This Gallup poll from a few weeks ago almost slipped past without being noticed.

A couple days ago I showed how Dems that moved to the right have gotten massacred in the elections, while progressive candidates have survived the onslaught.
In that essay there was one study that stood out in my mind.

According to The Hill, "Clinton allies" are blaming Bernie Sanders for Hillary Clinton's poor performance in recent opinion polls. They complain that Sanders' continued attacks on Clinton and his failure "to begin bringing everyone together” hurts Hillary Clinton because it "... holds her back from controlling the narrative.” What I see are changes in the U.S.

Way back in January the Washington Post noticed that Hillary Clinton had difficulty getting the votes of anyone that didn't self-identify as a Democrat. Hillary had a -31 rating with Independents according to Quinnipiac polling.
The headline was "Independents like Hillary Clinton less than in 2008".

Clinton's numbers have gotten among Bernie Sanders supporters. 60% have an unfavorable view of her. https://t.co/qBPua9pS3a

I apologize ahead of time for the somewhat lightweight diary, but I decided to make it a diary rather than a comment b/c I want a larger number of people to see it and help me speculate on this question.