What ever bitter feelings exist, many other Democrats say Sanders is key to rebuilding the party.

“If you are concerned with labels, you might bristle at the notion of a registered Independent jockeying for control over the direction of the Democratic Party – and there were certainly some in the party apparatus that expressed precisely this sentiment during the 2016 campaign cycle,” said Lynda Tran, a Democratic strategist.

“But if you’re focused on policy ideas over party labels you might welcome the inclusion of his voice, and frankly other voices too, at a time when the Democratic Party is under intense attack and working on the path forward.

“At the end of the day, Bernie Sanders may be a registered Independent, but he has always caucused with Democrats and there is no question he continues to enjoy strong support among many members of the Democratic Party,” Tran added.