under what circumstances can you see "GO BIGGEST AND BADDEST AND DROP A F---ING A-BOMB ON 'EM" FDR having a "limited skirmish" with Japan? Under what circumstances can you see Japan's militarist warlords who launched a sneak attack on Pearl Harbor and conquered a quarter of a continent in a year consent to a limited war?
How can the IJN "knock out" the USN? Now, let's say they destroy the aircraft carriers and the battleships at Pearl. This is not outside the realm of possibility. It ultimately doesn't matter, b/c they don't have the capacity to deploy the manpower to take Hawaii.
by the end of the war, the US is rolling out ships every couple of hours. the usa in 1940 has 16 times the GDP of Japan, and twice the population. Japan had a lot of nice toys, but they had to fight a war against 300 million chinese, occupy SE Asia, keep sufficient garrisons in Manchuria and Korea to deter the USSR AND fight the most powerful nation in the history of earth. Who created atomic bombs from scratch in 4 years w/o much of an impact on the war effort.