jahenders
Banned
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?
While it would obviously take a different Japanese calculation, I think this would be a viable option. Japan would just have to conclude that the risk (probability * impact) of US involvement if the Japanese don't attack the US is lower than the risk (100% probability * risk) of getting the US involved by attacking PI/Pearl.
If Japan had attack UK/Dutch holding and not the US, the US would definitely up the rhetoric, embargoes, Lend Lease, etc. However, public sentiment for the US to get into a war for the British Empire still wasn't there.
Chances are the US would find a causus belli within 6 months (i.e. by Jun of 42), but it would almost certainly be with Germany. Assuming that's the case, it might be hard to justify the declaration of war including Japan if it scrupulously avoided attacks on US holdings. Even if Japan is included, the argument for Germany-first is going to be MUCH stronger, so the Pacific might be largely a backwater with the US on defense until 43.
So, if the Japan doesn't attack the US:
- The US likely won't enter the war until 3-6 months later and with an even stronger European focus
- Torch probably won't be until early 43
- Sicily is later in 43
- Probably no Coral Sea or Midway in 42
In general, had Japan not attacked the US, it might have set US involvement in the war back 3-6 months in Europe and possibly 6-12 in the Pacific.