US reaction if Japan attacks British colonies+DEI, but not US

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Deleted member 1487

What if the Japanese opted to gamble and attack the British and Dutch in 1941 without going after the Philippines and US holdings? I'd imagine they could attack earlier than IOTL and keep forces in reserve just in case the US opted to intervene. What would happen then if the US was left out of the Japanese offensives? How would the British react? Would the US public be interested in war?
 

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Problem: The General staff and the Admiralty. Both saw the Phillippines as a huge threat to the Japanese SLOC back to the home islands. And by the time of the OTL Pearl Harbor (should it really be a capital H in Harbor there?) attack it was the military that controlled the government.

So you need to get saner and more reasonable people in charge, but then those very saner and more reasonable people might well chose not to go to war and instead conduct further negotiations.

BTW: I'm not trying to throw a wrench in the idea, I've searched for the very same solution myself previously.
 
What if the Japanese opted to gamble and attack the British and Dutch in 1941 without going after the Philippines and US holdings? I'd imagine they could attack earlier than IOTL and keep forces in reserve just in case the US opted to intervene. What would happen then if the US was left out of the Japanese offensives? How would the British react? Would the US public be interested in war?

It is very tough to leave the US out of the war, they can cut the supply lines too easily from the Philippines. So a reserve that is able to keep the US from intervening takes quite a big bite out of the available Japanese fleet. You might be looking at much of the battleships and most of the carriers + the various escorts. Of course Japan may gamble, but I think the more successful Japan is the more likely a US intervention is, especially as Japan seemed prone to committing atrocities.

I guess they could attack earlier - but bear in mind the Japanese strength vs its enemies probably peaked about when they did make their move in Dec 1941.

Britain and the Dutch on their own would really struggle if the war in Europe is going on at the same time. But an earlier war before the carrier age could make an epic story!
 

Deleted member 1487

It is very tough to leave the US out of the war, they can cut the supply lines too easily from the Philippines. So a reserve that is able to keep the US from intervening takes quite a big bite out of the available Japanese fleet. You might be looking at much of the battleships and most of the carriers + the various escorts. Of course Japan may gamble, but I think the more successful Japan is the more likely a US intervention is, especially as Japan seemed prone to committing atrocities.
The thing I question is the US public's willingness to go to war in 1941, because it would mean declaring war on Japan, Germany, and Italy due to the Axis pact, which politically was too much for the public to stomach, even with greater Japanese aggression in the Pacific. Even though the isolationists were politically weakening by December 1941 the US public was still not interested in declaring war, they were willing to risk the Axis declaring war on them to supply Britain. So I could see the US taking provocative actions all over the place, but the public sentiment still stopping short of war, even if that meant an undeclared naval conflict in the Pacific and Atlantic.
 
Problem: The General staff and the Admiralty. Both saw the Phillippines as a huge threat to the Japanese SLOC back to the home islands. And by the time of the OTL Pearl Harbor (should it really be a capital H in Harbor there?) attack it was the military that controlled the government.

So you need to get saner and more reasonable people in charge, but then those very saner and more reasonable people might well chose not to go to war and instead conduct further negotiations.

BTW: I'm not trying to throw a wrench in the idea, I've searched for the very same solution myself previously.

No, I think you are right. You need a major shift in Japanese thinking on this.

Not saying it is impossible, but it needs to addressed in forming the P.O.D.

To answer the question, I don't think FDR can take the US into war over a Japanese attack on the Netherlands and Britain. More likely he severs diplomatic relations, and puts the country on a full war footing. The problem for Japan is that war with the US almost certainly *will* eventually come, but by the time it does, the U.S. will have made the Philippines and Guam much more difficult to conquer - and that doesn't even account for the U.S. naval buildup's progress.
 
Yes but. YNK

No, I think you are right. You need a major shift in Japanese thinking on this.

Not saying it is impossible, but it needs to addressed in forming the P.O.D.

To answer the question, I don't think FDR can take the US into war over a Japanese attack on the Netherlands and Britain. More likely he severs diplomatic relations, and puts the country on a full war footing. The problem for Japan is that war with the US *will* eventually come, but by the time it does, the U.S. will have made the Philippines and Guam much more difficult to conquer - and that doesn't even account for the U.S. naval buildup's progress.

