An Anglo-Japanese alliance after the fall of France

If Japan joined Britain after the fall of France and the United States initially stayed out, how would the war and postwar politics change?

The alliance would speed victory in the Mediterranean and North Africa, and the United States would face strong pressure to enter before losing influence.

Japanese entry on Britain's side would revive the Anglo-Japanese Alliance. The Mediterranean and North African campaigns would probably end sooner, while Germany would still lose through a different sequence of events. American neutrality would then become difficult to sustain because an Anglo-Japanese victory could reduce US influence with Britain and upset the treaty-era status relationship among the three powers. The answer treats US entry as a likely political response to the coalition, although Congress could complicate the timing.