That prediction is looking more precarious by the day (but hey, I do this for fun, while Nate Silver makes a living doing it, so cut me more slack than you cut him!). The first part is holding up--that non-whites won't back Sanders--but the second part--that liberal whites won't contradict non-whites--appears tenuous. Support among white Democrats in the latest Reuters/Ipsos five-day national tracking poll:
The same, among non-white Democrats:
The Clinton campaign's criticism of Bernie Sanders' implicit whiteness is drawn into sharper focus.
If having my powers of prognostication humbled is collateral damage in the process of the Coalition of the Fringes tearing itself apart, I'll suffer those slings every day!