I agree that the Japanese as per OTL are very unlikely to take this gamble. But, IF they did, I think you're right that the US won't declare war instantly to help the European colonies.

So, assuming as quick or quicker occupation of Malaya, the DEI and Burma... If the Japanese then offer a cease fire to Britain and take no further aggressive actions, what does the US do? Yes it could stomp Japan whenever it wanted but what would the excuse for DOW be?
 

Deleted member 1487

No, I think you are right. You need a major shift in Japanese thinking on this.

Not saying it is impossible, but it needs to addressed in forming the P.O.D.

To answer the question, I don't think FDR can take the US into war over a Japanese attack on the Netherlands and Britain. More likely he severs diplomatic relations, and puts the country on a full war footing. The problem for Japan is that war with the US almost certainly *will* eventually come, but by the time it does, the U.S. will have made the Philippines and Guam much more difficult to conquer - and that doesn't even account for the U.S. naval buildup's progress.


The problem for the US then is that the British would likely be defeated by then. Britain under attack by Germany, Italy, and Japan would likely be in a bad spot without the US in the war, even with the USSR a factor. The US isn't going to be able to politically join the war before mid-1942/1943 IMHO and a stronger Japanese attack on Britain, plus being able to conquer and build up in the DEI without molestation, would given them the ability to really carry the offensive to the Indian Ocean, which would really spell death for the British if they then lose India or enough shipping. I mean if the Japanese have the resources to base out of Madagascar the British empire is over and the Persian LL route is pretty much cut. By the time the US enters the war they will either have to go against Japan or Germany, which probably precludes the North African campaign ITTL if they opt for the former.

As to PI, despite it being harder to invade due to preparations, isn't its forward position too vulnerable to really enable it to be supplied? Isn't that the reason that the US pulled its fleet back IOTL to Hawaii?
 

Deleted member 1487

I agree that the Japanese as per OTL are very unlikely to take this gamble. But, IF they did, I think you're right that the US won't declare war instantly to help the European colonies.

So, assuming as quick or quicker occupation of Malaya, the DEI and Burma... If the Japanese then offer a cease fire to Britain and take no further aggressive actions, what does the US do? Yes it could stomp Japan whenever it wanted but what would the excuse for DOW be?
Due to deals with Germany isn't that really not an option for them? I mean they did sign on to no separate peace deals IOTL.
 
Tricky

Due to deals with Germany isn't that really not an option for them? I mean they did sign on to no separate peace deals IOTL.
Well, if the UK is only being supported by LL and not the US military it might simply have to drop out of the War by end 1942. As the long term outlook would be pretty poor.

Making whatever terms it could with Germany, Italy and Japan. Which would leave Germany in a better position to force at least a stalemate on the Eastern Front, possibly a Brest Litovsk Mark 2.

Anyway, I doubt that Imperial Japan would have had any qualms about offering Britain a separate peace deal if it suited them. Which it might well do in order to avoid the risk of clashes with the US
 
The problem for the US then is that the British would likely be defeated by then. Britain under attack by Germany, Italy, and Japan would likely be in a bad spot without the US in the war, even with the USSR a factor. The US isn't going to be able to politically join the war before mid-1942/1943 IMHO and a stronger Japanese attack on Britain, plus being able to conquer and build up in the DEI without molestation, would given them the ability to really carry the offensive to the Indian Ocean, which would really spell death for the British if they then lose India or enough shipping. I mean if the Japanese have the resources to base out of Madagascar the British empire is over and the Persian LL route is pretty much cut. By the time the US enters the war they will either have to go against Japan or Germany, which probably precludes the North African campaign ITTL if they opt for the former.

As to PI, despite it being harder to invade due to preparations, isn't its forward position too vulnerable to really enable it to be supplied? Isn't that the reason that the US pulled its fleet back IOTL to Hawaii?

The only thing really stopping the US going to war is the Nov 1940 elections and it does not really matter who wins.

And for all the reasons you have just given - ie the US having to go it alone after the British Empire is knocked out of the war is precisely why the USA's entry into the war would happen before that event.

