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Democrats may not be ready to feel the Bern a second time.

Some backers of Sen. Bernie Sanders (I-Vt.)'s 2016 presidential bid, including lawmakers as well as former staffers and advisers, spoke with The New York Times on Thursday and said they won't necessarily support him if he runs again in 2020. This includes Sanders' former press secretary, Symone Sanders, who said "there are a lot of good candidates this time" and that she'll "wait and see" who she backs.

Two other 2016 campaign staffers told the Times they'll be supporting Rep. Beto O'Rourke (D-Texas) if he runs; both helped organize his 2018 Texas Senate race. Additionally, a consulting firm led by three key Sanders 2016 aides also hopes to work for O'Rourke in 2020. A few devoted Sanders backers, though, did tell the Times they're ready to support him again in 2020.

But the Times spoke with plenty of others who were reluctant about Bernie 2020, including former Nevada state Assemblywoman Lucy Flores, who said it's "not a given" that she'll endorse him again. Rep. Raul Grijalva (D-Ariz.), the first congressman to endorse Sanders in 2016, said that "one has to wait and see who’s got the best chance mathematically."

A common concern among the Democrats the Times spoke to was Sanders' age; the Vermont senator would be 79 by the time he took office, which would make him the oldest president in U.S. history. Others noted that Sanders no longer sticks out among Democrats as much when many of his policy proposals, such as single-payer health care, have been adopted by other candidates, including O'Rourke and Sen. Elizabeth Warren (D-Mass.)

Progressive talk show host Bill Press, who thinks a Sen. Sherrod Brown (D-Ohio) 2020 bid could be the way to go, observed, "What I hear from a lot of friends is that a younger Bernie is what we need."