No one is really sure why Latino and Asian Democrats tilted so heavily in favor of Clinton in the California primaries. One could suppose if the women leaned for Hillary and the men were evenly split it would create some of the gap, but that’s not enough. Policy wise, Obama and Hillary overlap heavily, but Obama tends to do better at pulling independants and moderates.
To correct the gross mis-statement Kev made, the Bush tax cuts that will be rolled back primarily only affect those making over $250k a year. I think most Americans have realized at this point that those tax cuts really only benefitted the uber-rich, while throwing a tiny bone to the middle class (And if you’re sub 100K a year, you’re middle class, and should vote Democrat if you’re voting with your pocketbook)