What if the Japanese leadership decided that an attack on Pearl Harbor wasn't enough to 'scare' America out of a major war. They decide on a plan to invade Hawaii, and then use the islands as a negotiating chip against the USA.
So:
-Could Japan pull off an invasion of the Islands?
-What would be the long term consequences on the Pacific War?
-Might Japan prop up a puppet government? I know Hawaii was added to the USA a little over fourty years before, and I don't know how the local population felt about the USA.