Japan joins Britain after France falls

The scenario puts Japan beside Britain and the Free Powers on 25 June 1940, after France falls. Its essential departure from history is that the Second Sino-Japanese War never begins in 1937. Japanese-American relations would still be poor, and avoiding war in China would not remove the prospect of a later Pacific conflict. Some Japanese leaders considered a long war against America unsustainable because Japan lacked the infrastructure and operational depth to fight it alone. A further proposal was to make America declare war, hoping this would weaken domestic support for the conflict there. These constraints frame the proposed choice to join Britain after France falls.