Q-ball may be correct in that any approach at PI would have brought the Americans into the war.
Let me go back and re-iterate. There is no doubt Japan was going to declare war on the US. Roosevelt was not going to get an option. He wanted to be involved in Europe but had very liitle public support. Had Hitler not been stupid enough to declare war on the US, Rossevelt would have had a public focused upon defeating Japan and an even stronger resistance to Europe (why get in a war in Europe when you are already attacked in the Pacific).
In looking at political solutions in the Pacific,
1) Rule out the suprise attack factor, as it was not the Japanese plan, if was an accident (fatal at that and one could argue that the attack plan timeline was too precise for the state of communications of the era). But now you don't have the "revenge" motivator (which BTW still prevades a lot of Americans today).
2) Hitler doesn't declare war so the US is fighting only in the Pacific (in it's unprepared state).
Are there scenarios where the Japanese can win a political victory thru war? Would the US public feel passionate enough about the Phillipines to tolerate 2yrs of war, with no real success (or can the US get success in 2 years?) Would any European country have demanded a continued war in by the end of 1942 or would they have at least entertained a peace. The Japanese were not in India and given the trouble England had controlling India would probably have welcomed some assurances (believable or not) that Japan would leave India in their hands. Churchill was very pro keeping India as a colony.
Would the US have actually followed War Plan Orange? Which may have been fatal.
I believe these are plausible scenarios (and others), given the political environment of the time.