There are many on this forum who believe that the US was just waiting for the right casus belli to enter the war - there are some who believe that it was already technically at war with Germany before Pearl Harbour

As for Pulling back - the USN Pacific fleet's main base is San Diego on the Western seaboard - the main fleet units were effectively forward deployed to Pearl Harbour - not withdrawn to it. It was believed that they would be safe there from the IJN while being able to sortie to support the PI in the event of any Japanese 'adventurism'.

PI does not really have the facilities to support a major fleet in 1940-41 and is much more exposed than Pearl Harbour - to say a surprise attack - which is still true even though the USN did actually fall victim to just that at PH!

Particularly after FIC fell into the Japanese Orbit.

So to have the USA Waiting until the Brits were defeated before declaring...or not declaring war would require a special kind of idiocy among the entire US Administration and I just don't see it.
 

Deleted member 1487

So to have the USA Waiting until the Brits were defeated before declaring...or not declaring war would require a special kind of idiocy among the entire US Administration and I just don't see it.
The issue isn't the administration, they wanted in the war much earlier than the US got involved IOTL, it was the issue of the public support for declaring war, which even in December wasn't there until the Japanese attacked. The US public was totally fine with an undeclared shooting war in the Atlantic to supply Britain and keep her in the war, but it stopped short of being willing to declare war on Germany, Italy, and Japan, as any DoW on one power would effectively mean due to the Axis treaty. Churchill and FDR were despairing about that in November; FDR had gotten merchantmen armed and the public behind the policy of aggressive armed neutrality, but was still short of getting them willing to declare it. Perhaps that would eventually happen if Britain seemed on the verge of defeat and/or the USN took enough losses in the undeclared naval war.
 
The problem for the US then is that the British would likely be defeated by then.

The British would be in a difficult spot, but it's just hard to see Britain bailing out of the war. Certainly so long as Churchill was in power, but even so...they had made it through the Fall of France and the Battle of Britain; the loss of Singapore is a blow, but certainly no worse than what was suffered in 1940. Lend Lease was in place already, and that will keep Britain fighting, even if victory is not possible without U.S. belligerency.

As to PI, despite it being harder to invade due to preparations, isn't its forward position too vulnerable to really enable it to be supplied? Isn't that the reason that the US pulled its fleet back IOTL to Hawaii?

Well, recall that MacArthur in 1940-41 had talked Roosevelt into thinking that the Philippines *could* be defended after all, if given the equipment and time; he was busy building a Philippine Regular Army that, backed by B-17's, could (so he argued) hold off a Japanese invasion indefinitely, so it wouldn't matter if the US Pacific Fleet could not reach or supply him for a prolonged period of time. Of course, Japan attacked while he was in the early stages of the buildup...

MacArthur was likely, as always, too sanguine in his estimate (and as always, self-serving in making that estimate); but it is hard to see how another six to twelve months do not make the Philippines a more challenging nut for the Japanese to crack. MacArthur will have more trained Philippine troops, more air assets, more radar. At the least, he could maintain a considerably more prolonged resistance, and inflict more casualties on the Japanese.
 
More on just what was earmarked for the Philippines, but never made it there before war broke out:

The shipment of supplies was dependent upon the number of cargo vessels available to the Army. This number was never large and the Navy, for a time, threatened even this limited supply. In September the Navy announced its intention to convert three transports to escort carriers. General Marshall protested this decision vigorously, pointing out to the Chief of Naval Operations that it would delay the delivery of much-needed reinforcements to MacArthur by over two months.28 Despite the favorable outcome of this protest, a large backlog of troops and approximately 1,100,000 tons of equipment destined for the Philippines had piled up in U.S. ports or depots by November. A group of shipping experts, including representatives from the War Department General Staff, Office of the Quartermaster General, the Navy, and Maritime Commission, met on 10 November to discuss ways of breaking the shipping block. As a result of this meeting a shipping schedule was established which recognized the priority of the Philippines over Hawaiian defenses and advanced the troop movements scheduled for mid-January to 17 and 20 December. Altogether, nine vessels were assigned to the Manila route, to sail in November and December. They would bring to MacArthur one light and one heavy bombardment group, a pursuit group, one reconnaissance squadron, a regiment of infantry, a brigade of field artillery, two battalions of light artillery, together with ground and air service units. Had these vessels, the last of which was to leave the United States on 20 December, reached the Philippines the Japanese would have faced a far stronger force when they landed on Luzon.

