amphibulous
Banned
Because Churchill and Roosevelt had assured the other that a Japanese attack on the possessions of either country would result in a declaration of war from the other.
No.
1. The Japanese have to know of such a thing for it to inform their actions; the most FDR can offer WC is private goodwill
2. FDR can't make a meaningful commitment like that without having it ratified by Congress; this never happens - and can't
3. If he declares war to defend British imperialism then Congree overrides him: it isn't viable
I.e. you have just imagined a big chunk of WW2 history...