One of the reasons often used to justify the use of nuclear weapons is that the alternative strategy, firebombing and invasion of Japan, would have caused much more death and destruction for both Americans and the Japanese. But I wonder, why was an invasion the necessary alternative?

As I understand, Japan was running low on resources such as oil, rubber, and steel, even from the beginning of the war. If the invasion of the homeland looked so costly for both sides, why was it deemed necessary?

I'm not aware of any allies Japan could have counted on to supply it; why not maintain a blockade and wait them out? It seems that that would have cost less in terms of American casualties.

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    @MarkC.Wallace Not sure if you're asking me to clarify or just adding on to my question, but I think I can answer some. For the effectiveness of the blockades, the question is how many ships get through. For that, they need resupply ships coming in in the first place. A Japanese ship would need to leave and re-enter. In a blockade, a round trip would be more difficult. As far as allies resupplying, the Axis powers google lists are Germany, Japan, and Italy, so two of those were out of commission at the time. Anyone resupplying Japan or Japanese ships would be subject to the same treatment.
    – user151841
    Commented Dec 23, 2015 at 18:49
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    The same answers about the blockade apply to resupply by air. Who nearby is going to resupply them? China? Russia? The Philippines? If Japanese planes manage to get in and out, where are they going to land to pick up supplies? Remember planes back then had no where near the range they do today.
    – user151841
    Commented Dec 23, 2015 at 18:52
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    As far as other options, I understand that Japan offered terms of surrender that included the sovereignty of the Emperor, but the US did not accept this, for whatever reason (that's why I'm asking-- that some historian who knows the reasons would answer). Instead the US chose, pursued, whatever-- complete surrender. Why, is what I'm asking.
    – user151841
    Commented Dec 23, 2015 at 18:54
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    @user151841 That is a common misconception. Japan never seriously made this offer, and when such attempt were made they were don't to the Soviet-union, who never forwarded it to US. About the seriousness of such surrender attempt: even after the two bombs and the Soviet invasion it took several days to the Emperor and government to proceed to surrender. Actually, the Emperor was still insisting on staying in power at this point, too.
    – Greg
    Commented Dec 24, 2015 at 3:33
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    @Greg Any reference on the "still insisting on staying in power at this point" part? Or do you actually mean retaining the throne? Because you make it sound like he wanted to "keep" actual governmental powers, which he essentially did not exercise in practice in the first place.
    – Semaphore
    Commented Dec 24, 2015 at 6:23

3 Answers 3


During the war the policy of the United States Congress and the President and the chiefs of the armed services was to attack Japan and Germany with the full and undivided power of the country until they surrendered absolutely and unconditionally. This was made abundantly clear at multiple points, including the joint Proclamation Defining Terms for Japanese Surrender issued after the Potsdam conference:

The prodigious land, sea and air forces of the United States, the British Empire and of China, many times reinforced by their armies and air fleets from the west, are poised to strike the final blows upon Japan. This military power is sustained and inspired by the determination of all the Allied Nations to prosecute the war against Japan until she ceases to resist....

....The full application of our military power, backed by our resolve, will mean the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland.

Proclamation Defining Terms for Japanese Surrender
Issued, at Potsdam, July 26, 1945 By The United States, England and China

Surrender or the US, British Empire, and China will use the "full application of our military power" to deliver the "utter devastation of the Japanese homeland." Is that clear enough? Minimizing casualties was not on the list of objectives.

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    Blockade would not minimize civil casualties. Japan essentially would not have food, and they would just sacrifice the food and other basics from civilians to keep the 1-1.5 million soldier ready to fight. That is potentially hundreds of thousands if millions of famine casualty. See recent examples in e.g North Korea.
    – Greg
    Commented Dec 24, 2015 at 3:40
  • For once I agree with TylerDurden. While @Greg is correct about what would actually happen, American leaders either did not know or did not consider that possibility. This is evidenced by the fact that the official (constructed post factum) justification for the atomic bombings insisted they saved lives by averting an invasion, but never argued that a hastened surrender saved lives from death by famine. An omission that continues to plague populist answers such as this even though it is, imho, the most absolute defence of the bombings.
    – Semaphore
    Commented Dec 24, 2015 at 6:18
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    @Semaphore Blockade is rarely a choice of tool (especially as the only tool) when a country is capable to fight. Actually a similar tool (embargo) brought Japan into the was (or at least they like to say it), so I guess none was even considering it as a solution.
    – Greg
    Commented Dec 24, 2015 at 19:10
  • @Greg Many members of the American military leadership have expressed opinions to the effect that the atomic bombing was unnecessary because a blockade would have brought Japan to her knees without an invasion. Regardless of whether they are correct (I have no wish to start a debate on this here), this would suggest the concept was entertained by Allied high command.
    – Semaphore
    Commented Dec 24, 2015 at 19:54

Because only an invasion, or a credible threat of it, will have brought unconditional surrender. The latter let the Allies neutralise the strategic threat from Japan, by replacing their military dictatorship with a pacifist democracy and reducing the Emperor to a figurehead.

There's some possibility that Japan may have fought on, at least to defend the home islands, as evidenced by an attempted coup to prevent the acceptance of surrender, despite being nuked. Before the nukes and Soviet invasion of Manchuria, the government was actually unwilling to surrender. How much of the surrender was because of the nukes or because of the Soviets is up for debate.

On that note, there's the spectre of the Soviets rushing into Japan before the US, as they did in East Germany, and as they half-did in Korea. If the US was unwilling to invade, that's basically inviting the Soviets to take their place and gain a surrender favourable to them.

Besides, blockades aren't as great as you make it out to be. Starving and isolating an entire country doesn't exactly endear yourself to the population. We have at least two real-life examples of what happens: North Korea and Iraq between the gulf wars. Both regimes are/were stable and hostile as ever. Compared to them, the outcome for Japan was a miracle.

  • Soviet invasion started on August 9, 3 days after the Hiroshima bombing.
    – Alex
    Commented Dec 24, 2015 at 3:20
  • Even after the nukes and soviet invasion the position of government on surrender did not change. the ministers related to Navy blocked any surrender attempt. The only change was the they asked out the opinion of the Emperor, who (at the first time) was willing to talk about surrender.
    – Greg
    Commented Dec 24, 2015 at 3:36
  • Opinions and assertions with little evidence and no references in support. This does play to the nonacademic but established biases of most readers on this site, though, so I guess that's not needed.
    – Semaphore
    Commented Dec 24, 2015 at 6:09
  • @Semaphore I don't know if references are required since the timeline of events is well known. If you want to question the finer points such as the willingness of Japan's surrender at various points in time, those can go in separate questions because afaik nothing I've asserted here is controversial. If you think the facts don't support this answer you're welcome to provide your alternative answer. Commented Dec 24, 2015 at 6:18
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    @congusbongus "..will have brought unconditional surrender" But my question is, why was the US insistent on unconditional surrender? Why couldn't they accept a few conditions, and avoid both a land invasion and nuclear bombing?
    – user151841
    Commented Dec 24, 2015 at 23:22

The United States already had crippled Japan with an embargo, however, they knew from other invasions in the Pacific that they wouldn't surrender, so the only options were to invade, or use the new nuclear technology, which did the trick.

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