Howard Dean: Sanders could cost Dems the White House
© Getty Images
"This is a critical juncture, which I'm not sure he has yet understood. How he leaves this race and what he does afterward matters a lot," Dean, the former presidential candidate and Hillary Clinton supporter, said on "Special Relationship," a joint podcast with Mic and The Economist. 
"He could end up being the next Ralph Nader, who deprives the Democrats of the Congress and ends up electing, well I don't know what to call Donald TrumpDonald TrumpThe Hill's Morning Report - Presented by Facebook - White House, Dems play blame game over evictions The Memo: Left pins hopes on Nina Turner in Ohio after recent defeats Biden administration to keep Trump-era rule of turning away migrants during pandemic MORE but certainly nothing flattering. If he sustains his movement, as we did in our campaign, he could be very successful in changing the course of American politics."
Dean, a Vermont politician with his own populist streak, ultimately lost his presidential primary bid in 2004 and said that Sanders needs to realize what he realized — that the race isn't personal, but instead about what's best for the country. 
"I think he's struggling ... the race is over, he hasn't acted like it," said Dean, who became Democratic National Committee chairman after his failed run.
"The sooner he comes to grips on what he's going to do between now and November, we'll find out what his legacy will be."
He added that he believes about 80 percent of Sanders's supporters will ultimately come in line with the Democratic Party and vote for Clinton, but 15 percent will break for Trump because Sanders has a "tremendous attraction to working class people who tend to vote more conservatively." 
The idea of party unity is the biggest topic of conversation in Democratic circles right now. Sanders has shown no signs that he'd drop out and endorse Clinton, but he's meeting with President Obama and Senate Democrats Thursday before a rally in Washington in what many believe will be the first steps toward reconciliation.