More to the point, assimilation doesn't mean turning Republican. Asians have proven this.
Do they really assimilate though? They mostly either live in Hawaii or concentrate together with others of their ethnic group in places like Hackensack or Edison in New Jersey or Buffalo Grove or Arlington Heights in Illinois. I suppose they're kind of everywhere in California, but even then, there are definitely areas of Asian concentration. I'm not sure I'd call that assimilation in the same way I wouldn't describe Italians as assimilated either, since 80% of them are still concentrated within 500 miles of NYC.