And for the Army Air Force:

By now the War Department was fully committed to an all-out effort to strengthen the air defense of the Philippines. General Arnold, in a letter to the commander of the Hawaiian Air Force on 1 December, expressed this view when he wrote: "We must get every B-17 available to the Philippines as soon as possible."42 His statement was not an exaggeration. On the outbreak of war there were 913 U. S. Army aircraft scattered among the numerous overseas bases. This number of aircraft included 61 heavy, 157 medium, and 59 light bombers and 636 fighters. More than half of the total of heavy bombers and one sixth of the fighters were already in the Philippines.43 (See Table 3.) Within a few months this number would have been raised considerably.

And air defenses:

Despite the arrival of reinforcements and the airfield construction program, the air defense system remained inadequate because of the shortage of antiaircraft artillery and aircraft warning equipment. MacArthur had requested warning equipment in September and had at that time presented a plan for the establishment of an air warning service. The War Department had approved the project and by mid- September three radar sets had been shipped with three more scheduled for shipment in October. In addition, $190,000 was allotted for aircraft warning construction, with an additional $200,000 to be included in the supplemental estimate for the fiscal year 1942 for the construction of three detector stations and one information center.

The one air warning service company of 200 men in the Philippines was entirely inadequate to the needs of the Far East Air Force. In November General Arnold recommended, and the Chief of Staff approved, the shipment of an aircraft warning service battalion to the Philippines. The 557th Air Warning Battalion was organized in the United States and on 6 December 1941 arrived in San Francisco, too late for shipment to the Philippines.

When war came there were seven radar sets in the Islands, but only two had been set up and were in operation. In the absence of the necessary equipment and personnel, USAFFE had organized a makeshift air warning service. Native air watchers stationed at strategic points reported plane movements by telephone or telegraph to the interceptor command at Nielson Field, which in turn relayed the information to Clark. It was this primitive system, augmented by the radar sets established at Iba and outside Manila, that was in operation when war came.

...

The War Department and the Air Forces continued to show concern over the antiaircraft defenses of the Islands, about which they did not have too clear a picture. A radio to General MacArthur for information elicited the reply on 27 November that an increase in armament was required and that detailed plans were being forwarded by mail. These plans were sent on 1 December but even before then War Plans had recommended the dispatch of three antiaircraft regiments and two antiaircraft brigade headquarters to the Philippines. These units were to utilize the equipment then in the Islands, thus reducing shipping requirements. Action on this proposal was begun at the end of November, when time had almost run out. When war came, the antiaircraft defenses in the Philippines were little better than they had been three months earlier.

If the war is delayed even another 4-6 months, there's a good deal more hardware deployed in the Philippines, and more trained personnel using it.

That doesn't make MacArthur's job a slam dunk. But it does make General Homma's job considerably harder.
 
Britain isn't going to bail out of the war in mid-42 even if by some miracle the US isn't in it yet. With US lend-lease flowing in, Germany stalling out in Russia and North Africa, and US entry imminent... it just isn't going to happen.

TCertainly so long as Churchill was in power, but even so...

Even if they toss Churchill out, they aren't going to quit the war. No one in the upper echelons of British power by this point was seriously contemplated the British making peace to the Axis, not after repeatedly breaking their word and using treaties for toilet paper.
 
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It seems unlikely the Japanese would try to advance further than their OTL take of British and Dutch possessions. India and Ceylon or Australia would require major army commitment and sea transport supply. Once the Burma road is cut it would be best to focus on China again with an extra front in play.

In fact there is little reason to even take Rabaul and Lae in this scenerio as all it would is antagonize the Americans for little gain.

USA would continue to support the Flying Tigers, "train" soldiers in Australia (base a few divisions there), Occupy any free french colonies and may lease some British bases in the Pacific.

