1) Roughly 1 in 3 Biden backers in the poll (32%) said they might vote for another candidate on Saturday. Just more than 1 in 10 Sanders supporters (12%) said the same. That's broadly consistent with what we've seen throughout this primary to date; Sanders has the most committed support, while Biden's has been among the least committed.
2) This poll was in the field from February 18 to February 21. On February 19, the top six Democrats appeared at a debate in Las Vegas. Because of that, the pollsters broke out interviews they conducted before the debate and those they conducted after it. In the pre-debate sample, Biden led Sanders by 10. In the post-debate sample, the two candidates were dead even. That suggests momentum was moving in Sanders' direction even before he won a surprisingly sweeping victory in the Nevada caucuses on Saturday.
3) Among voters with a clear candidate preference or those who had already voted, more than 7 in 10 (72%) Bernie-backers said they "strongly supported" him. Among those with preference for Biden that strong support was at 61%. Again, a clear passion/enthusiasm gap there.
4) Biden is still the first choice of black voters, but Sanders -- and billionaire businessman Tom Steyer -- are holding their own. Biden takes 35% among black voters to 20% for Sanders and 19% for Steyer. That's a stunning contrast to the 72 percentage-point margin that Sanders lost black voters to Hillary Clinton by in the 2016 South Carolina primary. For Biden to win, he badly needs to run up the score among black voters -- especially because he is losing whites to Sanders in this poll by 8 points. If Sanders and Steyer can combine to win 4 (or so) out of every 10 black votes in Saturday, Biden's path to victory get rockier.
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