The intersection of Sanders and Yang supporters was highlighted last week when Sanders' former ad firm — Devine, Mulvey and Longabaugh — signed on with Yang's campaign. Mark Longabaugh, a partner at the company that produced Sanders’ famous “America” TV ad in 2016, told POLITICO that it chose Yang because “he’s offering the most progressive ideas.” The team had talks with at least one other presidential campaign about potentially working for it this cycle after splitting with Sanders earlier this year.

“He wants to transform the economy into an economy focused on people rather than corporate profits. That's the sort of progressive bedrock candidate that we're drawn to,” Longabaugh said. “Where a lot of candidates seem more negative and angry, I think Andrew comes to this displaying some optimism and a new way forward that could get this country to look to a new and better future.”

The Sanders-Yang overlap underscores another factor in the Democratic primary: While pundits frequently opine on “moderate” and “progressive” lanes, there's also an “anti-establishment” lane in which Yang, Sanders, Elizabeth Warren, Tulsi Gabbard, and Marianne Williamson are jockeying for support.

Just as Sanders is no longer the sole progressive in the race like he was in 2016, he isn’t the only anti-establishment contender anymore, either. Sanders seems to acknowledge as much.

Sen. Bernie Sanders is no longer the sole progressive in the race like he was in 2016, nor is he the only anti-establishment contender. | Scott Heins/Getty Images

“I like Andrew. Polling has shown my supporters support other candidates, polling has shown that other candidates' come over to us," he told POLITICO in an interview in Iowa on Friday. Sanders urged voters upset with the status quo to examine his decadeslong record of challenging the establishment: "These ideas that I am advocating now — I think in fairness, I’ve help transform politics in America — are not new ideas to me. I was out there fighting for Medicare for All 30 years ago.”

The contest for disaffected voters could be particularly fierce in New Hampshire, where independents can participate in the primaries. Exit polls showed Sanders won independents in his first presidential bid, and expectations for him in New Hampshire are high after he defeated Hillary Clinton there by 22 percentage points in 2016. Yang has also sensed an opportunity in New Hampshire, visiting it five times in the past three months and more than 20 times total.

“There is an intensity among the supporters of Andrew Yang that is very reminiscent of the Bernie supporters of 2016,” said Ray Buckley, chairman of the New Hampshire Democratic Party. “They’re very passionate about their candidate, and they are very active online, both on Twitter and Facebook, in expressing their strong support.”