Sanders staying in the race is the best thing Biden could've asked for; he'd be close to double digits down if Warren got the bulk of his support
There's no evidence that she would. Biden is the top second choice of his supporters.
To be fair, FiveThirtyEight's new article shows that the evidence of who Sanders supporters' 2nd choice is is quite mixed. Morning Consult seems to be one of the few pollsters that Biden is in the lead among Sanders voters.
The best case for Warren if Sanders dropped out is it would be something of a wash, it's not like 90% of his support is going to magically transfer over to her.
Maybe if he endorsed her it would.