Once the South Dakota BB class all come online in late 1942 (after USA congressional elections), the USA can afford to get aggressive.

Allow quiet use of Manila as a British-Dutch submarine base, transfer subs to Britain/Holland and allow use of the spares and torpedoes stored at Manila. Allow flying tiger like "Chinese" naval force to raid on Japanese shipping etc.
 
The US opinion polls show that the US public would support US entry into the war if Britain appeared to be on the brink of defeat. I think FDR could argue that a Japanese conquest of Singapore and attacks on Australia represented such a scenario.

Anyway, before that:

Massive reinforcement of the Philippines
Patrols from the Philippines following IJN units and broadcasting their locations in the clear
Shipments of Lend-Lease to Australia, Malaya, Burma and India through the war zones
Possibly a neutrality zone around the Philippines, in which Japanese units would be attacked on sight, analogous to the one of the east coast, ostensibly to protect US shipping.

The last three would result in de facto war quite rapidly.
 
If Japan doesn't attack the US the US will be flowing forces into its Pacific possessions which will become more and more threatening every week. Japan will have to deploy forces to keep an eye on what the US is doing. At some point somebody who has an itchy trigger finger or is just plain scared is going to screw up and the proverbial doo doo will hit the proverbial fan.
 
What if the Japanese opted to gamble and attack the British and Dutch in 1941 without going after the Philippines and US holdings? I'd imagine they could attack earlier than IOTL and keep forces in reserve just in case the US opted to intervene. What would happen then if the US was left out of the Japanese offensives? How would the British react? Would the US public be interested in war?

Is this before any invasion of USSR?

recall they would only gamble on Vichy Indochina before Germans-Soviets started death match.

maybe they move only on DEI? although that might be distinction without a difference?

how would British react to that ? did they have committed joint defense plan for DEI?
 
First, I don't think the Japanese are going to strike before the oil embargo, so something like this could only happen a few months earlier than the OTL attacks. Really, I can't think of any good reason why omitting the strikes on Pearl Harbor and the Philippines advances things.

Second, this really was the best Japanese strategic option, or second best after just folding in the face of the embargo.

Striking against the USSR doesn't get them the oil and chances of success are iffy at best.

Its better to wait for the US to come into the war than trying to eliminate them as a factor from the outset. First, you really can't eliminate the US as a factor with one surprise attack. Its a continental country that is the world's largest economy. If they lose the Pacific fleet they can always move in naval assets from the Atlantic. They can eventually replace the ships.

Second, having the US come to you fits better with the overall strategic concept of taking alot of territory, and defending it until the US and UK decide its just better to make a deal and concentrate on the war in Europe. That's alot harder to do if you open up with a direct act of aggression on the US. Make FDR have to convince Congress that the US has to come in to save the British empire.

Third, though people probably didn't grasp this, the Japanese advantage in carrier aviation in 1941-2 was big enough that they probably would have won a naval battle in the open ocean against a USN attempt at relieving the Philippines. The attack on Pearl Harbor was fairly risky and could have gone very wrong. Tactically, again it was better to make the Americans come across the Pacific to fight.

Fourth, the "reserve" people talk about being needed in case the US came in could have been the forces historically allocated to Pearl Harbor and the Philippines, which by definition were not used against Java and Singapore. They also only allocated ten of the fifty or so army divisions for the strike south, and this includes the Philippines campaign. There would have been enough for a reserve.

Without Pearl Harbor, in practice I suspect they could have taken Malaya, Borneo, Java, and Sumatra much the same way as the Japanese occupied Indochina. Burma would have been nice to cut the main supply route to the Chinese nationalists, but could have been left for later, and in the mean time you can use forces based in the nearby islands to make Rangoon unusable as a port.

In terms of what would have happened, I think FDR would have asked for and gotten a declaration of war on Germany, Italy, and Japan after the fall of Singapore and Tobruk, to rescue the British. This would have echoed what Wilson and Congress did in 1917. But it would have been very controversial, and it would have given the Japanese the chance to ambush anything on the way to reinforce the Philippines. And they already would have taken what they needed in the east Indies.
 
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