Which would have been more destructive for the Western Allies: Operation Unthinkable or Operation Downfall?

[Mr_Fanboy]

Which of the following would have been more costly for the Western Allies (the United States, the United Kingdom, etc.) in terms of blood and treasure that would have been spent: Operation Unthinkable (that is, a war with the USSR launched almost immediately after the defeat of Nazi Germany, with the goal of pushing Soviet forces out of Germany, Poland, and much of the rest of Central and Eastern Europe) or Operation Downfall (an invasion of the Japanese Home Islands in a world where the atomic bombings of Hiroshima and Nagasaki had not triggered that country's surrender)?

 

[History Learner]

Operation Downfall, no question.

 

[Corocora]

Operation Downfall would've been a humanitarian disaster, but having the two World Superpowers get at each other immediately after Germany's defeat in an already devastated Europe would be an absolute nightmare, and a solid recipe to destroy the Western Allies' domestic stability - or World stability for that matter.

 

[A Piece of History]

Operation Unthinkable would've been a short, but bloody affair and it would've either ended in a Soviet victory or a draw. (Any total war against the Soviet Union would involve invading Russia itself and the Red Army, which possessed a 2;1 advantage over the Allies in terms of manpower on the ground, could've just retreated back to the Motherland and form a defensive line, sacrificing Eastern Europe to the Allies. Also, Soviet industry was still located in the Urals, so the Soviet Union could just keep churning out war material for the Red Army, safe from Allied retaliation)

Now, as for Operation Downfall, we will never definitely know how many men the Allies would've lost if they went ahead with the invasion, but taking into account the experiences of US troops in the Pacific , these were the following estimates from American commanders of the casualty rates.

In a conference with President Truman on June 18, Marshall, taking the Battle of Luzon as the best model for Olympic, thought the Americans would suffer 31,000 casualties in the first 30 days and ultimately 20% of Japanese casualties, which he estimated would include the entire Japanese force. This implied a total of 70,000 American casualties in the battle of Kyushu using the June projection of 350,000 Japanese defenders (or 183,365 American casualties when the actual Japanese strength of 916,828 is taken into account).[100] Admiral Leahy, more impressed by the Battle of Okinawa, thought the American forces would suffer a 35% casualty rate (implying an ultimate toll of 268,000).[101] Admiral King thought that casualties in the first 30 days would fall between Luzon and Okinawa, i.e., between 31,000 and 41,000.[101] Of these estimates, only Nimitz's included losses of the forces at sea, though kamikazes had inflicted 1.78 fatalities and a similar number of wounded per kamikaze pilot in the Battle of Okinawa,[102] and troop transports off Kyūshū would have been much more exposed.

A study done by General MacArthur's staff in June estimated 23,000 US casualties in the first 30 days of Olympic and 125,000 after 120 days, fighting an assumed Japanese force of 300,000[97] (in actuality some 917,000 Japanese troops were on Kyushu,[98] which would imply x3.05 greater casualties or 381,000). When these figures were questioned by General Marshall, MacArthur submitted a revised estimate of 105,000, in part by deducting wounded men able to return to duty.[99]

The US Sixth Army, the formation tasked with carrying out the major land fighting on Kyushu, estimated a figure of 394,859 casualties serious enough to be permanently removed from unit roll calls during the first 120 days on Kyushu, barely enough to avoid outstripping the planned replacement stream.

The Battle of Okinawa was one of the bloodiest in the Pacific, with an estimated total of over 82,000 direct casualties on both sides: 14,009 Allied deaths and 77,417 Japanese soldiers.[109] Allied grave registration forces counted 110,071 dead bodies of Japanese soldiers, but this included conscripted Okinawans wearing Japanese uniforms.[110] 149,425 Okinawans were killed, committed suicide or went missing which was one-half of the estimated pre-war local population of 300,000.[109] The Battle resulted in 72,000 US casualties in 82 days, of whom 12,510 were killed or missing (this figure excludes the several thousand US soldiers who died after the battle indirectly, from their wounds). The entire island of Okinawa is 464 sq mi (1,200 km2). If the US casualty rate during the invasion of Japan had been only 5% as high per unit area as it was at Okinawa, the US would still have lost 297,000 soldiers (killed or missing)

So, the Americans were expecting piles of corpses, at the bare minimum, within 30 days of landing on Kyushu. 500,000 Purple Hearts were produced just for the invasion. By 2003, 120,000 of these medals were still in stock and in the years since, have been given to veterans who have served in Iraq and Afghanistan.

This isn't even taking into account that the Imperial Japanese Army was far from disarmed. The following numbers are from the amounts of war materiel turned over to the Allies after the Japanese surrender in OTL.

So, the imperial Japanese Army will still have tons of munitions and vehicles to throw against the invaders.


There's also this little diddy.

