Sen. Bernie Sanders' (I-Vt.) 2016 flame might be fizzling out.

Just like nearly every other 2020 poll out so far, Sanders finds himself in second place in a Monmouth University poll released Monday. The biggest portion of Democrats, 28 percent, say they'd support Vice President Joe Biden for the 2020 nomination should he decide to run. As usual, Sanders comes in second with 25 percent, and his retreating 2016 base could explain why.

Sanders, who came close to clinching the Democratic nomination in 2016, could top the polls if all his past supporters returned. But in the Monmouth poll, only 46 percent of Sanders' 2016 backers said they planned to vote for him this time around. Biden gets 15 percent of Sanders' old squad, with Sen. Kamala Harris (D-Calif.) and Sen. Elizabeth Warren (D-Mass.) next in line.

Still, some Monmouth findings are looking up for Sanders. He attracted 14 percent of past Hillary Clinton voters, the poll found. He's also the second most favorable and second most recognizable candidate in the pool, coming in just behind Biden on both counts. And if the ex-vice president declines to run, a quarter of Biden backers said they'll switch to Sanders.

Monmouth surveyed 310 registered and leaning Democratic voters via telephone from March 1 to 4, with a margin of error of 5.6 percent. Find the whole poll here. Kathryn Krawczyk