How would America respond to a Japanese declaration of war on Britain/France during fall of France

Say that when Italy jumps in on Germany's side Japan also jumps in like a vulture. Japan seems to think the war will be over soon and goes around America, being careful to avoid any accidents. Japan seems to want French Indo-China, the Dutch East Indies, and to be more flexible when it comes to British possessions.

How does the US respond? And if America doesn't immediately join the war can Britain remain in the fight? If America joins without being attacked does this change the 1940 election?
 
Previously the US had enacted some low level trade sanctions or restrictions with Japan. Getting to the Embargos Acts of 1941 18 months early is not to difficult given the attitude towards Japan of many US citizens.

The collapse of France panicked the US into the mobilization legislation of 1940. That will definitely occur, and X2. OTL All Army and navy reservists were called to active service, the National Guard mobilized and taken into Federal service in the active Army. Provision for inducting over 700,000 volunteers and conscripts in 12 months. A blank check handed to the Depts of War and Navy to purchase modern arms. Efforts will be made to accelerate all that.

Perhaps the most important change in US mobilization will be getting to legislation that allows centralized Federal control of arms production and resource allocation. One of the hindrances of the 1940-41 mobilization period was the retention of a peace time economy. Free market meant the military arms program did not have priority for steel, copper, rubber, chemicals, or anything else. OTL the problem was not solved until legislation accompanying the DoW vs Germany & Japan gave the Federal government control of resource allocation. Enact that a year early & the US gets close to its production levels of mid 1943 in mid 1942.

Note that the Phillipines will be directly astride the Japanese LoC to the British and French colonies. And, the US Asiatic fleet, the 4th Marines, and Army 15th Infantry will all still be in China and directly in the line of fire adjacent to the British and French garrisons & gun boat fleet in China. Shooting incidents between Japanese & US naval, ground, and air forces are near certain.
 
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Japan may want to prevent British war materials coming via British Columbia, and thus attacks Esquimalt and Vancouver. Now that would rattle Washington DC I'd say.

But can Japan strike that far?
 
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How does the US respond? And if America doesn't immediately join the war can Britain remain in the fight? If America joins without being attacked does this change the 1940 election?

None of the likely Republican or potiential Democratic candidates had a alternative to Japanese aggresion that was significantly different to Roosevelts policies. The sinking of the Panay, the beating of a US diplomat, the wide violation of trade agreements for Chinas markets, atrocities like the Rape of Nanking, had been mildly dealt with, negotiated over, overlooked, ect... by the US government. Wilkie & the others had very little to offer in terms of peaceful methods for halting Japans aggresion.

Keep in mind there was a significant economic factor here. US business in the China trade had already been severely damaged by Japans occupation policies. The threat of Japanese control of key resources like Indochinas rubber and rice, Dutch East Indies oil, Maylasian Tin, ect... spread panic among US business OTL in 1941. Japan attacking the French and British in June 1940 will do exactly the same. There will be huge pressure to take action directed at all the candidates of the 1940 election.
 
Japan may want to prevent British war materials coming via British Columbia, and thus attacks Esquimalt and Vancouver. Now that would rattle Washington DC I'd say.

But can Japan strike that far?

The carriers could probably reach that far, though I think chances are slim of the task force not being spotted.
 
The carriers could probably reach that far, though I think chances are slim of the task force not being spotted.
It's an extra 1000+ miles each way vis a vis Pearl AFAIK. They deck loaded fuel drums to reach Pearl, and even then the DD's were rather low on fuel (there was a concern that if they stayed for a 3rd wave some of the DD's might have to be left behind AFAIK), extra 2000+ miles, gonna need more tankers or to abandon the DD's, given Japan's limited number of tankers, and limited number of DD's, they'd probably not bother
 

raharris1973

Gone Fishin'
Donor
Monthly Donor
Note that the Phillipines will be directly astride the Japanese LoC to the British and French colonies.

Yes, much like Vladivostok was directly astride the Japanese LoC with Korea. And much like Switzerland was directly astride German LoCs to Italy.

And, the US Asiatic fleet, the 4th Marines, and Army 15th Infantry will all still be in China and directly in the line of fire adjacent to the British and French garrisons & gun boat fleet in China.

The American units would not be particularly more tangled with British units than either the US or UK units were with Japanese or Chinese in 1937.

Shooting incidents between Japanese & US naval, ground, and air forces are near certain.

shooting incidents can = immediate war, they do not have to mean immediate war. Shooting incidents at sea in the Atlantic didn't mean war immediately.

getting to the Embargos Acts of 1941 18 months early is not to difficult given the attitude towards Japan of many US citizens.

No, it is not too difficult at all to get to a total embargo under the OP's circumstances, but embargo in May-June 1940 =/= US-Japanese war.

For the Japanese, it certainly indicates American economic and diplomatic hostility, but not US attack.
 
The carriers could probably reach that far, though I think chances are slim of the task force not being spotted.
The logistics just don't make sense for anything more than a suicide run--Vancouver is 2500+ miles further from Japanese territory than Pearl Harbor is, and unlike the central Pacific, the northeastern Pacific does not have numerous islands that you can turn into supply depots. The only way it would work is if Japan seized one or more of the easterly Aleutian islands, and that guarantees American entry into the war without a crippling first strike.
 

nbcman

Donor
In June 1940 as compared to Dec 1941 (dates of refit taken from combinedfleet.com's TROMs for the respective ships):
No Shokaku and Zuikaku CVs (they were not ready until 1941); no Shoho or Zuiho CVLs (they were converted sub tenders which were completed in 1940/41). Kaga had just started a major refit in May 1940. Kirishima was in a refit until Nov 1940. Fuso was in a refit until April 1941. A6Ms were about to come out (July 1940) so the IJN CV front line fighter would be A5Ms which had a range of about 40% and a max speed of 80% of the Zero.
So the IJN would have 3 CVs (Akagi, Soryu, Hiryu), 2 CVLs (Ryujo & Hosho), 3 BC/BBs and 5 older BBs for use in June 1940 at best.
 
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  1. No oil for Japan
  2. Japan declares war on the United States
  3. Germany declares war on the United States
  4. Neither the United States or Japan are ready for war, a very messy first engagement probably won by Japan at high cost.
  5. American aircraft get sent to fight in the Battle of Britain increasing Luftwaffe losses, seriously affecting Barbarossa
  6. America gears up for war,and proceeds to produce the Axis into Oblivion.
 
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I don't believe the Dutch or Portuguese got a declarion of war. Why would the British and French? They would simply be attacked. It would be out of character for the Jaoanese government at the time, as IOTL, they pretty much waited until the Germans defeated countries before claiming their colonies due to their alliance with them.
 
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