What appears to have happened is that Sanders has become a stand-in for Warren among those Democrats who wanted the Massachusetts senator to run and are disappointed that she has declined. They have now transferred their support to the next-best candidate to represent their point of view, and that is Sanders.
One indication of that is in the PPP data from Iowa Democrats who describe themselves as “very liberal.” Among them, Clinton’s lead over Sanders is 55 percent to 29 percent — still a big lead at 26 points, but far less than Clinton’s 48-point lead among Democrats overall.
Yes, Clinton is far, far ahead. But in the big picture, the PPP results show that despite her lead, 38 percent of Democrats in the key early state of Iowa either do not want Clinton as their nominee or are not sure who they support. No, that’s not enough to win. But for her would-be opponents, it’s a start.