See, there again is the gamer clashing with the historical gamer. American CAN defeat Japan easier first, so therefore, it should. However, Germany is in a stronger position to get all the VC it needs to win, therefore, wether America beats Japan or not, it wont make a difference, Germany will have already won. America has a MASSIVE economy, not only because it was historical, but so it can split its resources to both fronts, and be equal or greater to the axis power/s it faces on those fronts. America, as it did historically, work with the other nations to try and stem the axis advance, and then when it starts to stall, being hitting back and making a slow, but gradual, advance against the axis on all fronts. I think that is why Larry designed the US the way he did. In many of A&A’s pervious incarnations, in global versions anyway, there was always this issue that if America didnt focues on one front first, its would dissipate Americas overall impact on the game, and give the axis an strong advantage, if not an outright win. Now, Larry has made the US an economic beast, dwarfing all other players economy. Now the US no longer needs to focues on one front first, as they could split their wartime encomy, sending 50IPCs to Europe and 40IPCs to the Pacific and be matching or beating the economies of its enemies. And, when you add the portion of the US economy commited to whichever front to that of allies fighting with the US in the same front, it will always be more then what the Axis power has.
It really comes down to following the letter of a game rule, as opposed to playing to the spirt of the rules and the game.