On Marshall's orders, Major General John E. Hull looked into the tactical use of nuclear weapons for the invasion of the Japanese home islands, even after the dropping of two strategic atomic bombs on Japan (Marshall did not think that the Japanese would capitulate immediately). Colonel Lyle E. Seeman reported that at least seven Fat Man-type plutonium implosion bombs would be available by X-Day, which could be dropped on defending forces. Seeman advised that American troops not enter an area hit by a bomb for "at least 48 hours"; the risk of nuclear fallout was not well understood, and such a short amount of time after detonation would have resulted in substantial radiation exposure for the American troops.[80]

Ken Nichols, the District Engineer of the Manhattan Engineer District, wrote that at the beginning of August 1945, "[p]lanning for the invasion of the main Japanese home islands had reached its final stages, and if the landings actually took place, we might supply about fifteen atomic bombs to support the troops."[81] An air burst 1,800–2,000 ft (550–610 m) above the ground had been chosen for the (Hiroshima) bomb to achieve maximum blast effects, and to minimize residual radiation on the ground as it was hoped that American troops would soon occupy the city

X Day would've been November 1st, 1945. In the worst case scenario, seven atomic bombs could've been used on Japanese targets and the American soldiers, even if they survived the initial landings, would be irradiated by invading an area which hasn't had time to recover from the radiation. In the best case scenario, 15 atomic bombs would've been used.

So Operation Downfall could've potentially been a bloodbath for the Allies.

 

[Zincvit]

Snip

I think you might have mixed up operation Downfall and operation Unthinkable.

 

[Korlan]

I think the codenames of the operations make perfectly clear which one the WAllies considered would be the worst for them :

- Downfall = " fall of the Japanese Empire "

- Unthinkable = " OMFG, we would all be in deep shit, better pray it doesn't happen "

 

[TxAggie]

Guess it depends on how far both sides want to prosecute Unthinkable, but if they want to push it all the way, it could finish off a generation of Europeans. Britain was on their final army. Germany was long past done (read in one book how the WAllies were shocked at how many bodies they found in the aftermath of Falaise were old men, and that was 1944). The Red Army was a fearsome force but they were at their limit of manpower reserves as well. Taking on the Red Army after its routes of 1944 and 45 is a little unthinkable in of itself, but the armies in Europe were just exhausted.

Downfall was guaranteed to be a hideous affair, but one that the US Army still had the manpower to prosecute and the Japanese would still defend even if they didn't. I don't know which hypothetical would be more bloody, but Downfall is the only one I see as plausible unless you set up some scenario where Unthinkable is very very short.

And while the potential American casualties are always brought up in Downfall, I can't even imagine what the Japanese ones would be like. Nonstop B-29 attacks, tactical nukes, an American army in the mood to shoot everyone - the destruction would biblical.

This isn't even taking into account that the Imperial Japanese Army was far from disarmed. The following numbers are from the amounts of war materiel turned over to the Allies after the Japanese surrender in OTL.

View attachment 567184


So, the imperial Japanese Army will still have tons of munitions and vehicles to throw against the invaders.

Given how it says Allies, I'm wondering how much of that kit was tied up in China and surrendered to the KMT or Soviets.

 

[A Piece of History]

Guess it depends on how far both sides want to prosecute Unthinkable, but if they want to push it all the way, it could finish off a generation of Europeans. Britain was on their final army. Germany was long past done (read in one book how the WAllies were shocked at how many bodies they found in the aftermath of Falaise were old men, and that was 1944). The Red Army was a fearsome force but they were at their limit of manpower reserves as well. Taking on the Red Army after its routes of 1944 and 45 is a little unthinkable in of itself, but the armies in Europe were just exhausted.

Downfall was guaranteed to be a hideous affair, but one that the US Army still had the manpower to prosecute and the Japanese would still defend even if they didn't. I don't know which hypothetical would be more bloody, but Downfall is the only one I see as plausible unless you set up some scenario where Unthinkable is very very short.

And while the potential American casualties are always brought up in Downfall, I can't even imagine what the Japanese ones would be like. Nonstop B-29 attacks, tactical nukes, an American army in the mood to shoot everyone - the destruction would biblical.



Given how it says Allies, I'm wondering how much of that kit was tied up in China and surrendered to the KMT or Soviets.

To clarify further, that is materiel from South Korea and the Japanese Home Islands given to US occupation forces

 

[BlackDragon98]

Would the Western Allies allow German forces to join them in the fight against the Soviets?
Also, would the Allies copy some German weapons that were extremely effective, like the Panzerfaust?
Because the Germans would be fighting on home turf and together with the Allies, I think they could successfully defeat the Soviets, despite the numerical advantage.
Allies would probably gain air superiority quickly and then use it to slaughter Soviet ground forces.
Soviet Fleet would also be outnumbered by Allied naval vessels and then annihilated.

