Had the Japanese finished up in the Solomons and then occupied Australia, before their attack on the US, we’d have had a much more difficult job in the Pacific until after V-E day. Might have taken more years at the very least.
As it was, US subs, surface ships, and aircraft were not recognized for sinking Japanese vessels without verification from a disinterested source, so the US figure for sunk Japanese shipping was 8 million tons, per Jon Parshall.
The Japanese figure was 11 million tons.
During the conflict, I don’t think the US every put boots on the ground in Borneo, which had all the coal, iron ore, oil, and probably rubber Japan would need. But the Japanese couldn’t get it to the manufacturers on the home islands. As Parshall noted, most of that 11 million tons was sunk before the beginning of 1944, after that time it was difficult to find Japanese shipping to sink.
A huge percentage of that was by our submarine fleet, I’m seeing 55%. The Japanese didn’t figure out anti-submarine warfare like the Brits and US did.
All that was accomplished with faulty torpedoes the first half of the war.
After Perl Harbor the Germans had 6-9 months to knock the Soviets out of the war in order to have a chance to at least not totally lose the war.
The only combination that could have beat the Axis was UK, US and Soviet Union all fighting at the same time against the Axis. 2 of the 3 would not be enough to defeat the Axis.
Hitler was not only evil but also stupid for bringing about this alliance against him.
Of course the US was heavily involved in the war prior to Perl Harbor.