At the time of the Pearl Harbor attack, it is worth recalling the status of the so-called ABCD alliance:
America-- still strongly isolationist despite providence of war material to Britian, Russia and, to a lesser extent, China.
Britain-- hardly capable of launching an offensive, having barely survived Germany's onslaught tge year before.
China-- Engaged in a civil war of their own, temporarily on-hold due to the Japanese invasion.
Dutch -- An impotent little country under nazi occupation barely able to govern Indonesia.
Japan had the choice of turning northward (Russia) for its oil resources. Since dictators trust each other more than they do free countries, however, the choice was made to enter a non-agression pact with the Russians prior to launching the attack on Pearl Harbor-- the exact same M.O. Hitler followed prior to attacking Poland.
Naziism, Facism and Communism are all movements of the left. They disagree on little but methodology.
And, most importantly, which one of them was going to be the top dog.