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With a POD preferably after 1930, have Japan be at war with the west, including the US, by 1940. Bonus points if you can get war to break out in Europe on OTL's schedule.

I'm thinking one of the best places to start would be Panay Incident or something similar. In OTL the Japanese government went to extreme lengths to smooth over the incident. Maybe if they were much more callous it would provoke an earlier embargo.

Another good place to start might be somehow having Japan abandon the Washington treaty early. I have no idea what might trigger this though. Maybe more vocal protests over Japanese activities in Manchuria?
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