For all those recent historians, back in the late 30s and early 40’s the American forecast was nowhere certain.
Most people paid more attention to Germany for the first part of WWII, because of the American policy of Germany first, but many quickly forget that Dec 7, 1941, wasn’t just a US/Japan strategy.
Within that same month, Japan had launched a seven pronged thrust throughout the east. Insofar as the projection of power was concerned, immediately after Pearl Harbor, Japan controlled over 1/2 of the world’s surface, from India to the west coast of the Americas and it was in no ways certain they weren’t about to invade the Americas.
Immediately after Pearl Harbor, there were no British or American ships patrolling either the Pacific or Indian Oceans, leaving 1/2 the world’s surface open to Japanese attack.
It wasn’t really until Midway that they were defeated, either. It’s an interesting perspective, that first 6 months of the war. Midway isn’t talked about enough as the first pivotal turning point, it was before El-Alamein or Stalingrad.
Prior to Midway, the Axis had won every battle.