Barbara Lee supported Bernie Sanders' 2016 presidential bid, helping him score one of his most decisive victories that year when he dominated the New Hampshire primary. But as he wages another bid for the White House, Lee is looking at a different candidate.
Lacking the clear anti-establishment lane he had to himself in 2016, Sanders now must carve out a new one — and it's unclear exactly what that will look like.
"He has to be able to convince people that there's something distinctive about him," said veteran Democratic strategist Bob Shrum. "His speeches now, and what he says in the debates, are indistinguishable from what he said in 2016. In 2016, he was the new kid on the block, despite his age and he seemed fresh to a lot of people. Right now I think he's lost some of that sense of freshness."
Warren isn't the only Democrat on the rise who could potentially eat into Sanders' base. Voters making a generational choice have an alternative in a range of fresh Democratic faces who have only recently emerged on the national stage, including Mayor Pete Buttigieg of South Bend, Indiana , and California Sen. Kamala Harris .
And despite his talk of political revolution, Sanders risks being seen as part of the old guard, another politician in their late 70s like Joe Biden .
That's part of the reason John Jenkins, a 33-year-old public school teacher from Ames, Iowa, is considering other candidates.
"He's kind of a constant," said Jenkins, who supported Sanders in 2016 and recently attended one of his speeches.
His wife, Natalie Robinson, wore an "Our Revolution" t-shirt to come to see the senator — but she's also not sure if she'll support him this time around.
"They all agree on the issues," she noted, but "it's how they're going to make those issues better that matters."
Jenkins said he's considering Warren and Harris, whose "enthusiasm is very interesting to me."
And that, according to Charles Chamberlain, executive director of the progressive advocacy group Democracy for America, may be Sanders' biggest challenge — the fact that while some voters are interested in policy nuance, many are evaluating the candidates on personality.
"I don't think he should be changing his content," Chamberlain said. "What I do think would benefit him would be to think a little bit more about how to personalize his policy, so people can see he's not just an angry guy with a vision, he's also warm — like your grandpa."
Indeed, a number of the candidates have woven personal stories into their stump speeches and debate-stage performances in compelling ways. On the trail, Warren describes how the poverty she faced growing up informed her interest in banking reform. Harris made headlines — and won a bump in support — at last month's presidential debate after she attacked Biden in deeply personal terms over his opposition to busing .
For Alexis Falcone, a 27-year-old store manager from New Hampshire, the personal connection was what made her decide to shift her support from Sanders to Warren.
"I really feel like she's sincere and that she wants to help everybody," Falcone said.
Sanders' campaign has privately acknowledged they need to hold more intimate events and give him a chance to connect with voters personally, especially in early primary states like Iowa and New Hampshire, where retail politicking matters.
The senator took on a different format in Iowa last week, walking and greeting supporters in five parades; hosting a couple of ice cream socials and opening three new campaign offices across the state.
Still, he gave largely the same speech at an Ames office opening as he does at thousand-person rallies, railing against billionaires and corporate special interests while calling for his supporters to join his revolution. He left his own personal story out of it.
His campaign pushes back against any suggestion that he's losing support to other candidates. Jeff Weaver, a top Sanders adviser who served as his 2016 campaign manager, said he believed that while the field is more splintered this cycle, Sanders "has a strong base of active and motivated supporters and grassroots donors that are going to carry this campaign forward."
"Senator Sanders has always run in the same lane," Weaver said. "He has been working to uplift working people in every Zip code, and in marginalized communities. Regardless of what the race looks like, that will always be his lane. He's running to create a government and an economy that works for everyone, he was trying to do that in 2016, he's trying to do that today, he was trying to do that 20 years ago."
While other candidates may be competing for his voters, Sanders still saw strong enthusiasm during his recent Iowa trip, with overflow crowds at his Des Moines and Ames office openings and nearly 850 people at an Iowa City event that was planned to be much smaller.
After shaking his hand on the side of a Fourth of July parade in West Des Moines, Terri Steinmann, a 42-year-old real estate agent, said she was "verklempt" — a Yiddish word meaning "overcome with emotion." She says while she did think Sanders could move a bit more toward the center to appeal to moderate voters, she was still excited by his firebrand campaign, and still leaning toward supporting him in 2020.
"I kinda love him just the way he is," she said.
Jaffe reported from Des Moines, Iowa and Summers reported from Washington. Associated Press writer Hunter Woodall contributed from Peterborough, New Hampshire.