Would Britain join an American war against Japan?

Would Britain join the United States against Japan in exchange for American entry into Britain's war?

Potentially, but Churchill would hold considerable bargaining power and would likely demand a significant deal.

A viewer asks whether Britain might promise to enter a US-Japanese war if the United States joined Britain's war. That bargain was possible rather than automatic. With Britain still neutral toward Japan, the decision and negotiating leverage would sit heavily with Churchill. Removing Pearl Harbor changes alliance formation from an immediate response to aggression into a transaction shaped by each side's military needs.