Japanese attack Brits/Dutch/French but NOT American territories.....?

A thought now transferred over from a diversion from a "how to avoid disaster at Pearl" thread:

*IF* the Japanese decide against attacking American interests in the Pacific, but go for strictly British/Dutch/French holdings in Southeast Asia, do NOT attack Pearl Harbor, Guam, Midway, or the Philippines....what is likely to happen? How long before clash of interests involves Americans? When do you think America would enter the war against Japan, and under what circumstances? How "eager" would America be to get involved or declare war on Japan?