Progressive commentator: Biggest mistake for Sanders, Warren would be to 'appeal to center'

Progressive commentator Sam Seder said Monday that progressive heavyweights Sens. Elizabeth WarrenElizabeth Ann WarrenSupport drops for Medicare for All but increases for public option Hillicon Valley: Warren takes on Facebook over political ads | Zuckerberg defends meetings with conservatives | Civil liberties groups sound alarm over online extremism bill Feehery: Trump may be down, but he's not out yet MORE (D-Mass.) and Bernie SandersBernie SandersSupport drops for Medicare for All but increases for public option Hillicon Valley: Warren takes on Facebook over political ads | Zuckerberg defends meetings with conservatives | Civil liberties groups sound alarm over online extremism bill On The Money: Trump touts China trade deal | Wall Street, Washington see signs for caution | Trump threatens sanctions on Turkey | Sanders proposes sharp hike to corporate taxes MORE (I-Vt.) shouldn't try to appeal to centrist Democrats. 

"I think just trying to appeal to the center," Seder, host of liberal talk radio program The Majority Report, told Hill.TV in response to a question over what would be the biggest mistake either candidate could make. 

“Both of them have a message to the extent that people perceive it as authentic,” he continued, adding their messages are “what’s going to bring out their voters.”

Seder also emphasized that there isn’t a clear sense of who the Democratic electorate is going to be, particularly in early state primaries.

“It’s sort of hard to know who is really going to show up in these early state primaries,” he said.

Both Warren and Sanders have emerged as top challengers to front-runner Joe BidenJoe BidenSupport drops for Medicare for All but increases for public option Bolton told ex-Trump aide to call White House lawyers about Ukraine pressure campaign: report Federal prosecutors in New York examining Giuliani business dealings with Ukraine: report MORE in recent months.

A new poll found Warren leading former the former vice president for the first time in Iowa. 

According to a Des Moines Register/CNN/Mediacom survey, 22 percent of likely Democratic caucusgoers in Iowa back Warren for president. Another 20 percent named Biden, the current front-runner, as their top choice.

—Tess Bonn