December 7, 1941. What if?

It would have seriously set back American capabilities in Hawaii, but I doubt if Japan could have carried out an invasion of Hawaii without seriously impacting its abilities to conquer in Asia.

Nagumo was concerned about the American carriers, which had not been at Pearl Harbor, as the Japanese had expected them to be. Not knowing where they were, he was worried that they could attack his fleet when they were unprepared to defend themselves.

Nagumo's strike force included six carriers, Akagi, Kaga, Hiryu, Soryu, Shokaku and Zuikaku. Akagi and Kaga were comparable to the USS Lexington class. The other four roughly compared to the USS Yorktown class. Against these we would have pitted USS Lexington and USS Enterprise, the only fleet carriers at Pearl. It can be argued that they didn't pose much of a threat, but remember that at Midway three American carriers were able to destroy four of these Japanese carriers.

Yamamoto depended on luck and daring in his battle plans. Nagumo, the pragmatist, wanted something a little more certain on his side. History may well agree with you that he screwed up. But History has the advantage of hindsight, and Nagumo didn't have that working for him.

Yes, the fleet would have had to pull back as they would not have had a fuel supply.

Japan could have captured the islands.

Japan then could have raised the ships and used them changing the totals and giving them a 40 ship advantage over what actually happened.

It has been said that if the Japanese advanced further after the bombing of Pearl Harbor, they could've reached the mainland of America with little to no resistance.

Of course, luck always plays a large part in wars.

What if the Radar operators recognized that the Japs were coming and all the US fighters were airborne when they arrived and all the ships were at sea? Would we have been able to counterstrike and have handed them a sound defeat that day?