Elizabeth Warren is now the official front runner, per RCP. Their average of the polls now stands at Warren 26.6, Biden 26.4!
They use five credible polls to form the current average, and Warren has the edge in four of them. I personally expect Warren to pull quite a bit ahead, not so much because of Trump’s ongoing slander of Biden, but because of Bernie’s heart attack. I think we are going to see the Warren/Bernie wing consolidate behind Warren. We have seen little evidence of that so far, but I think it is inevitable. IBD shows that Bernie has dropped to 10%, which is the lowest he has been on any poll from a firm rated A- or better.
Kamala Harris is in fifth place behind Mayor Pete, and she’s also losing ground to Andrew Yang. (In fact, Yang beats her 8-to-4 in the latest Emerson poll, which is not used in the RCP average.)
Two of the five polls used in the average, Quinnipiac and IBD, are rated A- or better by the stats nerds at 538. Both of those polls show Warren in the lead. Both of those polls show that Buttigieg is in 4th, and that Yang has pulled into a tie for fifth with Harris.
I don’t think it would be as easy as Sanders supporters simply shifting over to Warren. Of course, I’m sure you don’t actually think it would be 100%, but earlier polling also showed a good deal of Sanders supporters would shift to Biden.
Much of Elizabeth Warren’s supporters are the old fashioned liberals that dominated the Democratic Party prior to Bill Clinton: middle class professionals, social activists and young people and public servants who live in the middle class suburbs. The obvious thing preventing Elizabeth Warren from dominating the Democratic primary is that the other major part of that coalition, blacks, still back Joe Biden over her by a wide margin.
(This is not to say an older style liberal can not win these days,
1.demographic shifts have made their supporters a much larger cohort
2.the issues of the day: income inequality and climate change favor those who want more government involvement in the economy.)
Much of Bernie Sanders’ support is more in line with those who support Joe Biden: older working class types (liberal working class types, more likely to be members of remaining private sector unions) who live in big cities and medium sized cities separate from the suburbs.
So, I think both Biden and Warren could each claim a fair share of Sanders’ support, if his support collapses.
Also, I would expect Andrew Yang to get at least 10% of Sanders’ supporters. I don’t think it’s difficult for a person to go from being a Bernie Bro to a member of the Yang Gang.