And German forces in unconquered areas like Norway and Denmark could be swiftly rearmed and used to hold these places until Allied forces arrived in strength.
It would be every country in Europe against the Soviets, who will have a short and exciting time in Europe.

 

[Seandineen]

I think Unthinkable is more bloody, but worth it avoided a 46 year cold war, and destruction in the third world.

 

[fraa Jad]

Operation Unthinkable is not that difficult if you recruit the armies of the countries occupied by the USSR that they conscripted. The Bulgarian army did not engage in any combat during WWII until the Soviets declared war on Bulgaria and occupied it on the 8th of September, 1944 and subsequently threw the Bulgarian army towards Hungary, and then Austria.

EDIT: The USSR had previously sunk a ship flying a Bulgarian flag carrying Jewish refugees going to Palestine. And had bombed Varna without a declaration of war.

EDIT2: Varna was briefly renamed "Stalin".

 

[Ficboy]

Operation Unthinkable given that the Soviet Union was very strong and possessed more resources than the Western Allies combined (United States, United Kingdom, Canada, Australia, New Zealand and France).

 

[BlackDragon98]

Operation Unthinkable given that the Soviet Union was very strong and possessed more resources than the Western Allies combined (United States, United Kingdom, Canada, Australia, New Zealand and France).

Problem is, the main industrial, agricultural, and raw material region (White Russia) of the USSR was completely destroyed during the fighting on the Eastern Front or evacuated to the Urals.
Also the USSR was still dependent on Lend Lease for many foodstuffs and essential supplies.

 

[Ficboy]

Problem is, the main industrial, agricultural, and raw material region (White Russia) of the USSR was completely destroyed during the fighting on the Eastern Front or evacuated to the Urals.
Also the USSR was still dependent on Lend Lease for many foodstuffs and essential supplies.

However as far as sheer numbers and military strength is concerned the USSR would prove to be a major challenge to the Western Allies.

 

[jsb]

and it would've either ended in a Soviet victory or a draw. (Any total war against the Soviet Union would involve invading Russia itself and the Red Army, which possessed a 2;1 advantage over the Allies in terms of manpower on the ground,

The problem is US (even without allies) is bigger so long terms it should win?

Operation Unthinkable given that the Soviet Union was very strong and possessed more resources than the Western Allies combined (United States, United Kingdom, Canada, Australia, New Zealand and France).

Really..... USA/UK /etc controlled most of the world (and all the oceans) in 45 look at a map......

 

[Workable Goblin]

Operation Unthinkable given that the Soviet Union was very strong and possessed more resources than the Western Allies combined (United States, United Kingdom, Canada, Australia, New Zealand and France).

The Soviet Union most certainly did not possess more resources than the Western Allies combined, where are you getting that from? The United States alone had a substantially larger industrial base, massive natural resources, and a far less exhausted population than the Soviets (who were, in a lot of cases, reliant on American lend-lease for certain war materiel, e.g. trucks). The Soviets certainly had advantages and would in no way be easily defeated, but they were equally not going to easily beat the Allies, either.

 

[Ficboy]

The Soviet Union most certainly did not possess more resources than the Western Allies combined, where are you getting that from? The United States alone had a substantially larger industrial base, massive natural resources, and a far less exhausted population than the Soviets (who were, in a lot of cases, reliant on American lend-lease for certain war materiel, e.g. trucks). The Soviets certainly had advantages and would in no way be easily defeated, but they were equally not going to easily beat the Allies, either.

I see but regardless Operation Unthinkable would be very destructive for both sides of the conflict and millions would die with nuclear bombs involved.

 

[fraa Jad]

Having grown up in the East Block, no, it was shit. The '90s were heaven, after the fall of Communism.

 

[Workable Goblin]

I see but regardless Operation Unthinkable would be very destructive for both sides of the conflict and millions would die with nuclear bombs involved.

I was not saying it wouldn't be very destructive or deadly. However, your earlier statements about the balance of power in the conflict were just wrong.

 

[GuildedAgeNostalgia]

Wasn't the Soviet Union facing sever manpower shortages near the end of World War Two?
Wouldn't Soviet occupied country's quickly turn on the Soviets if the WAllies were willing to fight the Soviets?
Wouldn't the Soviet Union starve to death due to its reliance on American food imports and the destruction of its fertile land/farming population during the war?
Wouldn't the Soviet Union lose due to nukes?

Wouldn't the moment Operation Unthinkable happens, the war weary Soviet Military coup Stalin, fall back to its 1941 borders and make peace with the Western Allies because it just wouldn't be worth it?

There's the difference. Japan will fight to the death for their emperor. The Soviets fear nuclear annihilation more than they fear Stalin (this is an opinion and I could be wrong, but its the opinion I have for now).