Seeing a lot of American talking faces making points similar to this in the past few days...
Not cool. USA was already supplying literal ship loads of weapons to Europe (UK) before the pearl harbour thing. They were risking U2 infested waters to supply essentials.
Pearl Harbour didn't even necessarily need them to engage two enemies on two fronts. They could've just gone after the Japanese and not bothered with Mr. Toothbrush Mustache.
America was not a perfect nation, but good men within their powers tried their best.

