[@ONL]

It could be argued too that the Japanese may see little value with allying with the Pacific States. Not only is the remnants of the US relatively weak, Japanese intelligence may suggest that any one of us may be a roadblock in the way to Pacific ambitions. It would  be more likely they seek an alliance with Mexico on the promise they get California back.

And Hawaii'd have enough Japanese migrant workers that holding the islands won't be an issue.