1- Most Japanese Americans live in overwhelmingly Democratic areas to begin with, and are not as culturally isolated as some political "islands" such as Native Americans in South Dakota or Orthodox Jews in Brooklyn.
2- Japanese Americans work disproportionately less in the industries Republicans fawn over (agriculture, mining, etc.) and disproportionately more in industries Democrats fawn over
3- Interestingly enough, the huge gap really started between 2004 and 2008, going from Kerry +4 to Obama +46. So perhaps there's some lingering mistrust following the Bush years.
4-
the racial dog-whistles of GOP leaders
