  • Emotional impact of the park containing preserved ruins; prompted a fresh perspective, though core judgments unchanged

Framing the Controversy

• Only the United States has used nuclear weapons in war → moral assessment splits Americans into “honor/necessity/pride” vs. “nefarious/immoral” camps
• Instructor urges students to reach a personal binary conclusion: virtually no middle ground

Late-War Strategic Context

• Germany surrendered $05/08/1945 \;(V!E\;Day)$, but Pacific War raged on
• Cold War signs already visible:
  • First U.N. Conference $04/25/1945$ (San Francisco)
  • Potsdam Conference $07/1945$ with Churchill → Truman → Stalin; alliance fraying, Soviet viewpoint neglected in most U.S. narratives
• Island-hopping carnage shaped U.S. expectations for a mainland invasion:
  • Iwo Jima $02/19–03/26/1945$: $\approx26,000$ U.S. fatalities
  • Okinawa $04/01–06/22/1945$: $\approx50,000$ U.S. fatalities
• Air-sea strangulation of Japan ongoing; Tokyo fire-bombing $03/09–03/10/1945$ killed $\approx80,000$ in two nights, yet government showed no surrender inclination

Truman Takes Office & Invasion Plans

• FDR dies $04/12/1945$ → Truman sworn in; only informed of Manhattan Project $04/25/1945$
• Tentative invasion schedule:
  • Operation Olympic (Kyūshū) $11/1945$
  • Operation Coronet (Honshū) $03/1946$

Origins & Development of the Manhattan Project

• Einstein–Szilárd letter $08/1939$ warned FDR of German atomic quest
• FDR created Uranium Committee → full Anglo-American Manhattan Engineer District $1941–1942$ (Soviets excluded)
• Key sites:
  • Chicago: first controlled chain reaction $12/02/1942$ under Stagg Field stands (physicist $Enrico\;Fermi$)
  • Oak Ridge, TN: U-$235$ separation
  • Hanford, WA: plutonium production (ongoing waste-leak concern; Yucca Mountain debate)
  • Los Alamos, NM: design & assembly (Dir. $J.\;Robert\;Oppenheimer$; military lead $Gen.\;Leslie\;Groves$)
• Trinity test, Alamogordo $07/16/1945$: yield $\approx20,000$ tons TNT; Oppenheimer quotes Bhagavad Gita: “Now I am become Death …”

Policy Deliberations

• Interim Committee chaired by Sec. War $Henry\;Stimson$ reported $06/01/1945$:
  1. Use bomb against Japan ASAP
  2. No prior warning
• Potsdam Declaration $07/26/1945$ (Truman & Churchill) demanded unconditional surrender, threat of “prompt and utter destruction” (bomb not named)
• Japanese Premier Suzuki’s response word mokusatsu interpreted by U.S. press as “reject,” accelerating go-ahead

The Bombings

• Hiroshima $08/06/1945$
  • Bomb: “Little Boy,” U-$235$ gun-type
  • Immediate deaths $\approx70,000$; by $1946$ cumulative $90,000–140,000$ (blast, burns, radiation)
• Nagasaki $08/09/1945$
  • Bomb: “Fat Man,” plutonium implosion
  • U.S. headline same day: “Atomic Bomb Hits Nagasaki; Soviets Enter War”
• Photos show mushroom clouds, city-wide annihilation, surviving dome ruins (now Peace Park)

Soviet Entry & Timing

• At Yalta $02/04–02/11/1945$ USSR promised to join Pacific war within $90$ days of German surrender → deadline $08/08/1945$
• Red Army began massing in Korea; U.S. feared partage of victory
• Actual Soviet offensive in Manchuria began $08/08/1945$, but Japan capitulated before USSR could claim major spoils

Japanese Surrender

• Emperor Hirohito recorded surrender speech night $08/14/1945$ → broadcast $08/15$ despite attempted military coup
• Formal signing aboard USS Missouri $09/02/1945$ (VJ Day)

Competing Explanations for U.S. Decision

1. Save Lives / Prevent Invasion
   • Pentagon estimates: invasion could cost $\approx1,000,000$ U.S. casualties & $\ge2,000,000$ Japanese
   • Truman’s memoir: atomic bomb “merely another powerful weapon … saved millions of lives”
2. Racial Attitudes
   • Long-standing anti-Asian prejudice may have lowered ethical barriers; yet Allies fire-bombed German cities too, suggesting weapon likely would have been used in Europe had it been ready earlier
3. Demonstration Option Rejected
   • Only $2$ bombs available; risk of dud; uncertain Japanese reaction
4. Diplomatic Leverage vs. USSR
   • Quotes from Truman (“hammer on those boys”), Stimson (“equalizer”), and Secretary of State-designate James Byrnes (“make Russia more manageable”) imply goal of postwar bargaining power
5. Momentum & Cost
   • $\$2\text{ billion}$ invested; new technology historically deployed immediately in total-war context

Human & Material Cost of WWII (Select Figures)

• Military deaths (approx.)
  • USSR $13,600,000$
  • China $3,500,000$
  • Germany $3,250,000$
  • Japan $1,506,000$
  • United States $300,000$
• Civilian deaths (approx.)
  • China $\ge10,000,000$
  • USSR $\approx7,700,000$
  • Japan $\approx350,000$ (pre-nukes air raids killed $\approx240,000$)
  • United Kingdom $67,000$; United States (continental) $\approx0$

Post-War & Long-Term Implications

• Atomic monopoly gave U.S. status, perceived security shortcut, and tool for coercive diplomacy → fed early Cold War brinkmanship
• Sparked global nuclear arms race, redefining strategy (deterrence, MAD)
• Moral precedent: acceptance of civilian populations as deliberate targets, echoed by axis & allies’ area bombing campaigns (e.g., Hamburg, Dresden, Nanjing Massacre)
• Ongoing legacy issues:
  • Environmental contamination (e.g., Hanford, global waste repositories)
  • International non-proliferation regime (NPT, CTBT, nuclear-sharing debates)

Key Take-Home Questions for Students

• Does the scale of projected invasion casualties justify first-use of nuclear weapons?
• To what extent did geopolitical maneuvering (vs. military necessity) drive the timing?
• How did precedent of strategic bombing against civilians frame leaders’ moral calculus?
• What lessons should contemporary policymakers draw regarding deterrence, proliferation, and humanitarian law?