A senior adviser to Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE’s 2020 presidential campaign said Monday that the Vermont senator and progressive rival Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) aren’t necessarily competing for the same group of voters.

“Their bases really are not co-extensive. His base is much more diverse, much more working class,” Jeff Weaver, told Hill.TV during an interview on “Rising.”

“Her base is much more college educated and so they are not really at this point competing for the same pool of voters,” Weaver added, referring to Warren.

Weaver's comments come as polls show Warren rising and Sanders slipping.

Warren and Sanders are the 2020 race's two top progressive candidates and are seen as jockeying for support from the progressive base.

Warren has recently emerged as one of Biden’s most formidable rivals, with several recent nationwide polls showing the Massachusetts senator in second place to Biden, the front-runner.

Warren trailed Biden by just 1 percentage point, according to a poll released last week by Economist-YouGov Weekly tracking poll. The survey showed 21 percent of voters back Biden, while Warren is close behind at 20 percent.

A Monmouth poll also found Warren coming in second place to Biden in the Hawkeye State, with 19 percent support, compared to Sanders pulling 9 percent support among caucusgoers.

The Sanders campaign, meanwhile, has rejected the idea that its losing ground, claiming that the media is pushing a false narrative about the Vermont senator’s prospects.

Weaver echoed this sentiment, emphasizing that polls are still fluid.

“We’ve seen multiple frontrunners,” he told Hill.TV. “There’s a lot of fluidity and I think we’ll see that well into the fall.”

Warren and Sanders have largely avoided any direct attacks on one another. During the second round of Democratic debates in Detroit, the they both appeared on stage together and teamed up in defense of a number of progressive issues, including “Medicare for All.”

—Tess Bonn