Sen. Bernie Sanders has spent more than a year running against what he calls a corrupt political system and thus far he’s refused to concede to presumed Democratic nominee Hillary Clinton, who Thursday won the endorsement of President Obama.
When Donald Trump gave his victory speech on Tuesday night he turned heads in the Democratic Party with one line in particular.
Audio for this piece will be posted.
"To all of you Bernie Sanders voters left out in the cold by a rigged system of superdelegates, we welcome you with open arms," Trump said to a cheering crowd.
That speech was read from a teleprompter, which shows Trump and his top advisers see an opening with Sanders' base.
Whether it's trade policy or shaking up business as usual in Washington, Trump thinks his platform resonates more with Sanders supporters than does Clinton’s resume as a Washington insider.
That’s partly why many Democrats are getting restless with Sanders and his refusal to step down and endorse Clinton. Florida Sen. Bill Nelson is one of them.
“I think he should stand down now, that’s my conclusion," Nelson says. "I believe that he is uniquely positioned to be able to be a unifier and that is so important when you consider that the November election is a study in contrast.”
Other Democrats, like Vermont Sen. Patrick Leahy, don’t want to pressure Sanders.
“I’ll let him speak to it," Leahy says.
Even Vice President Joe Biden this week cautioned members of his party who are pressuring Sanders to concede.
"It’s clear we know who the nominee is going to be but I think we should be a little graceful and give him the opportunity to decide on his own," Biden says.
But some Sanders supporters want to extract something tangible from the party before Sanders throws in the towel. Florida Democrat Rep. Alan Grayson is still backing Sanders in his long-shot bid. But he says the Democratic National Committee could win over Sanders and his supporters if they made some concessions now.
“Well, if you’re looking for a constructive suggestion," Grayson says, "I think if the platform committee were to accelerate its effort and demonstrate a real commitment to the Sanders progressive platform. I think that would move things along."
Grayson says calls for Sanders to drop out are premature.
"I play a lot of chess, you know, sometimes chess games end with a resignation, sometimes they end with a checkmate. If I’m playing against somebody and that player tells me it’s time for you to resign, I’ll say, ‘Look, let’s keep playing. Let’s see what happens.' I don’t think there’s anything wrong with that, that’s the way the game is played," says Grayson.
Other Sanders supporters now say Clinton’s nomination is inevitable and they’re ready to support her.
When asked what Sanders’ end game is and what he hopes to accomplish by sticking it out until the convention, Arizona Democrat Rep. Raul Grijalva says he's "not quite sure, honestly."
Grijalva is the co-chair of the Congressional Progressive Caucus and Sanders' first backer in Congress. He says the party may need to embrace Sanders before Sanders and his base can embrace the nominee.
“You know, we’re going to go to the convention and he’s going to have 45 percent of the pledged delegates," he says. "And the platform, I think, can be a very good unifying piece. So can some attention and validation of what Bernie did in terms of not just his delegates but himself.”
Neil Sroka, of the progressive group Democracy for America, says he’s not worried by Trump’s appeal to disaffected Sanders voters.
“It is insulting and absurd for anyone to suggest, including Donald Trump, that the millions of people who have rallied behind Bernie Sanders would in any way support his campaign for president," said Sroka.
But he still says the DNC needs to actively woo Sanders supporters by embracing parts of his message.
“I think there has to be a peace made for the populous progressive policies that Bernie Sanders has run on throughout this race," Sroka said.
Voters in Washington, D.C., will cast the final ballots of this primary season on Tuesday. After that, all eyes in the Democratic Party will be on Vermont’s junior senator, especially those of party leaders and the millions of voters who propelled him this far.
Matt Laslo is a reporter based in Washington, D.C. He has been covering Congress, the White House and the Supreme Court since 2006.