For Sanders, a key question is electability. Clinton is in a commanding position by any measure. Yet his supporters in New Hampshire say his local ties and longstanding practice of holding town hall meetings and people-to-people campaigning — a staple in the nation's first primary state — could serve him well.
"Toward the Vermont border it's like a love-fest for Bernie," said Jerry Curran, an Amherst, New Hampshire, Democratic activist who has been involved in the draft Warren effort. "He's not your milquetoast left-winger. He's kind of a badass left-winger."
"Hillary Clinton is a candidate, I am a candidate," Sanders said. "I suspect there will be other candidates. The people in this country will make their choice."
Whether Sanders can tap into the party's Warren wing and influence Clinton's policy agenda remains unclear. But he has been on the forefront of liberal causes as Clinton has seemed to be tacking to the left.
Clinton regularly refers to an economic stacked deck against American workers — rhetoric that offers comparisons to Warren's frequent description of the economic system being "rigged" against middle-class families.
Sanders' disdain for big money in politics is also shared by liberals. Clinton frequently tells voters that she would back a constitutional amendment to overturn the Supreme Court decision allowing super PACS to raise unlimited money. But Democratic super PACs are already lining up behind her.
"I'm not going to have a super PAC in this campaign," Sanders said. "I don't go to fundraisers where millionaires sit around the room and say here's a million, here's $5 million for your super PAC. That's not my life. That's not my world. And I think the American people are saying that is not what our politics should be about." He said the money he's raised so far has come from more than 100,000 individual donors, giving an average of $42 each.
Organizers of the pro-Warren effort say Clinton may still win over many of their supporters. Charles Chamberlain, executive director of Vermont-based Democracy for America, said Sanders would "fill the void" for some of the voters hoping for Warren to run. But not for all.